Extensive distribution of NADPH diaphorase activity in the nerve supply of the cat lower urinary tract.
Nitric oxide is a neurotransmitter which causes smooth muscle relaxation and may contribute to this response in some regions of the lower urinary tract. In the present study the distributions of neurons and their axons which contain the synthetic enzyme for nitric oxide, nitric oxide synthase, were mapped by staining for NADPH diaphorase in sections of proximal urethra, bladder trigone and detrusor and whole mounts of vesical ganglia from cats. Stained axons were present in the smooth muscle of all regions of bladder and proximal urethra, but were most common in the urethra and least prevalent in the detrusor. Stained axons were also present in the mucosa; most of these were associated with blood vessels, but some travelled close to the epithelium. Stained mucosal axons were much more numerous in the proximal urethra than in any bladder region. Darkly stained neuronal somata were found throughout the vesical ganglia, where they appeared to comprise the majority of neurons. Small ganglia containing stained neurons were also found in sections of various urinary tract regions, where they were located in the serosa, between muscle layers and, in the urethra, also in the mucosa. These studies have shown an extensive distribution of neurons and axons that stain for NADPH diaphorase (and are predicted to synthesize nitric oxide) throughout all tissues of the cat lower urinary tract. It is hypothesized that nitric oxide is an inhibitory transmitter in the cat bladder and proximal urethra and may also have a role as a sensory transmitter in the mucosa of these regions.
Keast
J R
JR
Department of Physiology and Pharmacology, University of Queensland, Australia.
Kawatani
M
M
D000818:Animals; D001369:Axons / Q000201:enzymology; D002415:Cats; D005260:Female; D005726:Ganglia, Parasympathetic / Q000166:cytology / Q000201:enzymology; D006651:Histocytochemistry; D008297:Male; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology; D014521:Urethra / Q000201:enzymology / Q000294:innervation; D014551:Urinary Tract / Q000201:enzymology* / Q000294:innervation*
D009252:NADPH Dehydrogenase