The corpus spongiosum penis pressure and external penile muscle activity in the goat during coitus

Abstract

A needle tipped catheter was implanted in the corpus spongiosum penis (CSP) of mature male goats to determine the pressure during coitus. Electromyographic (EMG) electrodes were also implanted in the ischiocavernosus (IC) muscles and bulbospongiosus (BS) muscles to monitor their activity. During coitus, the mean peak CSP pressure was 1031 mm Hg and this peak occurred during the ejaculatory thrust immediately after the peak corpus cavernosum penis pressure. Anesthesia of the BS muscles significantly reduced the peak CSP pressures of the coital period; however, it did not change the normal, precoital and postcoital pressures. The EMG activity of the BS muscles was in phase with CSP pressure peaks.