Histochemical demonstration of nerve cell bodies in the retractor penis muscle and the penile artery of the bull.

The presence of single nerve cell bodies and small ganglia in the retractor penis muscle and the penile artery of the bull was demonstrated by using antisera to neurofilament protein and neuron specific enolase. In the retractor penis muscle the findings were confirmed by staining for acetylcholinesterase. It was also shown that relaxation of strips of the retractor penis muscle induced by 70 microM acetylcholine was totally blocked by a 2.0 microM concentration of the ganglionic blocking drug chlorisondamine. The hypothesis is presented that the relaxation of the bovine retractor penis muscle and the bovine penile artery induced by nicotinic ganglionic stimulating drugs is at least in part mediated via receptors located on the nerve cell bodies described in this study.