Sympathectomy of the kidney results in which of the following responses?
The kidney is innervated primarily by the sympathetic nervous system and as such, regulates the contraction of the smooth muscle surrounding the afferent and efferent aerioles of the glomerulus. Sympathetic stimulation to the efferent glomerular aerioles causes the constriction and increases the filtration rate, leading to an increase in urinary output. Similarly, with the loss of sympathetic innervation, such as due to sympathectomy of the kidney, relaxation of tone of the afferent aerioles occurs and the filtration rate increases which results in an increased urine output. Decreased urine output may result from the restriction of the afferent aerioles, leading to a decrease in glomerular filtration rate. Ref: Eaton D.C., Pooler J.P. (2009). Chapter 1. Renal Functions, Anatomy, and Basic Processes. In D.C. Eaton, J.P. Pooler (Eds), Vander's Renal Physiology, 7e.
No change to the glomerular filtration rate, nor to the urine output
Decreased urine output
Reduction of glomerular filtration rate and decreased urinary output
Increased urine output