Significant physiological roles of ancillary penile nerves on increase in intracavernous pressure in rats: experiments using electrical stimulation of the medial preoptic area

The objectives of this work were to evaluate the contributions of the ancil lary penile nerves to penile erection in male rats in vivo. We investigated the effects of unilateral and bilateral transection of the cavernous nerve (main penile nerve) on the increase in intracavernous pressure (ICP) follo wing electrical stimulation of the medial preoptic area (MPOA) in male rats in vivo. Alter unilateral or bilateral transection of the cavernous nerve (main penile nerve), the ICP responses showed decreases of 28% and 55%, res pectively compared to those ICP responses before transection. In other word s, even after bilateral transection of the cavernous nerve, significant inc reases in the ICP response following central stimulation were observed. In contrast to these findings, the ICP response was completely eliminated foll owing bilateral pelvic nerve transection. These data suggested that the anc illary penile nerves, which originate from the major pelvic ganglia, have a complementary role to the cavernous nerves in the autonomic motor innervat ion of the penis.