The spinal pattern generator for ejaculation

Ejaculation is the physiological process that describes the expulsion of the semen from the urethra. This physiological response is a remarkably sophisticated phenomenon that requires the participation of several stereotyped motor patterns for its expression and when taking place, it starts a constellation of short- and long-lasting physiological and behavioural processes. Little is known about the neural mechanisms accounting for its activation. It has been recently proposed that a central pattern generator located at the spinal level is involved in the control of ejaculation. The aim of this paper is to review the evidence supporting this notion. Thus, the mechanics of ejaculation, its anatomical substrates and innervation are described. Besides, evidence from behavioural, physiological and pharmacological studies that support the existence of an intraspinal rhythm modulating the ejaculatory response are provided. Data are discussed in the context of the physiology of male sexual function. (C) 2007 Elsevier B.V. All rights reserved.