Neural regulation of ejaculation

Introduction. Delineation of the underlying neurophysiological mechanisms of ejaculatory behavior is crucial for the treatment of male sexual dysfunction, including premature ejaculation. Recent studies provide compelling evidence that a population of lumbar spinothalamic (LSt) cells may play a role in the regulation of the ejaculatory response. Subsequent to ejaculation, LSt cells exhibit markers of activation that are not only highly correlated with ejaculatory behavior, but are also absent following the expression of other components of sexual behavior, such as mounts or intromissions. Similarly, targeted chemical lesion of LSt cells using substance P-saporin abolishes ejaculatory behavior explicitly. Early evidence suggests that pharmacological manipulation of LSt cells may offer additional evidence of crucial LSt cell involvement in the generation of ejaculation. Aim. This review is intended to summarize what has currently been revealed regarding the role of LSt cells in the regulation and generation of ejaculatory behavior, and also to discuss the direction of future behavioral investigations. Methods. Information presented in this discussion was derived from analysis of numerous recent articles detailing the delineation of anatomical and physiological correlates of sexual behavior, as well as numerous literature searches using the National Library of Medicine PubMed Services. Results. A great deal of the work that has led to the implication of LSt cells in ejaculatory behavior is reviewed in the present article, including clinical data, as well as anatomical, physiological, and behavioral examinations. The rationale for ongoing pharmacological studies is also discussed. Conclusion. LSt cells appear to play a vital role in the generation and regulation of ejaculatory behavior. Additional elucidation of this "ejaculation generator" could prove invaluable for the future treatment of male sexual dysfunction. Studies are currently in progress to further reveal the precise function of these cells and mechanisms of action through which they operate.