NADPH-DIAPHORASE REACTIVITY IN NERVES SUPPLYING THE RAT ANOCOCCYGEUS MUSCLE

NADPH-diaphorase histochemistry was used to establish the nature of ne urons and nerve fibers in the rat anococcygeus muscle. NADPH-diaphoras e-reactive nerve cell bodies were found in ganglia in the caudal dorsa l fascia of the muscle and within the muscle itself. The reactive nerv e cells had a relatively smooth surface and a single axon. They formed bundles of positive nerve fibers which entered the muscle and branche d further to form a network extending towards the cranial end. In addi tion, bundles of NADPH-diaphorase-reactive fibers of extrinsic origin joined the loose plexus of local bundles and microganglia. The NADPH-d iaphorase-reactive neurons supplying the rat anocoocygeus muscle provi de a neuroanatomical basis for the non-adrenergic non-cholinergic rela xation of the muscle mediated by nitric oxide.