NITRIC OXIDE SYNTHASE-CONTAINING NERVES AND GANGLIA IN THE DOG PROSTATE : A COMPARISON WITH OTHER TRANSMITTERS

The distribution of nitric oxide synthase immunoreactive nerves in the dog prostate was compared to the total innervation (as estimated by protein gene product 9.5 immunoreactivity), and to that of adrenergic (tyrosine hydroxylase-immunoreactive), cholinergic (acetylcholinesterase-positive), and some peptidergic nerves immunoreactive towards vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide, and helospectin. Clusters of ganglia with cell bodies containing acetylcholinesterase, or one of these six immunoreactive components, were found in the dorsal capsule. Coarse nerve trunks expressing these immunoreactive components extended from the ganglia, and divided into varicose terminals in the capsule and intraglandular smooth muscle strands, and gave off further branches, which surrounded acini and accompanied ducts. The labelling for nitric oxide synthase generally coincided with that for vasoactive intestinal peptide within cell bodies and nerves of various types. Cell bodies, nerve trunks and varicose terminals showing labelling for pituitary adenylate cyclase-activating peptide and helospectin were generally also labelled for vasoactive intestinal peptide. The innervation pattern suggests that nitric oxide may act in concert with vasoactive intestinal peptide and related peptides in the control of prostatic smooth muscle activity and secretion.