The broad objective of this study is to use genetic and induced animal models of neuronal ceroid-lipofuscinosis (NCL) to shed new light on the biochemical basis of the different forms of NCL in humans. Because of the unavailability of appropriate human tissues at carefully defined stages of the disease, as well as possible pathological changes due to autolysis prior to autopsy, the ability to perform in-depth studies at different ages makes these animal models very attractive. Interesting leads developed as a result of such studies can be tested for their applicability to the human forms of the disease. It is noteworthy that the two biochemical findings that have stood up to extensive scrutiny were both originally obtained in animal models: elevated dolichyl oligosaccharides were first described in NCL dogs, and the storage of mitochondrial ATPase subunit c was first described in ovine NCL. However, the relation of these findings to the observed Pathology is unclear at present. Brain tissue and cultured neurons will be studied for immunoreactivity with an antibody to subunit c, which will be made in rabbits. We propose to use natural and induced animal models of NCL, as well as cultured primary rat neurons, to search for an underlying lesion in vesicular transport between the endoplasmic reticulum and the Golgi compartments. We will test whether there is an accumulation of dolichyl oligosaccharides in brain from a canine model for juvenile NCL as a function of disease progression. We will carry out a similar study in rat brain after prolonged intracranial infusion of thiol protease inhibitors or inhibitors of glycoprotein processing. We will also study the effect of protease inhibitors and inhibitors of vesicular transport and glycoprotein processing at the level of individual cells using primary neuronal cell cultures. Dolichyl oligosaccharides will be isolated by lipid extraction, digested with endoglucosaminidase H and analyzed by high performance liquid chromatography. The integrity of the Golgi apparatus in cultured neurons will be studied by localization of Golgi markers at the light microscopic and electron microscopic levels. Better diagnostic techniques and elucidation of the biochemical disturbance in the neuronal ceroid lipofuscinoses should facilitate carrier identification and could lead to a decrease in the prevalence of this group of disorders.