NADPH DIAPHORASE INNERVATION OF THE RAT ANOCOCCYGEUS AND RETRACTOR PENIS MUSCLES

NADPH diaphorase histochemistry was used to determine whether the rat anoocccygeus (AC) and retractor penis (RP) muscles are innervated by n erves capable of synthesizing nitric oxide. In both tissues, muscle fa scicles were enclosed by a varicose plexus of NADPH diaphorase positiv e (ND+) fibers. Perikarya of neurons on the surface of the AC muscle w ere also intensely stained for NADPH diaphorase. Many AC-RP ganglion c ells in the pelvic plexus, located by the retrograde tracer Fluorogold , also stained for the enzyme. However, a significant population of AC -RP neurons in this location remained unstained. These results provide further evidence that nitric oxide may be an important neurotransmitt er in these tissues.