NADPH-DIAPHORASE AND OTHER NEURONAL MARKERS IN NERVES AND GANGLIA SUPPLYING THE GUINEA-PIG VAS-DEFERENS

Enzyme histochemistry, in combination with immunohistochemistry was us ed to establish the neurochemistry of neurons in the vas deferens and pelvic ganglia of the guinea-pig. Nerve fibres characterised by reacti vity for reduced nicotinamide adenine dinucleotide phosphate (NADPH)-d iaphorase reactivity formed a dense network in the lamina propria and circular muscle layer of the vas deferens, but were very sparse in the longitudinal muscle layer of the vas deferens. NADPH-diaphorase react ivity was also present in nerve fibres forming a dense perivascular pl exus in many of the arteries in the pelvic region and in some of the e ndothelial cells, especially near the origin of the capillaries. Nerve s with vasoactive intestinal polypeptide (VIP)-immunoreactivity had a similar distribution to NADPH-diaphorase reactive nerves. Tyrosine hyd roxylase (TH)-immunoreactive nerve fibres were found in both muscle la yers of the vas deferens. There was no coexistence of VIP- and TH-immu noreactivities in nerve fibres in the vas deferens. In the anterior pe lvic ganglia, the origin of the nerve fibres in the vas deferens, seve ral classes of neurons could be identified by the presence or absence of the reactivity for NADPH-diaphorase and immunoreactivity for VIP an d TH. Neurons containing both VIP and NADPH-diaphorase reactivity acco unted for 40% of neurons in the ganglia. Neurons with VIP-immunoreacti vity but not NADPH-diaphorase reactivity accounted for 6%. TH-immunore active neurons accounted for 22% of neurons in the anterior pelvic gan glia. Very rare cells (< 1%) contained both VIP- and TH-immunoreactivi ties. The remaining neurons, which were not labelled by any of these m arkers, comprised 31% of neurons in anterior pelvic ganglia. These res ults demonstrate the existence of NADPH-diaphorase reactivity in neuro ns containing VIP-immunoreactivity, thus suggest that nitric oxide may be a neurotransmitter in guinea-pig vas deferens, especially in the c ircular muscle layer, in the arteries, and in other pelvic organs inne rvated by pelvic ganglia.