Anatomical Science International

, Volume 86, Issue 1, pp 19–29

The gastrin-releasing peptide system in the spinal cord mediates masculine sexual function

Review Article

DOI: 10.1007/s12565-010-0097-z

Cite this article as:
Sakamoto, H. Anat Sci Int (2011) 86: 19. doi:10.1007/s12565-010-0097-z

Abstract

The lumbar spinal segments are of particular interest because they are sexually dimorphic and contain several neuronal circuits that are important in eliciting male sexual responses such as erection and ejaculation. Gastrin-releasing peptide (GRP) is a member of the bombesin-like peptide family first isolated from the porcine stomach. A collection of neurons in the lumbar spinal cord (L3–L4 level) of male rats projects to the lower lumbar spinal cord (L5–L6 level), releasing GRP onto somatic and autonomic centers known to regulate male sexual reflexes. All these target neurons express and localize specific receptors for GRP. This system of GRP neurons is sexually dimorphic, being prominent in male rats but vestigial in females. The system is completely feminine in genetically XY rats with a dysfunctional androgen receptor gene, demonstrating the androgen-dependent nature of the dimorphism. Pharmacological stimulation of GRP receptors in this spinal region remarkably restores sexual reflexes in castrated male rats. Exposure of male rats to a severe traumatic stress decreases the local content and the axonal distribution of GRP in the lumbar spinal cord and results in an attenuation of penile reflexes in vivo. Administration of a specific agonist for GRP receptors restores penile reflexes in the traumatic stress-exposed male rats. This review summarizes findings on this recently identified spinal GRP system, which may be vulnerable to stress, that controls male reproductive function. The identification of a male-specific neuronal system regulating sexual functions offers new avenues for potential therapeutic approaches to masculine reproductive dysfunction.

Keywords

Gastrin-releasing peptideLumbar spinal cordAndrogensMale sexual function

Copyright information

© Japanese Association of Anatomists 2010

Authors and Affiliations

  1. 1.Ushimado Marine Laboratory, Graduate School of Natural Science and TechnologyOkayama UniversitySetouchiJapan
  2. 2.Department of Anatomy and NeurobiologyKyoto Prefectural University of MedicineKyotoJapan