EVIDENCE FOR COEXISTENCE OF ATP AND NITRIC-OXIDE IN NONADRENERGIC, NONCHOLINERGIC (NANC) INHIBITORY NEURONS IN THE RAT ILEUM, COLON AND ANOCOCCYGEUS MUSCLE

The possible coexistence of the two non-adrenergic, non-cholinergic (N ANC) inhibitory neurotransmitters, adenosine 5'-triphosphate and nitri c oxide in the myenteric plexus was investigated using whole-mount pre parations of rat ileum, proximal colon and anococcygeus muscle. The pr esence of adenosine 5'-triphosphate in neurones was examined using the quinacrine fluorescence technique. After localizing and taking photog raphs of quinacrine-fluorescent neurones and nerve fibres, the same ti ssues were then fixed and processed for NADPH-diaphorase activity, a m arker for nitric oxide-containing neurones. We have demonstrated for t he first time that almost all quinacrine-fluorescent myenteric neurone s in the proximal colon are also NADPH-diaphorase reactive, while only a subpopulation of quinacrine-fluorescent neurones in ileum and anoco ccygeus muscle were also NADPH-diaphorase reactive.