Is there still a place for prolonged bladder distension? Over a 2-year period, 31 patients underwent prolonged hydrostatic bladder distension for benign and malignant bladder disease in this unit. Of these, 29 patients had benign functional disorders or bladder contracture, and in 2 patients hydrodistension was performed for complications of treatment for bladder neoplasia. Of the 29 patients with benign disease, 6 observed marked improvement and 8 some improvement in their symptoms, and 12 received no benefit. Patients with detrusor hypersensitivity fared better than those with detrusor instability or interstitial cystitis. A patient with malignant bladder disease died soon after the procedure as a result of a myocardial infarction. Problems attributed to the hydrostatic balloon catheter were responsible for 2 failures. The regional anaesthetic technique failed to provide adequate anaesthesia for hydrodistension in 9 procedures and limited the duration to 2 h in 13 others. Following recall of the perished balloon catheters by the manufacturer, and the introduction of continuous spinal anaesthesia, the number of technical failures has been reduced. This technique still has an important role to play in the relief of severe symptoms unresponsive to medical treatment, but it is important that ideal conditions are provided for hydrodistension in order to ensure maximum success, particularly when the alternative is major surgery.


Botulinum toxin in the treatment of chronic urinary retention in women. Six women were identified as having difficulty in voiding or complete urinary retention due to abnormal myotonic-like electromyographic (EMG) activity in the striated muscle of the urethral sphincter. An attempt was made to improve voiding by injection of botulinum toxin into the striated sphincter muscle. Although 3 patients then developed transient stress incontinence, demonstrating that sufficient botulinum toxin had been given to cause sphincter weakness, no patient had significant symptomatic benefit.


The open access Continence Resource Centre for Greater Glasgow Health Board. The development of an open access Continence Resource Centre is described. The role of the Centre in helping the sufferers and carers is highlighted. The educational role exceeded expectations. The benefits of the centre in education, research and potential cost saving are discussed. The aims and achievements are in accord with the Department of Health document "An Agenda for Action on Continence". From its opening in August 1989 to the end of February 1992 the centre has served 8070 incontinent individuals and 4736 carers. At a cost of 44,000 pounds per annum this represents good value for money.


Preliminary results of concurrent cisplatin and radiation therapy in locally advanced bladder cancer. Between March 1981 and March 1990, 15 patients with locally advanced transitional cell carcinoma of the bladder were treated concurrently with cisplatin and radiotherapy. Treatment comprised a radiation dose of 40-50 Gy in 20-25 fractions over 4-5 weeks and intravenous infusion of cisplatin with hydration during days 1-5 and 22-26. The total scheduled dose of cisplatin was 200 mg. A complete response (CR) was seen in 3 patients (2 T2 tumours and 1 T3) and the other 12 were regarded as partial responders. Two of the 12 partial responders (1 T2 tumour and 1 T4) underwent cystectomy after treatment, but 9 patients (2 T2, 6 T3 and 1 T4) underwent only transurethral resection. The remaining patient (with a T4 tumour) died from systemic disease, further treatment not being possible because of unrelated heart failure. In 3 CR patients and 9 with a partial response (PR), bladder function was preserved and they have survived for a mean of 18.3 months (range 5-47) after therapy. Although 4 patients in this group had recurrent bladder tumours and 1 died from cancer in another part of the body, 7 have survived with normal bladder function and no recurrence. It is concluded that concurrent cisplatin and radiation therapy is a safe and viable regimen and may be considered as a means of preserving the bladder in patients with locally advanced transitional cell carcinoma.


Cold sensation and bladder instability in patients with outflow obstruction due to benign prostatic hyperplasia. A series of 73 patients with bladder outflow obstruction caused by benign prostatic hyperplasia underwent urodynamic investigation, including the cold water test. The presence of detrusor instability was associated with a higher urethral opening pressure, maximum detrusor pressure and detrusor pressure at maximum flow. Instability was more common and more pronounced in patients with a lack of cold sensation, but there were some patients who, whilst lacking cold sensation, still possessed the cold reflex. This suggests partial denervation of the bladder or some form of altered modulation of sensory activity within the spinal cord or central nervous system. On the other hand, some of the patients lacked cold sensation but showed a stable detrusor and a high maximum cystometric capacity. This leads to the conclusion that there are different mechanisms by which the bladder reacts to outflow obstruction.


Is indoramin an effective alternative to prostatectomy? Alpha-1-adrenergic antagonists are recommended for symptomatic treatment of patients awaiting prostatic surgery. Their efficacy has been confirmed in placebo controlled clinical trials, but to date no comparison of their effects with the results of subsequent prostatectomy has been made. Fifty-five patients awaiting prostatectomy were assessed (by symptom scores and peak urinary flow rates) prior to treatment, on indoramin 20 mg bd, and 2 months following prostatectomy. Side effects while taking indoramin were experienced by 36% of patients. Despite an overall improvement in mean symptom scores, 26% of patients with obstructive and 30% of those with irritative symptoms who were assessed while taking indoramin failed to experience any improvement. Of the 31 patients assessed while on indoramin and again following surgery, prostatectomy produced a greater symptomatic relief than indoramin. The increase in peak flow rate following prostatectomy was 11.7 ml/s compared with 3.2 ml/s on indoramin. However, 5 patients preferred to continue taking indoramin rather than proceeding to surgery. Indoramin is no substitute for prostatectomy. Although some patients might benefit from treatment while awaiting surgery, significant side effects may severely restrict its use for this purpose. The response to indoramin cannot be used as an accurate predictor of response to prostatectomy.


Outcome and prognostic factors in patients with advanced prostate cancer and obstructive uropathy. In a series of 51 patients with prostate cancer and obstructive uropathy, unilateral or bilateral obstruction was identified in 22 (43%) and 29 (57%) respectively. This included a non-functioning kidney in 12 patients. In 86% of patients the T category was advanced. Bone metastases were present in 36 cases (71%); 19 patients (37%) had chronic retention. All patients with metastatic disease underwent hormonal manipulation and 43 underwent transurethral resection of the prostate. External beam radiotherapy, percutaneous nephrostomy and ureteric reimplantation were performed in 4, 5 and 1 patient respectively. Actuarial survival of all 51 patients was 57 and 25% at 2 and 5 years. Presentation with bilateral or non-function did not predict a worse prognosis in comparison with patients with unilateral hydroureteronephrosis. Raised alkaline phosphatase and prostatic acid phosphatase were of no prognostic value, while creatinine reached marginal significance. A positive bone scan and raised urea were strongly predictive of a poor outlook. It was concluded that prostate cancer and obstructive uropathy should not uniformly imply a terminal event, and interventional therapy is justified with a 25% 5-year survival rate.


Testicular denervation. A new surgical procedure for intractable testicular pain. Chronic testicular pain has many different aetiologies. Identification and treatment of an underlying problem resolve the issue in most cases. However, a proportion of patients with chronic testicular pain have no demonstrable aetiological factor and pose a difficult treatment problem. All of these patients are initially treated by non-surgical measures. Various operations advocated in the literature for non-responders include epididymectomy, scrotal orchiectomy and inguinal orchiectomy, all of which have a significant failure rate. We describe a hitherto unreported operative procedure in a series of 4 patients, with immediate and lasting relief of their pain.


Testicular prostheses: the patient's perception. There is a paucity of data to determine if the insertion of a testicular prosthesis is effective in overcoming the psychological effects of an absent testis. A review of 25 patients who had had testicular prostheses showed a high overall level of satisfaction in the 19 patients who were traced. This satisfaction was subject to some qualification.


In vitro investigations into the formation and dissolution of infection-induced catheter encrustations. Encrustations are the most frequent complications occurring with indwelling catheters and urine drainage systems. The conditions for bacterial infections, using synthetic urine and controlled contamination by Proteus vulgaris, were standardised by using an in vitro model. Crystal deposits on catheters were analysed by infra-red spectroscopy and scanning electron microscopy. The main components of deposits in all investigations were struvite (MgNH4PO4.6H2O) 60-70% and carbonate apatite (Ca10(PO4,CO3)6 (OH,CO3)2) 30-40%. Investigations as to the quality and quantity of encrustations confirmed the analysis. Irrigation treatment was carried out with physiological saline solution and citric acid solution (Suby G) to study and quantify the dissolution of crystal deposits. Regular irrigation with citric solution resulted in a 70% dissolution of encrustations and ensured free flow as ascertained by measuring flow rates.


Familial hollow visceral myopathy with varying urological manifestations. A family with hereditary hollow visceral myopathy is described, with characteristic variation in expression between affected members. Very severe and widespread involvement of the gastrointestinal and urinary tracts in 1 patient contrasted with isolated urinary tract involvement in 2 others, and it is suggested that hollow visceral myopathy should be considered in the differential diagnosis of primary detrusor failure. The management of urinary tract involvement is discussed and a conservative approach is recommended.


Endoscopic reappraisal of the morphology of congenital obstruction of the posterior urethra. Congenital obstruction of the posterior urethra was first systematically classified by Young in 1919. Since then, no-one has seriously challenged the presence of both Type I and Type III "valves", although the presence of Type II lesions has often been disputed. A review of Young's papers and more recent anatomical studies, together with endoscopic findings in our own patients, indicates that most congenital posterior urethral obstructions are anatomically similar. Consequently, Young's classification now seems redundant.


Epidemiology of the menopause.

Epidemiology of the menopause. Profound changes in birth and mortality rates in this century are resulting in the ageing of the population of Britain and other developed countries. The enormous decline in maternal mortality, in particular, has meant that increasing proportions of women are surviving to the menopause and years of active life beyond it. Women aged 55 years and over now comprise 15% of the population of Britain. The average life expectancy for women in developed countries is around 75 years; approximately 90% of women reach the age of 65 years, and 30% reach 80 years. If the average age of menopause is 50 years, most women will spend approximately one third of their lifetime in postmenopausal life; one in every two women will experience about 30 years of postmenopausal life.


Endocrinological aspects of the menopause. On average women live for about 30 years after the menopause. About 60-70% of consultations at the general practitioner and hospital specialist levels are for people over the age of 60, the majority of who are females. Therefore it is crucial to examine the effect of oestrogen prior to the menopause and how it interacts with other systems at cellular level. It is also important to examine why cells multiply and differentiate more efficiently in an oestrogenic milieu. This will give a better understanding of the degenerative processes of the menopause and will have profound implications on the design of effective hormone replacement therapy protocols.


Hormone replacement therapy and cardiovascular disease. Oestrogen alone probably confers a degree of protection against ischaemic heart disease and stroke and is appropriate for women requiring hormone replacement therapy (HRT) who have undergone hysterectomy. However, the cardiovascular effects of the progestogens used with oestrogen in the much larger number of women who have not undergone hysterectomy are unknown. Some widely used progestogens have adverse effects on lipoprotein levels and may raise blood pressure. The antithrombin III level may be involved in determining the response to oestrogen in different settings. The indications for HRT and the effects of different formulations on cardiovascular disease constitute one of the most pressing but complex issues in present-day medical practice. These questions can only be satisfactorily answered by the randomised controlled trials that should have been initiated several years ago and the feasibility of which is only now being investigated.


HRT and osteoporosis.

HRT and osteoporosis. Osteoporosis is characterised by low bone mass, leading to an increased risk of fragility fracture, particularly in the femoral neck, vertebrae and radius. These fractures constitute a major public health problem in the Western world; the estimated annual cost to the health services of hip fracture alone is over 500 million pounds in the United Kingdom. Using population-based data from the USA, Cummings et al. have estimated that the lifetime risks of hip, vertebral and Colles' fractures in a 50 year old, white, postmenopausal woman are 16%, 32% and 15% respectively. Of these, vertebral fractures probably cause the most significant morbidity, since they occur at a younger age than hip fractures and may result in pain, deformity and disability for many years until death intervenes from other causes. Hip fractures occur most commonly in the eight and ninth decades of life and have a mortality at six months of around 15%, increased dependency occurring in the majority of survivors. Colles' fractures, although not usually associated with long-term morbidity, nevertheless cause considerable inconvenience and require hospital treatment.


Hormone replacement and cancer.

Hormone replacement and cancer. The increasing extended use of noncontraceptive oestrogen by postmenopausal women, intended to prevent other conditions, may at the same time increase their risk of reproductive cancer. The risk of endometrial cancer triples after only a few years of unopposed oestrogen, persists for many years after oestrogen has been discontinued, and appears to be preventable by the addition of a progestin. The effect of replacement hormones on the risk of breast or ovarian cancer is unknown. Most studies suggest a small but significant increased risk of breast cancer after long-term use. Awareness of the known and uncertain cancer risks should be included in decisions to use replacement hormones.


Hormone replacement therapy and other menopause associated conditions. In Britain a large majority of the women who use Hormone Replacement Therapy (HRT) use it in order to alleviate symptoms thought to relate to the menopause. These include vasomotor instability, 'minor' psychological disturbance and sexual difficulties. Other HRT effects gained by the women include effects on maintenance of collagen, as in the skin, and on oestrogen sensitive tissues related to the lower urinary tract.


HRT: an analysis of benefits, risks and costs. A cost-effectiveness analysis of hormone replacement therapy (HRT) was undertaken to assess the relative benefits of different treatment strategies, and to identify which factors most influence cost-effectiveness. The current lack of conclusive evidence on the effects of HRT, especially in relation to combined therapy and cardiovascular disease, necessitated the use of a large number of assumptions in our model. In terms of net health benefits, the potential reduction in cardiovascular disease would have greatest impact, and would overshadow any small increase in breast cancer risk possibly associated with long-term use. Net expenditure by the NHS will depend critically on the direct costs of treatment, rather than on any indirect costs incurred or averted as a result of side-effects. In terms of cost-effectiveness, long-term prophylactic treatment of hysterectomised women and treatment of symptomatic women with a uterus compare favourably with other accepted health care interventions.


HRT: developments in therapy.

HRT: developments in therapy. Various forms of oestrogen have been available for use as Hormone Replacement Therapy (HRT) for approximately 50 years. However, there has been little change in the mode of administration until the last 10-15 years. Although the oral route has remained the mainstay of therapy, non-oral routes of administration have been developed. During the 1970s it became clear that use of unopposed oestrogens in women with an intact uterus resulted in an increase in risk of endometrial carcinoma and thus the current practice of adding a sequential progestogen each month, to prevent endometrial hyperplasia, was introduced. However, certain progestogens can cause side-effects and some of the metabolic changes which they induce are potentially undesirable. Thus the search continues for new oral progestogens which are more 'metabolically friendly' than those in current use. Additionally, non-oral delivery systems for progestogens have been studied, such as the transdermal route (patches) and local administration within the uterine cavity (progestogen-containing intra-uterine devices). Both these strategies may minimise their symptomatic, psychological and metabolic effects. Continuous (every day) administration of progestogens in combination with the oestrogen, or the use of new compounds (e.g. tibolone) may overcome the problem of regular withdrawal bleeding which some women find unacceptable. However, it remains to be determined whether such therapies are as efficacious as conventional oestrogen/sequential progesterone regimens.


Management of the menopause.

Management of the menopause. The management of the peri- or postmenopausal patient, whether symptomatic or asymptomatic, involves a careful assessment of the problems and expectations of each patient and the matching of appropriate treatment to their needs. The effects of the menopause and its treatment on the patient's immediate and long-term health must be taken into account. This may involve consideration of aspects of medical topics as diverse as gynaecological endocrinology, bone metabolism, oncology and cardiology. Although the benefits of oestrogen therapy are well established the response to therapy must be carefully monitored. Vigilance in the monitoring and seeking out of adverse effects both in individuals and populations must continue to ensure that any problems with this form of therapy are detected at the earliest possible stage.


Future prospects for hormone replacement therapy. To avoid the complication of osteoporosis, hormone replacement therapy (HRT) is now standard therapy in women with premature ovarian failure. The indications for HRT after the age of 50 are more controversial. There are strong indications from case-control studies that in N. America and Europe HRT protects against osteoporotic fracture, myocardial infarction and stroke; yet the evidence from case control studies is insufficiently precise to quantitate accurately the potential benefits that would accrue from its more widespread use. Clear guidelines also need to be established on the potential usefulness of selective prescribing of HRT using one or more screening procedures. The only effective way of achieving this and of quantitating the potential benefits of HRT with sufficient accuracy is by means of one or more randomized controlled trials. Future research will also address concerns such as the possible increase in the risk of breast cancer after 10 or more years of therapy. Critical to the more widespread acceptance of HRT may be the development of safe regimes which do not promote uterine bleeding as well as minimizing other unwanted side-effects.


Sport and the overtraining syndrome: immunological aspects. Acute exercise of varying severity and corresponding levels of long term competition and training have been found to affect various components of the immune system including lymphocyte subsets, immunoglobulin levels, the mononuclear phagocytic system, polymorphonuclear leukocytes and cytokines, especially IL-1, IL-2, IL-6 and TNF. A tentative trend may be discerned whereby light to moderate exercise may increase immune responsiveness but high-level competition sport, especially if it involves extensive endurance training, may lead to a degree of immunosuppression. Such immune malfunction may be a component of the overtraining syndrome, in which recurrent infections during periods of maximum training or competition stress may form part of the syndrome. Evidence is presented that such overworked muscle may fail to supply adequate glutamine for normal lymphocyte function. Principles of an overtraining treatment strategy are suggested.


Sudden cardiac death in athletes.

Sudden cardiac death in athletes. Sudden death in athletes is a rare but tragic occurrence. Congenital cardiovascular abnormalities, usually asymptomatic and often undiagnosed during life, are the main causes in young athletes. Hypertrophic cardiomyopathy and congenital coronary anomalies are the most commonly occurring disorders. Idiopathic concentric left ventricular hypertrophy (non-physiological), arrhythmogenic right ventricular dysplasia and Marfan's syndrome with aortic rupture have also been implicated. Rarer causes include mitral valve prolapse and myocarditis. Coronary atherosclerosis is the major cause in older, and occasionally in younger athletes. Those involved in the medical care of athletes should be aware of the potential causes of sudden death in these groups. Symptomatic athletes should be fully investigated. Screening programmes are probably not justified on a cost effective basis.


Exercise, amenorrhoea and the skeleton.

Exercise, amenorrhoea and the skeleton. One of the accepted benefits of regular exercise is the development of increased bone mineral density (BMD) and hence a skeleton more capable of withstanding the rigours of physical activity throughout life. However an apparent paradox is seen in the observed decrease in lumbar BMD in female athletes who experience menstrual disturbance and athletic amenorrhoea (AA). Despite high levels of activity these athletes suffer the consequences of hormonal deficiency and are at risk of not achieving peak BMD and experiencing further bone loss. It is increasingly evident however that exercise itself continues to exert a protective effect of maintaining BMD at skeletal sites under physical stress. The observed increase then of stress fractures at these sites in amenorrhoeic athletes remains unexplained.


The growing child in sport.

The growing child in sport. An increasing number of children undergo intensive training routines and high level competition from an early age. Although physical training may foster health benefits, many are injured as a result of it. Carefully controlled studies on the effects of training routines from childhood are however lacking. This paper reviews some of the effects of training in young athletes, focusing on physical, cardiovascular and muscular effects, and sports injuries. Psychological effects of intensive sports participation are briefly considered. Measures should be taken to modify the present structure of competitive sport to avoid the possible deleterious effects of intensive physical activity on children.


Aerobic exercise, anaerobic exercise and the lactate threshold. All exercise draws first on intramuscular stores of ATP and creatine phosphate; initially these are replenished by anaerobic glycolysis. The lactic acid produced contributes to the rapid development of fatigue in high intensity exercise. Aerobic metabolism (at first mainly of glycogen, later increasingly of fat) is the principal route of ATP resynthesis in activities lasting longer than 2 min, but can only maintain work-rates about 1/4 of those possible in very brief bursts. Blood lactate rises at the higher aerobic work rates. 'Lactate threshold' (LT: approximately 2 mmol/l) is almost exactly the speed at which endurance races are won, and close to those apparently providing optimal aerobic training. This training, predominantly of muscle aerobic capacity, elevates LT more than maximum oxygen consumption. LT is not now thought to indicate oxygen-deprivation, but intracellular adjustments driving oxidative phosphorylation faster. Ventilatory breakpoints, formerly considered to indicate LT, correlate more closely with the accumulation of potassium than lactate.


Strength of skeletal muscle and the effects of training. The performance of any sporting activity involves a combination of skill and strength and it is very difficult to disentangle their separate contributions. The strength of an individual muscle depends on a number of factors. The major factor is the cross-sectional area of the muscle but others include the extent to which the muscle can be activated by voluntary effort, the overall length of the muscle and the position in which it is used, the fibre type composition and the velocity at which the movement takes place. Over a period of 2 to 3 months the major benefit of training is to improve the skill with which the training exercise is carried out. The effect is very specific so that there is considerable doubt as to whether weight training does anything other than train the athlete to lift weights. Increases in muscle size and strength in a healthy athlete occur relatively slowly and apart from the fact that high forces are required, little is known about the factors which stimulate growth. Accumulation of metabolites and damage to the muscle fibres are possible stimuli for growth but the prescription of optimal training regimes remains a matter of personal choice between the athlete and trainer rather than athlete and physiologist.


Food and drink in sport.

Food and drink in sport. The nutrition and fluid requirements of a sportsperson should be tailored not only to the sport, with endurance being the most important variable, but also to the individual competitor and the physical environment at the time of the event. This applies especially to fluid intake. There is agreement that the proportion of carbohydrate in the diet should be high and that of fat low. The evidence for increased metabolic demands for vitamins and minerals (except possibly calcium and iron) in exercise is equivocal. Fluid is still the priority constituent that needs monitoring.


Psychological stress, performance, and injury in sport. This paper reviews the empirical literature on psychological stress in sport, and the effects that such stress may have upon performance, vulnerability to injury, and rehabilitation from injury. It also examines the strategies that sports performers could use to overcome these effects. The major sources of stress that have been reported by sports performers include fear of failure, concerns about social evaluation by others (particularly the coach), lack of readiness to perform, and loss of internal control over one's environment. Various models and theories of the effects of such stress upon performance and vulnerability to injury are reviewed, including multidimensional anxiety theory and a catastrophe model of anxiety and performance. The cognitive and physiological processes which are thought to underly these effects are also reviewed, together with the intervention strategies that are implied by these processes. Research on the psychological stress that appears to be experienced by performers when they are injured is very limited. However, that which is available suggests that many of the same psychological skills that are thought to enhance performance can also be used to reduce the risk of injury, and promote a speedy recovery from injury. These include goal-setting, imagery, self-talk, and relaxation skills.


Exercise in prevention of disease.

Exercise in prevention of disease. Measures to increase individual participation in adequate amounts of physical exercise have a key place among the strategies to improve health and prevent disease. The scientific justification is based on a variety of evidence drawn from numerous epidemiological, clinical and physiological studies and is accepted as sound. The prevalence of physical disability is high. Disability attributable to age or chronic disease is helped by exercise. Inactivity compounds the effects of disability--an effect which deserves recognition because it is reversible and not inevitable. The association between a high level of habitual physical activity and a reduction in the individual risk for coronary vessel disease (CVD) is real and appears to be causal. Regular vigorous aerobic exercise is certainly effective in maintenance of health. Weight-bearing exercise has been shown to prevent osteoporosis at any age. The links between many of the functional adaptations which occur with exercise and improvements in health have been demonstrated. The exercise programmes which are effective have been defined.


Focal points in orthopaedics.

Focal points in orthopaedics. Orthopaedic surgeons have long had an association with sport, although it is arguable whether Galen who was the first sports medicine doctor, appointed to the Pergamum Gladiators in 157 AD was a surgeon by todays definition. This surgical role is now out of proportion to the more global aspects of sports medicine as reflected in the rest of this publication, but accurately related to the consequences of injury to the elite performer, where a minor injury may have a major consequence. As the title makes clear this chapter is a series of cameos some describing aspects of the management of common injuries and others indicating new developments.


Exercise, injury and chronic inflammatory lesions. The increasing frequency of injury over the last two decades reflects the activities of a more exercise conscious public. However, all too often injury may be due to ill-advised or inappropriate exercise and can be prevented by relatively simple modification of technique, equipment or gait abnormalities. Nevertheless, many injuries may simply reflect overtraining and the effects of repetitive strain on soft tissue and bony structures. This has led to an urgent need to understand better the mechanisms of injury, the importance of chronic inflammation and the factors involved in recovery of soft tissue strength. In the case of injuries to tendons or ligaments it is often difficult to define the contribution to symptomatology of collagen breakdown or chronic inflammation as a response to this. Furthermore, radiological changes at tendon and ligament attachments (entheses) through overuse can be indistinguishable from chronic inflammatory conditions such as spondarthritis, adding weight to the view that the body has a limited number of ways in which it can react to a variety of chronic stimuli. Marathon runners or footballers, for example, may develop symphysitis through chronic loading and radiologically there may be apparent erosive changes. Rheumatologists, dealing primarily with the chronic inflammatory arthritides, are beginning to understand better the factors involved in chronic inflammation and the effects of exercise. The Sports Physician must equally be aware of some of the pitfalls of misdiagnosis because of the masquerading of some primary inflammatory conditions as soft tissue injury or 'traumatic' joint effusion. This article will therefore review advances in current understanding of the influence of exercise on chronic inflammation and on recovery of tissue strength in sporting injuries. Improving understanding should lead to more defined rehabilitation programmes and a reduction in the all too common reinjury cycle.


Gender verification testing in sport.

Gender verification testing in sport. Gender verification testing in sport, first introduced in 1966 by the International Amateur Athletic Federation (IAAF) in response to fears that males with a physical advantage in terms of muscle mass and strength were cheating by masquerading as females in women's competition, has led to unfair disqualifications of women athletes and untold psychological harm. The discredited sex chromatin test, which identifies only the sex chromosome component of gender and is therefore misleading, was abandoned in 1991 by the IAAF in favour of medical checks for all athletes, women and men, which preclude the need for gender testing. But, women athletes will still be tested at the Olympic Games at Albertville and Barcelona using polymerase chain reaction (PCR) to amplify DNA sequences on the Y chromosome which identifies genetic sex only. Gender verification testing may in time be abolished when the sporting community are fully cognizant of its scientific and ethical implications.


Pathophysiology of soft tissue repair.

Pathophysiology of soft tissue repair. Inflammation with subsequent migration of leucocytes and connective tissue cells to the site of damage, together with the release of cytokines by these cells are essential for healing in common sports injuries. Injury to the musculotendinous unit resulting from either blunt trauma, tears or laceration, heal primarily by formation of granulation tissue and scarring. Early diagnosis with appropriate therapy may minimize any potential loss of function. Ligament repair also follows a classical healing response, although the quality of healing is site dependent and may be related to exposure to synovial fluid. In contrast, cartilage, which is avascular, lacks the inflammatory response seen in other connective tissues and this frequently results in poor tissue repair with subsequent degeneration of the injured cartilage. Mechanisms of repair in these tissues are described.


Morphology, behavior, and evolution: comparative kinematics of aquatic feeding in salamanders. The kinematics of aquatic prey capture were studied in species representing six salamander families (Ambystomatidae, Amphiumidae, Cryptobranchidae, Dicamptodontidae, Proteidae, and Sirenidae) to test the hypothesis that the process of aquatic prey capture is similar in these families. Seven variables were digitized from high-speed video records of prey capture, and a nested analysis of variance was performed to test for both significant individual within taxon and among taxa effects. The time-to-peak head angle and gape variables showed no taxon effect, while the other five variables exhibited highly significant differences among taxa. Cryptobranchus and Siren showed the most divergent kinematic pattern from the other taxa in a multivariate analysis of all variables, while Ambystoma, Dicamptodon, and Amphiuma tended to have similar overall patterns of head movement. These results show that kinematic patterns during aquatic feeding are not conserved across salamander taxa, and that phylogenetic differentiation in head morphology has been accompanied by novelties in feeding function. The feeding mechanisms of Cryptobranchus and Amphiuma have a bidirectional hydrodynamic design with kinematic correlates that are similar to kinematic characteristics of aquatic feeding in turtles and transformed ambystomatid salamanders. A general framework is presented as an aid to understanding the interrelationships among muscle activity patterns, morphology, and behavior (kinematic patterns). By considering the distribution of taxa in three multivariate spaces, corresponding to three of the levels at which one might analyze a behavior (kinematics, morphology, and motor pattern), it is possible to identify patterns of correspondence among the levels, which aid in understanding the evolution of behavior.


Changes in retinal projections and ganglion cell morphology after unilateral enucleation in the common carp. Changes in retinal projections and ganglion cell morphology were studied in one-eyed individuals of the common carp, Cyprinus carpio, which were enucleated at a juvenile stage (within 6 months after hatching) and kept for 18 months after the operation. Gross examination of the brains showed a marked atrophy of the contralateral optic tectum and a fine attenuated optic tract ipsilateral to the remaining eye. All retinal recipient areas were bilateral, but numerous projections were heavier contralaterally. Terminal branches in the recipient areas showed more complex patterns with tortuous courses and larger numbers of terminal swellings than in normal animals. Total numbers and distribution patterns of ganglion cells in Nissl-stained retinal whole mounts of one-eyed carp were compared with those in normal carp. The total number of ganglion cells was estimated to be 14 x 10(4)-18 x 10(4) in both one-eyed and normal carp. No difference was observed in isodensity maps and soma area histograms between one-eyed and normal carp. Following injections of horseradish peroxidase and nuclear yellow into the optic tectum of each side, three different types of tectal projecting ganglion cells were observed in the remaining retina: contralaterally projecting (CP) cells, ipsilaterally projecting (IP) cells, and bilaterally projecting (BP) cells. The distribution pattern of CP and BP cells in the retina suggested normal retinotopy. However, BP cells were found in a more restricted zone within the CP cell distribution area. The IP cells had a tendency to be scattered sparsely in a wide central area and a dorsal quadrant of the retina. No IP or BP cells were found in the peripheral retina. The time course and morphological changes in axons of these cells are discussed.


Physiological characterization of lateral line function in the Antarctic fish Trematomus bernacchii. The Antarctic notothenioids are a monophyletic radiation of fishes that have evolved under conditions of low light and cold, where non-visual sensory systems, such as the mechanosensory lateral line system, would be of importance. As part of a study of the structure and function of the mechanosensory lateral line system in these fishes we systematically characterized the function of the anterior lateral line system in one of the common benthic species, Trematomus bernacchii. Frequency-response and threshold-tuning curve methods yield similar functional characterizations of single afferent fibre responses to vibrational stimulation. Curve fitting of generalized transfer function to frequency-response curves allows an objective splitting of responses into velocity and acceleration sensitive populations thought to correspond to superficial and canal neuromasts, respectively. Both response types are characterized by a low-pass frequency-response curve, with a relatively low upper frequency cut-off when compared with data from temperate species. The sensitivity of the lateral line system of T. bernacchii is comparable to that of the mottled sculpin Cottus bairdi.


Fibers innervating different parts of the lateral line system of an Antarctic notothenioid, Trematomus bernacchii, have similar frequency responses, despite large variation in the peripheral morphology. Regional differences in the architecture and size of lateral line canals and neuromasts were measured in an Antarctic fish, Trematomus bernacchii, and the data were used in models of canal and cupular mechanics to predict the frequency response of these two peripheral structures. These modeled predictions were then compared to frequency response functions measured with single unit recording techniques from anterior and posterior lateral line fibers innervating different canals on the head and trunk of fish of various sizes. Despite large variations in the peripheral morphology of head and trunk canals in fish of different sizes, lateral line fibers were relatively homogeneous in their frequency response properties. In response to stimuli of equal pk-pk acceleration levels, all canal neuromast fibers responded with equal and maximum responsiveness in the 10-45 Hz range, after which responsiveness fell off at about 18 dB/octave. Whereas the biomechanical models of cupular and canal responsiveness predicted the region of equal and maximum responsiveness in the 10-45 Hz range, they did not predict the high frequency cutoff nor the slope. Rather, these models predicted responsiveness out to at least 540 Hz, and a high frequency slope of 12 dB/octave. In terms of the frequency response of peripheral fibers, we conclude that (1) there can be considerable morphological variability, with little consequence for function, as long as some minimum standards for maintaining constant acceleration responsiveness in the 10-45 Hz range are met, and (2) there must be additional filters between the cupula and primary afferent fibers.


Immunohistochemical study of the development of serotoninergic neurons in the brain of the brook trout Salvelinus fontinalis. Serotonin is believed to play an important role in the neuronal development of various invertebrates and mammals, but only one study has yet investigated the development of serotoninergic neurons in the brain of a teleost. In the present study, we investigate the development of serotoninergic neurons in the brain of the brook trout, Salvelinus fontinalis, by immunohistochemistry, from fertilisation to the resorption of the yolk sac and in juveniles for reference. Maintaining trout embryos and larvae in 9L:15D or in complete darkness made no difference in the appearance and distribution of serotonin immunoreactive (5-HTir) neurons. On day 56, the first 5-HTir perikarya, indicative of the primordia of the nuclei raphe medialis/dorsalis, have stained in the presumptive isthmus region. At hatching time (days 95-115), all the 5-HTir nuclei reported in the juvenile are present, except for the population observed in the lobus inferior hypothalami. We observed that the nucleus recessus lateralis stained on day 58, the raphe caudal nucleus on day 60, the nuclei raphe pallidus and obscurus on day 65, the area praetectalis on day 80, and the nucleus recessus posterioris and the anterior group of the nucleus recessus lateralis on day 92. At the complete resorption of the yolk sac (days 175-190), the nucleus reticularis paragigantocellularis, the nuclei raphe pallidus and obscurus and the caudal raphe of the brainstem are very weakly immunoreactive, and in juveniles, only one caudal immunoreactive nucleus is still present. A comparison of our result with those previously reported in the three-spined stickleback, Gasterosteus aculeatus, suggest a similar distribution of 5-HTir neurons in the brain of both species but also reveal species differences in the sequence of appearance of 5HT immunoreactivity in the different neuronal populations.


Quantitative histological study of the optic nerve in species of minnows (Cyprinidae, Teleostei) inhabiting clear and turbid water. Quantitative analysis of the optic nerve of minnows using light- and electron microscopy demonstrated that anatomical characteristics of the visual system are closely related to habitat turbidity. Species in the genera Notropis and Cyprinella inhabiting predominantly clear water had larger eyes and almost twice as many optic nerve fibers compared to minnows of turbid habitats. No differences were detected in the thickness of myelination, the axon diameter profile, or the number of optic nerve fibers per retinal area, indicating that the relative number of fibers, as well as their anatomical characteristics, are similar in all species and independent of habitat turbidity. It is therefore hypothesized that quantitative differences in the number of visual elements available for sampling and processing in the retina, optic nerve, and optic tectum are sufficient to account for presumed differences in visual performance.


Variation of tectal morphology in teleost fishes. The morphological organization of the optic tectum was analyzed in a number of divergent teleost species. Particular attention was focused on the organization of the periventricular gray zone and of afferent and efferent fiber systems within or adjacent to it. A dorsal part of the periventricular gray zone is recognized which is in register with the distribution of tangentially and radially oriented fascicles. A lateral part of the periventricular gray can be identified as being lateral to the lateral-most of the tangentially and radially oriented fascicles and being in register with a large number of circular fascicles in the deep white zone. Circular fascicles pass between the lateral part of the periventricular gray and a more ventral part. There are few if any circular fascicles in the part of the deep white zone that is in register with the ventral part of the gray. These parts of the periventricular gray are most clearly apparent in clupeomorph fishes, due to an exaggerated separation related to the presence of two tectal lobes within the hemisphere. It is hypothesized that the dorsal part of the gray, as can be recognized cytoarchitectonically, is in register with the projection of the dorsal optic tract and that the lateral and ventral parts of the gray are in register with the projection of the ventral optic tract.


Characteristics of saccades induced by neck torsions: a re-examination in the normal guinea pig. Torsion of the neck relative to the fixed head results in several reflexes involving the eyes, the neck and the body. One of these reflexes, the cervico-ocular reflex, has been described as having a small gain in the normal animal. However, when the body of a guinea pig is moved relative to the fixed head with a ramp-like velocity profile, saccades are systematically elicited in the direction of body movement. We re-examined the characteristics of this reflex in the normal guinea pig and demonstrated that: (1) it occurs mainly in the range of high velocity body movements; (2) the latency of the saccades is shorter than previously suspected; (3) the saccades are triggered at specific positions relative to the starting and ending positions of rotation, revealing some degree of flexibility in the reflex. We hypothesize that these saccades of nuchal origin are under the control of the same neuronal circuit as visually triggered saccades and quick phases of vestibular nystagmus. Thus, this nuchal reflex may fundamentally subserve orienting behaviour in normal animal.


Paradoxical analgesia produced by naloxone in diabetic mice is attributable to supersensitivity of delta-opioid receptors. The effects of naloxone on the analgesic response were examined using the tail-flick test, in mice with streptozotocin-induced diabetes. Subcutaneous injection of naloxone (5 mg/kg, s.c.) produced a marked analgesia in diabetic mice but not in age-matched non-diabetic mice. Naloxone-induced analgesia in diabetic mice was significantly reduced by pretreatment with naltrindole (0.1 mg/kg, s.c.), a selective antagonist of delta-opioid receptors. By contrast, no significant naloxone-induced increase in tail-flick latency in diabetic mice was observed after chronic treatment with naloxone (5 mg/kg, s.c.) for 5 days. However, the tail-flick latency was significantly increased by chronic treatment with naloxone in non-diabetic mice. Furthermore, the significant naloxone-induced increase in tail-flick latency in non-diabetic mice that had been chronically treated with naloxone was also antagonized by pretreatment with naltrindole. Chronic pretreatment with 5 mg/kg of naloxone for 5 days markedly attenuated the analgesic effect of the delta-agonist DPDPE in diabetic mice, whereas this pretreatment significantly enhanced the effect of DPDPE in non-diabetic mice. These results suggest that naloxone-induced 'paradoxical' analgesia in mice may be mediated predominantly by delta-opioid receptors.


Effect of amygdaloid kindling on [3H]dopamine and [14C]acetylcholine release from rat prefrontal cortex and striatal slices. The involvement of the dopaminergic (DA) systems in the control of limbic kindled seizures is ill defined. The effects of kindling on DA activity may have been overlooked in the past, because of its subtle unilateral occurrence and/or the variance of the endogenous imbalance of DA activity in normal animals. In the present study rats were screened for their endogenous DA imbalance using amphetamine-induced rotational behaviour. Electrical or sham kindling was applied in the hemisphere with the higher endogenous DA activity. Sections of the bilateral prefrontal cortex and dorsal and ventral striatum were dissected either 2 hours or 21 days after the final seizure and the electrically stimulated release of [3H]DA and [14C]acetylcholine (ACh) determined. Release was also measured in the presence of quinpirole or sulpiride to assess the activity of pre- and postsynaptic DA D2-receptors. Long-term effects of kindling consisted of facilitation of ACh release in the ventral striatum contralateral to the kindled amygdala and bilateral depression of DA release in the prefrontal cortex. Kindling therefore produced area specific changes in neurotransmitter systems giving rise to increased pro-convulsive cholinergic activity in the ventral striatum and decreased anti-convulsive dopaminergic activity in the prefrontal cortex.


Neural sensitivity to pentylenetetrazol convulsions in inbred and selectively bred mice. In these experiments, sensitivity to the convulsant drug pentylenetetrazol (PTZ) was measured in 10 inbred mouse strains, and in 4 mouse lines selectively bred for severe (WSP1, WSP2) or minimal (WSR1, WSR2) ethanol withdrawal convulsions. Using a timed infusion procedure, sensitivity to convulsions was assessed by measures of latency to convulsion, effective dose (ED) infused at time of convulsion, and brain concentration (BC) of PTZ at time of convulsion. In addition, ED and latency to convulsion were measured in WSP and WSR mice at 5 different concentrations of PTZ. Higher concentrations, which increased rate of drug infusion, reduced latency but had little effect on ED. WSP1 mice were slightly more sensitive to PTZ than WSR1 mice, but WSP2 mice were equally or less sensitive than WSR2 mice. Among the inbred strains, latency, ED and brain PTZ concentration were found to be highly correlated, suggesting that pharmacokinetic factors do not significantly influence access of PTZ to sites of action in the central nervous system. The C57BL/6J strain was least sensitive by all measures, while DBA/2J mice were highly sensitive. The BALB/cJ strain was the most sensitive strain as assessed by ED and latency, but BC indicated relatively average sensitivity. Apparently, pharmacokinetic factors in this strain result in a relatively rapid accumulation of drug in brain, making it appear to be more sensitive. Thus, although ED provides a reliable estimate of neural sensitivity in general, genetic factors exist which, in some strains, modify access of PTZ and possibly other drugs to brain, potentially affecting determination of sensitivity in the absence of a measure of brain drug concentration.


Impaired learning and memory in mature spontaneously hypertensive rats. In very old, normotensive rats, a disorganization occurs selectively in the retrosplenial cortex, and a similar disorganization occurs in this area in spontaneously hypertensive rats (SHR) at a much earlier age. Since this breakdown compromises a neural circuit involved in learning and memory, this study tests the hypotheses that these functions are disturbed in mature SHR and that they can be prevented or attenuated by long-term, anti-hypertensive therapy. SHR and Sprague Dawley rats (SD) at 3- and 12 months of age, and a group of SHR that had been normotensive from 3 to 12 months of age (CAP-SHR) were trained on an 8 arm radial maze task. Of the 12-month-old groups, SD reached criterion earliest (28 +/- 2 days) and made the least number of total errors. In comparison, 12-month-old SHR took significantly longer to reach criterion (39 +/- 2 days) and made nearly twice as many total errors. CAP-SHR were intermediate between the other two groups (32 +/- 2 days). Three-month-old SD learned the task at the same rate as the 12-month-old SD. In contrast, 3-month-old SHR learned the task significantly faster (21 +/- 1 days) and with fewer errors than any other group. These data indicate that, in SHR, learning and memory are compromised by 12 months of age, and that anti-hypertensive therapy with captopril partially prevents this decline.


Influence of medial septal cholinoceptive cells on c-Fos-like proteins induced by soman. The effects of intraseptal application of atropine on c-fos proto-oncogene expression related to soman treatment were studied by immunohistochemistry for c-Fos-like proteins. In control rats, 2 h after the onset of convulsion, c-Fos-like immunoreactivity was intense in the piriform and entorhinal cortices, but also in the cingulate, frontoparietal and retrosplenial cortices. In addition, the staining was moderate in the hypothalamus, amygdala and fascia dentata. The intraseptal application of atropine, which prevented soman-induced convulsions, reduced or even blocked c-Fos-like protein production related to soman treatment. This inhibition of Fos induction was significant in most of the limbic structures but also in non-limbic areas. The data in this study strongly suggest that the cholinergic cells of the medial septal area play a key role in soman-induced seizures, and confirm that c-Fos-like protein induction is closely related to neuronal hyperactivity.


Perinatal hypoxic ischemic encephalopathy affects the proportion of GABA-immunoreactive neurons in the cerebral cortex of the rat. The hypothesis was tested whether perinatal hypoxic ischemia leads to a preferential degeneration of the GABAergic inhibitory neurons in the cerebral cortex which, in turn, could account for the reported higher risk of developing epilepsy later in life. To that end rat pups, aged 12-13 days, were made hypoxic by employing a combination of unilateral ligation of one of the carotid arteries and a 90-min exposure to 8% O2. After recovery periods of 3, 7, 35 and 150 days, the animals were sacrificed by perfusion fixation and the brains embedded in Epon. Transverse semi-thin sections were alternately stained with an antibody against GABA and with Toluidine blue. By using an unbiased morphometric method (the disector) the number of GABA-immunoreactive (GABA-IR) neurons and the total number of nerve cells per unit volume of tissue were estimated in corresponding neocortical areas in the ipsilateral (damaged) and contralateral ('control') hemisphere. For all animals with post-ischemic survival times of 3 and 7 days GABA-IR cells constituted a lower proportion of the total number of nerve cells in the damaged than in the 'control' cortical areas. This finding was consistent with the outcome of an earlier in vitro study. By contrast, in all animals with a survival time of 35 and 150 days, the proportion of GABA-IR neurons was higher on the damaged than on the 'control' side. This switch in the direction of the left/right differences, apparently depending on the length of the post-ischemic survival time, was statistically significant. No lateralization in the proportion of GABA-IR cells was detected in the cerebral cortex of the control rats. These observations, therefore, do not support the hypothesis that perinatal hypoxic ischemia ultimately leads to a preferential loss of GABAergic neurons in the cerebral cortex.


Gravitoinertial force level affects the appreciation of limb position during muscle vibration. Illusory motion and displacement of the restrained forearm can be elicited by vibrating the biceps brachii or triceps brachii muscle. We measured the influence of gravitoinertial force level on these perceptual responses to vibration during parabolic flight maneuvers where normal (1G) and high force (1.8G) background levels alternated with microgravity (0G). Subjects indicated the apparent forearm position of the vibrated arm with the other forearm and also made verbal reports. Biceps brachii vibration induced illusory extension of the forearm and triceps brachii, illusory flexion; these apparent motions and displacements were highly G force-dependent being enhanced at 1.8G and diminished at 0G relative to normal 1G force level. These alterations are discussed in terms of vestibulo-spinal and propriospinal influences on alpha-gamma motoneuronal control of muscle tone and the varying requirements for postural load support in different force backgrounds. Their implications for the control and appreciation of limb movements during exposure to different G force levels are also described.


Lesions of the nucleus paragigantocellularis alter ex copula penile reflexes. The effects of electrolytic lesions of the rostral nucleus paragigantocellularis (nPGi) were examined on ex copula sexual reflexes in male rats. Bilateral lesions of the nPGi significantly reduced (by 50%) the onset of the first ex copula reflex, which usually was a glans erection. In addition, the number of dorsiflexions (flips) was significantly increased. In the anesthetized spinally intact rat the urethrogenital reflex cannot be evoked. However, after chronic bilateral lesions of the rostral nPGi, half of the rats tested displayed the urethrogenital reflex prior to section of the spinal cord. These data support a role for the rostral nPGi in the descending inhibition of male sexual reflexes.


Histamine H1 receptors in UC-11MG astrocytes and their regulation of cytoplasmic Ca2+. Experiments were carried out on UC-11MG human astrocytoma cells, a continuous cell line that expresses a broad range of the biochemical and electrophysiological properties found in well-differentiated astrocytes. Because of a number of recent reports that astrocytes may express receptors for a variety of neuro-active substances, we measured the effects of 12 different neurotransmitters on intracellular free Ca2+ (Ca2+i) in UC-11MG cells. Of these neurotransmitters only histamine was found to have a significant effect. Further characterization of the nature of the histamine response showed that UC-11MG cells express mepyramine-sensitive H1 receptors the activation of which causes both mobilization of Ca2+ from intracellular stores and entry of Ca2+ from the extracellular solution. No evidence was found for the presence of H2 receptors. The Ca2+i response was maximal at 300 microM histamine and was attenuated by increasing cell density. We suggest that this neurotransmitter may play a role in astrocytic function in the human CNS.


Histamine stimulates glycogenolysis in human astrocytoma cells by increasing intracellular free calcium. Astrocytes from a variety of sources, including the human UC-11MG astrocytoma line, express receptors for histamine on their plasma membranes, but the function of these receptors is largely unknown. Here we report studies on the effect of histamine on newly synthesized glycogen in the human astrocytoma-derived cell line, UC-11MG. We have found [3H]glycogen hydrolysis with a EC50 of 2 microM and a maximum effect of 30% at 300 microM histamine. The glycogenolytic effect of histamine was completely blocked by the H1 receptor antagonist, mepyramine, and was insensitive to the H2 receptor antagonist, cimetidine. Histamine-induced glycogenolysis was significantly reduced in the absence of extracellular Ca2+ and the residual response could be accounted for by Ca2+ released from intracellular stores. The Ca2+ ionophore, ionomycin, induced a similar concentration-dependent increase in both intracellular Ca2+ concentration and in glycogenolysis. These results suggest that one function of astrocytic histamine receptors in vivo may be the stimulation of glucose release from astrocytes, and that this process is mediated by increased intracellular free Ca2+. The glycogenolytic effect of histamine and other neurotransmitters in different systems, and the possible implication of astrocytic glycogenolysis in the pathophysiology of ischemia are discussed.


The striatopallidal projection displays a high degree of anatomical specificity in the primate. The striatopallidal projection in the squirrel monkey (Saimiri sciureus) was studied with two highly sensitive anterograde tracers, the lectin Phaseolus vulgaris leucoagglutinin (PHA-L) and biocytin. After small PHA-L injections into various sectors of the striatum, the striatopallidal projection was found to display a very precise topographical organization. Fibers from the head of the caudate nucleus emerge as several distinct fascicles that penetrate the dorsal portion of the pallidum at various points along its rostrocaudal extent. Each fascicle arborizes into the dorsal third of the pallidum as dense plexuses composed of numerous fibers that closely entwined the dendrites of pallidal neurons, hence forming typical 'woolly' fiber arrangements. In contrast, fibers from the postcommissural putamen emerge as a few compact bundles that reach the pallidum through its lateral surface. In the pallidum, thin fibers detach themselves from these compact bundles, sweep caudally, and arborize in the form of narrow and elongated bands aligned parallel to the medullary laminae. Each band appears composed of numerous, thin and weakly varicose fibers that make only en passant type of contact with pallidal cell bodies rostrally, but form a dense field of woolly fibers caudally. In cases in which two PHA-L injections were made at two different rostrocaudal levels in the putamen, two rostrocaudally distant fields of woolly fibers, separated one another by thin varicose fibers, occur in each band. Furthermore, each PHA-L injection site in the striatum gives rise to at least two bands in each pallidal segment, indicating that the primate striatum has a dual representation at pallidal level. Finally, injections of PHA-L and biocytin into two small and mediolaterally adjacent areas of the postcommissural putamen lead to the formation of two clearly distinguishable sets of bands in each pallidal segment. Even though they lie very close to one another these two types of bands never really overlap. This experiment shows that, in contrast to previous beliefs, axons of striatal neurons from two small adjacent populations do not converge upon the same pallidal neurons but instead project to several distinct subsets of pallidal neurons. The findings of the present study reveal that the striatopallidal projection system in primates is highly ordered and displays a high degree of specificity with respect to its target sites in the pallidum. Different anatomical strategies are used to maximally exploit the relatively small pallidal space and ensure that the finely tuned corticostriatal information is not blurred as it flows through the funnel-shaped pallidum.


Nerve growth factor effects on pyridine nucleotides after oxidant injury of rat pheochromocytoma cells. Neurotrophic factors regulate neuronal survival and neurite growth in development and following injury. Oxidative stress produced in neurons as a consequence of primary injury, or during reperfusion following ischemia, may contribute to cell death. Here, the effects of nerve growth factor (NGF) on the response to H2O2 injury were examined in the PC12 rat pheochromocytoma cell line. Specifically, the effect of NGF on cell viability after H2O2 injury was measured. Pretreatment with NGF enhanced survival after H2O2 treatment, as measured by Trypan blue dye exclusion, radiolabeled amino acid incorporation, tetrazolium salt reduction, or cytoplasmic enzyme release. One early event associated with H2O2 treatment was a rapid decrease in NAD+. Although initial decreases in NAD+ levels were similar in control and NGF-treated cells, the latter recovered more rapidly and extensively. The decline in total NAD observed after NGF treatment was almost equal in magnitude to the measured increase in NADP. Inhibition of poly(ADP-ribose) polymerase also enhanced viability following H2O2 injury. Treatment with both NGF and an inhibitor of this enzyme resulted in a greater reduction of H2O2 toxicity than was observed with either agent alone. These data suggest that NGF protection is multifactorial and that a significant component of the NGF effect is due to its regulatory role in the metabolism of pyridine nucleotides.


Central carbachol stimulates vasopressin release into interstitial fluid adjacent to the paraventricular nucleus. We have used an in vivo double microdialysis probe technique in conscious rats to determine whether the application of carbachol to one paraventricular nucleus (PVN) can result in increased local release of vasopressin from that PVN. Experiments were carried out 24 h after placement of microdialysis probes lateral to each PVN. When both probes were perfused initially with 0.9% NaCl, vasopressin was detected in the outflow (dialysate) from both probes. When carbachol (100 micrograms/ml) was included in the perfusate of one probe for the first 10 min of a 30-min collection period, while the other probe continued to be perfused with saline alone, there was a seven-fold increase in the concentration of vasopressin in the dialysate from the carbachol-perfused probe; the vasopressin concentration in the dialysate from the contralateral probe increased only slightly. The plasma vasopressin concentration was also elevated. When one of the paired probes was perfused with carbachol (100 micrograms/ml) for 30 min, there were similar increases in the concentration of vasopressin in the dialysate from both probes and a sustained increase in the plasma vasopressin concentration. Thus, vasopressin is released into the interstitial fluid adjacent to the PVN under basal conditions, and this release can be substantially increased when vasopressin secretion to the periphery is stimulated.


Morphology of central terminations of intra-axonally stained, low-threshold mechanoreceptive primary afferent fibers from oral mucosa and periodontium in the rat. Horseradish peroxidase (HRP) was injected intra-axonally into functionally identified primary afferent fibers within the rat spinal trigeminal tract in order to study the morphology of their central terminations. They were physiologically determined to be large, myelinated afferent fibers from periodontium or oral mucosa by means of electrical and mechanical stimulation of their receptive fields. Twenty-eight axons that innervated the periodontium of incisors and 21 axons that innervated the oral mucosa were stained for distances of 2-5 mm from the injection sites at the levels of the main sensory nucleus (Vms), spinal trigeminal nucleus and rostral cervical spinal cord. The collaterals of these primary afferent fibers formed terminal arbors in the medial or dorsomedial part of the Vms, and the oral and interpolar spinal trigeminal nuclei (Vo and Vi). In the caudal spinal trigeminal nucleus (Vc), the collaterals of one half of the periodontium afferent fibers terminated mainly in lamina V at the rostral and middle levels of Vc. On the other hand, the collaterals of the other half of the periodontium afferent fibers terminated mainly in lamina IV at the rostral level of Vc, and rostrally these terminal areas shifted to the most medial part of Vi. The collaterals of mucosa afferent fibers terminated in lamina V at the rostral level of Vc, and these terminal areas shifted gradually to laminae III and IV as the parent axons traveled more caudally. These shifts were staggered rostrocaudally according to the rostrocaudal locations of the receptive fields. The density of collaterals of periodontium afferent fibers in Vi was significantly larger than that of mucosa afferent fibers. The average size of the varicosities of periodontium afferent fibers was significantly larger than those of mucosa afferent fibers in Vo, Vi and Vc. The average number of varicosities belonging to single collaterals of slowly-adapting periodontium afferent fibers in Vi were significantly larger than those in Vo. In Vi, the average number of varicosities of single collaterals of slowly-adapting periodontium afferent fibers were significantly larger than those of rapidly-adapting periodontium afferent fibers.


5-HT3 receptor antagonists fail to block the suppressant effect of cocaine on the firing rate of A10 dopamine neurons in the rat. In the present study, we have shown that cocaine is significantly more potent in suppressing the firing rate of dopamine cells in the ventral tegmental area (VTA or A10) than in the substantia nigra pars compacta (SNC or A9). We have also determined the ability of several 5-HT3 receptor antagonists to alter the electrophysiological response of A10 dopamine neurons in the rat to cocaine, as these compounds have been implicated in modulating the effects of drugs of abuse on the dopamine system. It was found that the 5-HT3 receptor antagonists ICS205-930, zacopride and ondansetron do not alter either the firing rate or cocaine-induced suppression of the basal firing rate of A10 dopamine cells.


Involvement of nucleus accumbens dopamine in the motor activity induced by periodic food presentation: a microdialysis and behavioral study. Two experiments were undertaken to investigate the role of accumbens dopamine (DA) in food-related motor activities. Although presentation of large amounts of food elicits feeding behavior, periodic food presentation (PFP; e.g. a 45-mg pellet every 45 s) induces considerable locomotion, rearing and other motor activities in food-deprived rats. In the first experiment, in vivo microdialysis methods were used to study DA release and metabolism in the nucleus accumbens of behaving rats exposed to periodic food presentation. Four behavioral conditions were used: high rate of PFP (one pellet per 45 s), low rate of PFP (one pellet per 4 min), massed food presentation and food deprivation control. The rats that received a high rate of PFP showed substantial increases in locomotor activity, and also showed significant increases in extracellular DA and DA metabolites. Rats that received massed presentation of food pellets consumed large quantities of food, but showed no significant increases in locomotor activity or DA release. Although the group that received the high rate of PFP showed the highest motor activity and the largest increase in DA release, there was only a modest correlation (r = 0.34) between motor activity and increased DA release. In the second experiment, the neurotoxic agent 6-hydroxydopamine (6-OHDA) was injected into the nucleus accumbens in order to assess the effects of DA depletion of PFP-induced motor activity. DA depletion significantly reduced PFP-induced motor activity in the first week after surgery, but by the second week DA-depleted rats had recovered normal levels of motor activity.(ABSTRACT TRUNCATED AT 250 WORDS)


Low concentrations of penicillin partially suppress CA3 hippocampal IPSPs in vitro. Low concentrations of penicillin (50-300 IU/ml) produce a pro-convulsant state in CA3 hippocampus characterized by low amplitude, low frequency (2-3 Hz) spontaneous field potential oscillations. Evoked field potentials were used to demonstrate that this distinct, coordinated behavior of the hippocampal neuronal network which is intermediate between normal activity and fully synchronized epileptiform bursting is the result of partial blockade of GABAA-mediated IPSPs. A new method for estimating the degree of IPSP block relative to convulsant doses of penicillin (2,000 IU/ml) indicates that the half-maximal effect occurs at 300 IU/ml. Fully synchronized bursts may require almost complete IPSP block.


A single restraint stress exposure potentiates analgesia induced by intrathecally administered DAGO. In rats, restraint exposure potentiates the magnitude and duration of analgesia following both the peripheral and intracerebroventricular administration of several opioid agonists as compared to non-stressed controls. It has been suggested that the site of action whereby restraint leads to potentiated opioid analgesia is located supraspinally. However, the possible contribution of spinal analgesic mechanisms also warrants investigation. Thus, the purpose of the present study was two-fold: (1) to determine whether a single exposure to restraint stress would result in the dose-dependent potentiation of analgesia following the intrathecal (i.t.) administration of the mu (mu)-receptor selective opioid agonist [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin (DAGO) and (2) to quantify the degree of analgesia in restrained vs. non-restrained rats using the tail-flick and hot-plate analgesic assays. Using rats implanted with chronic i.t. cannula, dose- and time-course curves were observed following the i.t. administration of DAGO. The results demonstrate that both the duration and magnitude of analgesia was significantly potentiated in restrained rats compared to non-restrained controls. Restraint-treated rats receiving 0.15-0.6 micrograms of DAGO i.t. showed 1.3-1.5-fold potentiation of analgesia in the tail-flick assay and a 2.3-5.6-fold potentiation using the hot-plate assay. Restraint immobilization potentiated the magnitude and duration of DAGO-induced analgesia administered by the i.t. route as measured by the tail-flick and hot-plate assays. These data suggest that spinal analgesic mechanisms significantly contribute to the enhanced analgesic potency of opioids in subjects exposed to restraint stress.


Nitric oxide modulates NMDA-induced increases in intracellular Ca2+ in cultured rat forebrain neurons. We studied the effects of nitric oxide (NO) and the NO-releasing agents sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP) and isosorbide dinitrate (ISDN) on N-methyl-D-aspartate (NMDA)-induced increases in intracellular Ca2+ ([Ca2+]i), whole-cell patch-clamp currents and on glutamate-stimulated [3H]dizocilpine binding. NO and agents that release NO partially inhibit increases in [Ca2+]i at concentrations between 1 microM and 1 mM. These agents also decrease [Ca2+]i changes produced by kainate and potassium, but to a smaller extent. As the effects of NO are still present following alkylation of the redox modulatory site on the NMDA receptor this action of NO is probably not a consequence of oxidation of the redox site. In contrast to SNP, ISDN does not inhibit NMDA-induced whole cell patch-clamp currents suggesting that NO modulates [Ca2+]i via perturbation of a Ca2+ homeostatic process. Furthermore, SNP may have a direct action on the NMDA receptor complex in addition to the generation of NO. 8-Bromo-cGMP does not mimic the inhibitory effect of NO suggesting that this effect is not the result of NO stimulation of neuronal cGMP production. As the production of NO in neurons is dependent on increases in [Ca2+]i associated with NMDA receptor activation, these data suggest that NO-mediated decreases in [Ca2+]i may represent a novel feedback inhibitory mechanism for NO production in the brain.


Presence of D-alanine in proteins of normal and Alzheimer human brain. This report constitutes the first demonstration of the presence of D-alanine in the proteins of the human nervous system. Proteins of the frontal lobe white and gray matter of human brains, both normal and Alzheimer subjects, contain D-alanine at concentrations between 0.50 and 1.28 mumol/g of wet tissue, 50-70-times lower than the concentration of L-alanine. Both white and gray matter of Alzheimer brains contain D-alanine 1.4-times higher than the respective regions of normal brains. The gray matter proteins of Alzheimer brains show a highly significant 8% decrease in total alanine content, when compared with normal brain gray matter proteins. Since Alzheimer's disease is exhibited by deterioration of the gray matter, the occurrence of elevated D-alanine levels in the gray matter of Alzheimer brains is a significant discovery and raises the question whether this enantiomer causes the degeneration of the gray matter proteins in Alzheimer's disease, or whether it is an effect of the disease.


Regeneration of neural lobe-like neurovascular contact regions in explanted neural lobes placed in the hypothalamo-neurohypophysial tract in the lateral retrochiasmatic area. Neural lobes that had been explanted 30 days earlier were transplanted into retrochiasmatic lesions of the hypothalamo-neurohypophysial tract 15 days before being observed by electron microscopy and neurophysin immunohistochemistry. Neurovascular contact regions consisting of microvascular networks surrounded by neurophysin-immunoreactive terminals developed in 86% of the grafted explants. The fine structure of such regions resembled that of the neural lobe, with palisades of neurosecretory axon terminals abutting the basal laminae associated with the microvessels and plexuses of neurosecretory axons occupying the spaces within the vascular network. Both continuous and fenestrated blood vessels were present. Lamellopodia from glial cells partially ensheathed both axons and terminals, and sometimes separated the terminals from the perivascular basal lamina. Profiles in which neurosecretory granulated vesicles were depleted and many microvesicles were present were interpreted as terminals from which hormones had been released. No regeneration occurred into explants that had been cryotreated to kill their pituicytes and other cells before transplantation. These observations demonstrate that neurosecretory axons served in the hypothalamus can regenerate to form a new neural lobe-like structure when an appropriate microenvironment is available, and that neural lobes explanted 21 days earlier retain the elements required to supply that microenvironment. They also provide evidence that viable pituicytes are essential for regeneration of neurosecretory axons and terminals into transplanted explants.


Iron and transferrin uptake by brain and cerebrospinal fluid in the rat. Iron and transferrin uptake into the brain, CSF and choroid plexus, and albumin uptake into the CSF and choroid plexus, were determined after the intravenous injection of [59Fe-125I]transferrin and [131I]albumin into control rats aged 15, 21 and 63 days and 21-day iron-deficient rats. Iron uptake by the brain was unidirectional, greatly exceeded that of transferrin and was equivalent to 39 and 36% of the plasma iron pool per day in the 15-day control and 21-day iron-deficient rats. The rate of transferrin catabolism in the rats was only about 20% of the plasma pool per day. Iron and transferrin uptake into the brain and CSF decreased with increasing age and was greater in the iron-deficient than in the control 21-day rats. The quantity of 125I-transferrin recovered in the CSF could account for only a small proportion of the iron taken up by the brain. Albumin transfer to the CSF also decreased with age but was lower than that of transferrin and was not affected by iron deficiency. Similarly, the plasma: CSF concentration ratios of transferrin and albumin, as determined immunologically, decreased with age and were greater for transferrin than albumin. It is concluded that iron uptake by the brain is dependent on iron release from transferrin at the cerebral capillary endothelial cells with recycling of transferrin to the plasma and transfer of the iron into the brain interstitium. Only a small fraction of the transferrin bound by brain capillaries is transcytosed into the brain and CSF, this being one source of CSF transferrin while other sources are local synthesis and transfer from the plasma by the choroid plexuses.


Saturable uptake of [125I]L-triiodothyronine at the basolateral (blood) and apical (cerebrospinal fluid) sides of the isolated perfused sheep choroid plexus. The uptake of 125I-labelled L-triiodothyronine (T3) was measured on the blood side of the isolated perfused choroid plexus of the sheep using steady-state and single-circulation paired tracer techniques. The steady-state uptake of T3 was 33.5% (perfusion fluid protein content was 0.05 g.dl-1) which could be reduced to 9.4% in the presence of 500 microM unlabelled T3 showing partial saturation. The CSF to blood steady-state [125I]T3 measurements gave plasma/CSF ratio, R%, of 24.6 +/- 4.8% which was reduced to 9.8 +/- 2.1% in the presence of 500 microM unlabelled T3 in the mock CSF. The transport of T3 across the blood face of the choroid plexus and the CSF to blood transport, failed to show sodium dependence. Using the single circulation paired tracer technique, the initial uptake in less than 60 s, Umax of [125I]T3 was 50.4 +/- 3.9% relative to the extracellular marker [3H]D-mannitol. However, when 250 microM unlabelled T3 was present, Umax was reduced by 66%, although further significant inhibition at higher concentrations was not observed. Uptake of T3 at the blood side of the choroid plexus was partially saturated in the presence of unlabelled reverse T3 and DT3, suggesting little uptake stereospecificity. Unlabelled thyroxine (T4) and the amino acid analogues cycloleucine (aminocyclopentane-1-carboxylic acid) and BCH (beta-2-aminobicyclo-[2,2.1]-heptane-2-carboxylic acid) each reduced [125I]T3 uptake significantly, but not to the same degree as T3 stereoisomers. The neutral amino acids alanine and phenylalanine, had no effect on uptake.(ABSTRACT TRUNCATED AT 250 WORDS)


Behavior of VRG neurons during the atonia of REM sleep induced by pontine carbachol in decerebrate cats. The microinjection of carbachol into the pons of acute decerebrate cats elicits a REM sleep-like atonia and a profound suppression of respiratory motoneuronal activity (J. Appl. Physiol., 69 (1990) 2280-2289). To assess whether this suppression is mediated by medullary neurons that provide respiratory drive to motoneurons of the respiratory pump muscles (diaphragm and intercostals), we studied the effect of pontine carbachol on the activity of neurons of the ventral respiratory group (VRG) in decerebrate, vagotomized, paralyzed and artificially ventilated cats. VRG neurons were recorded extracellularly along with the activity of phrenic and intercostal (external and internal) nerves. Both inspiratory (I) and expiratory (E) VRG neurons had incrementing, ramp-like bursts of activity during their firing periods and were not vagal motoneurons. Carbachol produced a depression of the peak firing rate in most (42/57) neurons studied. However, five cells showed no change and ten had an increase in activity in spite of consistent depression at the motoneuronal level. For the total population of cells (34 I and 23 E), the peak firing was reduced to 88.5% +/- 16.3 (S.D.) of control. The simultaneously recorded phrenic activity was reduced to 77.9% +/- 11.5, while inspiratory intercostal activity fell to 63.4% +/- 21.6 and expiratory to 23.2% +/- 21.2 of control. The carbachol-induced changes in peak firing of both I and E cells were quantitatively similar, and positively correlated to changes in peak phrenic activity. Analysis of this correlation suggested that phrenic and intercostal activities will be depressed to some degree by carbachol even when the average VRG cell activity remains unchanged. In addition, our data show that VRG cells may receive a combination of inhibitory and excitatory inputs during the carbachol-induced depression of respiratory motoneurons. Thus, although some disfacilitation from VRG cells may occur, there must be additional inhibitory or disfacilitatory pathways that mediate the decrease in activity of both phrenic and intercostal motoneurons that accompanies the REM sleep-like atonia.


Graded postischemic reoxygenation reduces lipid peroxidation and reperfusion injury in the rabbit spinal cord. The effect of graded postischemic reoxygenation on lipid peroxidation, neurological recovery and the degree of spinal cord damage after 20 min abdominal aorta ligature was tested in the rabbit. In comparison with normoxic recirculation, the graded postischemic reoxygenation (GPIR) during early phase of reperfusion (30 min) significantly reduced the level of lipid peroxidation products (LPP) in vivo and in vitro after 1 h survival. Neuropathological changes in animals with normoxic reperfusion showed gradual deterioration ranging from appearance of heavy argyrophilic neurons after 1 h reperfusion followed by neuronal necroses after 12 h survival to the development of an extensive spongy lesion reaching ventral horn and intermediate zone 2 days postoperatively. The neuroprotective effect of graded postischemic reoxygenation was evident even after 2 days survival with preserved structural integrity of the gray matter as confirmed by light and electron microscopy. The results indicate that graded postischemic reoxygenation during 1 h reperfusion can reduce lipid peroxidation and suppress irreversible neuronal damage using developing during the early reperfusion phase.


Effects of calcium on the dynamic process of transmitter release which generates either skew- or bell-MEPPS. Miniature endplate potential (MEPP) amplitudes, MEPP frequencies and ratios of skew:bell-MEPPs were determined as well as synaptic vesicle diameters and densities at the mouse diaphragm neuromuscular endplate during exposure to elevated calcium concentrations. Additions of external Ca2+ had variable effects on MEPP frequencies and percentages of skew-MEPPs, regardless of concentrations used (1-25 mM). Nevertheless, changes in MEPP amplitudes were most sensitive (4-fold decrease) to low value increases of Ca2+. Changes in MEPP frequencies produced by an increase in Ca2+ were very sensitive to initial frequencies as well as the initial calcium concentration. An increase in Ca2+ usually increased MEPP frequency (providing skew-MEPPs were measured). Changes in the percentage of skew-MEPPs were extremely variable (4-90%) and these changes depended on initial frequencies, initial skew- to bell-MEPP ratios and age of the mouse. With a change in Ca2+ concentration, synaptic vesicle diameters and densities remained constant during changes in MEPP frequencies and large changes in the skew:bell-MEPP ratios; and, vesicle numbers were sometimes slightly increased. Because of the wide range in MEPP frequencies and amplitudes, this study demonstrates that the effect of various treatments should be evaluated on identified endplates and that analyses of randomly selected endplates must consider the large variability between endplates. These results show that the skew-MEPP class must not be ignored in studies of spontaneous MEPP release, and that initial frequencies and age of the mouse are also important in evaluating changes in skew-MEPP to bell-MEPP ratios. The rapid changes in skew- to bell-MEPP classes indicate that MEPP class and size are determined at the moment of release by the state of the release process as proposed by Kriebel et al. (1990). Because changes in calcium concentration can immediately alter the ratio of skew- to bell-MEPPs we conclude that the release process has two states to generate the two classes of MEPPs, and that the release process is very sensitive to conditions so that states are easily changed. We propose that the release process meters transmitter in subunit amounts to form both classes of MEPPS and that the calcium ions modulate the process.


Hippocampal activity, olfaction, and sniffing: an olfactory input to the dentate gyrus. Experiments in freely moving rats showed that olfactory stimuli elicit a burst of rhythmical 15-30 Hz waves in or near the hilus of the dentate gyrus but not in adjacent regions of CA1. This fast wave burst is not elicited by visual, auditory, or somatosensory inputs and is not related to motor activity. Electrical stimulation of the olfactory bulb evokes a complex potential in the hilus of the dentate gyrus but not in adjacent regions of CA1. Experiments making use of wave-triggered averaging demonstrated that there is a degree of phase-locking between (a) hippocampal RSA and sniffing or other respiratory patterns, (b) hippocampal RSA and the initiation of jumping, and (c) respiration and the initiation of jumping. An early hypothesis that the hippocampus and dentate gyrus are part of an olfacto-motor mechanism may merit re-examination.


N-methyl-D-aspartate and vasopressin activate distinct voltage-dependent inward currents in facial motoneurones. Facial motoneurones of the rat respond to arginine vasopressin by generating a voltage-dependent inward current which is sodium-dependent and is resistant to tetrodotoxin. In the present study, we have investigated the action of N-methyl-D-aspartate (NMDA) on these same neurones. We have obtained single-electrode voltage-clamp recordings from brainstem slices of newborn rats. In a majority of vasopressin-sensitive facial motoneurones, NMDA induced an inward current. This action was direct, was concentration-related and could be suppressed by the specific competitive antagonist D-2-amino-5-phosphopentanoic acid (D-AP5). The NMDA-evoked current increased in amplitude as the neuronal membrane was depolarized. It could be blocked by the noncompetitive antagonist MK-801. It was potentiated following removal of extracellular magnesium, and was attenuated or suppressed when the external magnesium concentration was increased from 1 to 10 mM. By contrast, none of these treatments affected the vasopressin-induced current. These results show that facial motoneurones in the rat possess functional NMDA receptors and indicate that NMDA and vasopressin affect the bioelectrical properties of these neurones by turning on distinct voltage-dependent inward currents.


Isradipine is able to separate morphine-induced analgesia and place conditioning. The effect of isradipine, a dihydropyridine calcium antagonist, on morphine-induced place preference and analgesia in rats and mice was studied. Isradipine (0.6-5.0 mg/kg s.c.) inhibited an acquisition of morphine-induced place preference in rats and mice in a dose-related manner. Isradipine did not affect or strengthen morphine-induced analgesia as measured by tail-clip and hot-plate tests in mice and tail-clip and tail-flick tests in rats. The results suggest that analgesic and reinforcing effects of morphine might be pharmacologically separated by isradipine.


Calbindin D-28k and choline acetyltransferase are expressed by different neuronal populations in pedunculopontine nucleus but not in nucleus basalis in squirrel monkeys. Single- and double-immunostaining procedures were used to study the distribution of the acetylcholine synthesizing enzyme choline acetyltransferase (ChAT) and the calcium binding protein calbindin D-28k in the nucleus basalis of Meynert (nbM) and in the pedunculopontine nucleus (PPN) of the squirrel monkey (Saimiri sciureus). As expected from previous studies in other primates, including humans, the nbM in the squirrel monkey is enriched with large ChAT-immunoreactive neurons that form clusters in the substantia innominata. Some ChAT-positive neurons are also scattered more dorsally within the internal and external medullary laminae of the pallidal complex. A smaller number of calbindin-immunoreactive cells occur in the same locations and their mean cross-sectional somatic area (424 microns 2) is not significantly different from that of the ChAT-immunoreactive cells (450 microns 2). Furthermore, 60% of the ChAT-immunopositive cells in the nbM display calbindin immunoreactivity. Most of these double-immunoreactive neurons occur in the typical clusters of the nbM, whereas the large neurons scattered in between the clusters display ChAT immunoreactivity only. In the PPN, ChAT-positive neurons are scattered around and partly within the superior cerebellar peduncle and also form a dense cluster in the lateral portion of the mesopontine tegmentum. Calbindin-immunoreactive cells also abound around the superior cerebellar peduncle, but they are more sparsely distributed and cover a larger sector of the tegmentum than the ChAT-positive neurons. These calbindin-immunoreactive cells are significantly smaller (200 microns 2) than the ChAT-immunoreactive cells (471 microns 2) and no double-immunostained neurons are present in the PPN.(ABSTRACT TRUNCATED AT 250 WORDS)


Sex differences of hypothalamic prolactin cells develop independently of the presence of sex steroids. There is evidence for a hypothalamic prolactin (PRL) system that expresses sexually dimorphic traits. The aim of this in vitro study is to gain an insight into the process of sexual differentiation of hypothalamic PRL cells. In particular, we wanted to determine whether sexual differentiation of these cells can occur independently of the surge of gonadal testosterone which, in the male rat embryo, takes place at embryonic day (E) 18 and is commonly believed to start the critical period of sexual differentiation of the brain. Gender-specific cell cultures were prepared from E 14 or E 17 rat diencephalon and raised in the absence of gonadal steroids. After 10 days in vitro, numbers of PRL-immunoreactive (IR) cells and PRL levels were quantified by immunocytochemistry and Western blotting, respectively. Numbers of PRL-IR cells and PRL levels were 2-3 times higher in cultures prepared from female than from male embryos of either age. It is concluded that sexual differentiation of hypothalamic PRL cells starts well before the generally acknowledged onset of the critical period and may proceed independently of the action of gonadal testosterone. Besides gonadal steroids, other mechanisms, such as cell-intrinsic realization of a sex-specific genetic program, may be responsible for initiating the development of sexually dimorphic neuronal phenotypes.


Activation of the dentate gyrus by pentylenetetrazol evoked seizures induces mossy fiber synaptic reorganization. Kindled seizures evoked by electrical stimulation of limbic pathways in the rat induce sprouting and synaptic reorganization of the mossy fiber pathway in the dentate gyrus (DG). To investigate whether seizures evoked by different methods also induce reorganization of this pathway, the distribution of mossy fiber terminals in the DG was examined with Timm histochemistry after systemic administration of pentylenetetrazol, a chemoconvulsant that reduces Cl- mediated GABAergic inhibition. Myoclonic seizures evoked by subconvulsant doses of pentylenetetrazol (24 mg/kg i.p.) were not accompanied by electrographic seizures in the DG, and did not induce mossy fiber sprouting. Generalized tonic-clonic seizures evoked by repeated administration of PTZ (24 mg/kg i.p.) were consistently accompanied by electrographic seizure activity in the DG, and induced sprouting and synaptic reorganization of the mossy fiber pathway. The results demonstrated that repeated generalized tonic-clonic seizures evoked by pentylenetetrazol induced mossy fiber synaptic reorganization when ictal electrographic discharges activated the circuitry of the DG.


Effects of 1,3-di-o-tolylguanidine (DTG), a sigma ligand, on local cerebral glucose utilization in rat brain. The 2-deoxy-D-[1-14C]glucose ([14C]DG) method was used to examine the effects of the relatively selective sigma ligand 1,3-di-o-tolylguanidine (DTG) on cerebral metabolism in freely moving rats. Each animal received an i.p. injection of DTG (0.2, 1, or 5 mg/kg) or normal saline 20 min prior to the infusion of [14C]DG. DTG induced dose-dependent changes in local cerebral glucose utilization (LCGU) in several motor and limbic structures. Most structures showed increases in LCGU, with a maximum effect at 1 mg/kg. The most profound increases in LCGU were observed in brain regions that are rich in sigma receptors. These included cerebellar and related nuclei (interpositus, lateral and medial cerebellar n., vestibular n., olivary n.), ambiguus n., superior colliculus (superior layers), hippocampus (CA2, CA3, DG), n. basalis of Meynert interpeduncular n., and the substantia nigra pars compacta and pars reticulata. No significant decreases in glucose utilization were observed at any dose. Although the areas affected by DTG are similar to those previously reported for other sigma ligands, future studies employing a range of doses for additional selective sigma ligands must be carried out in order to confirm whether these changes in LCGU were sigma-mediated.


High molecular weight basic fibroblast growth factor-like protein is localized to a subpopulation of mesencephalic dopaminergic neurons in the rat brain. A rabbit antiserum (R917) was raised to a purified fraction of bovine brain basic fibroblast growth factor (bFGF). On Western blots of rat midbrain extract, the antiserum did not recognize low molecular weight forms of bFGF. Instead, it recognized a single band of 27-28 kDa. Immunohistochemically, the antiserum preferentially stained a subpopulation of calbindin-negative mesencephalic dopaminergic neurons. The positive somata were mainly packed in a ventral portion of the tegmentum including the A10 region, the ventral tegmental area and the pars compacta of the medial substantia nigra, but were also scattered in both the pars compacta and reticulata portions of the lateral substantia nigra. Processes of dendrites and axons were clearly visible. Terminal fields were located in striosomes, the dorsolateral rim of the neostriatum, the anterodorsal aspect of the nucleus accumbens shell, the infralimbic cortex, and the medial prefrontal cortex. These results suggest that trophic specialization in subpopulations may occur in all three of these dopaminergic projection systems, i.e. the nigrostriatal, mesolimbic and mesocortical pathways.


Anticonvulsant effect of intranigral fluoxetine. Bilateral focal injections of the serotonin uptake inhibitor, fluoxetine (1.75-7.0 nmol) into substantia nigra (SN) protected against convulsive seizures evoked by the focal injection of bicuculline methiodide into area tempestas, an epileptogenic site within the deep prepiriform cortex. Injection of fluoxetine unilaterally in SN or bilaterally into a site dorsal to SN was not anticonvulsant. Blockade of nigral gamma-aminobutyric acid (GABA) receptors with bicuculline in SN did not reverse the anticonvulsant action of intranigral fluoxetine. These data suggest that serotonergic transmission in SN exerts a seizure suppressing action which is independent of GABA transmission in SN.