Characteristics of ongoing and reflex discharge of renal postganglionic neurons

Characteristics of basal and reflex firing of single renal postganglionic fibers are reviewed to ascertain whether subpopulations of renal neurons can be distinguished. Moreover, characteristics of renal neurons are contrasted with those of sympathetic neurons innervating vascular and nonvascular tissues of the spleen and small intestine. Attempts to distinguish functional subtypes of renal neurons based on their responses to excitatory or inhibitory influences led to no clear conclusions. Responses of the renal population of neurons differed from those of the splenic and mesenteric populations of postganglionic neurons. Our findings provided no concrete answers about the neural mechanisms by which different functions of the kidney may be regulated selectively. This question continues to require careful and insightful investigation.