Neurobiology of PTSD: Effects on the spinal cord

Many men suffering from stress, including post-traumatic stress disorder (PTSD), report sexual dysfunction, which is traditionally treated via psychological counseling. Recently, we identified a gastrin-releasing peptide (GRP) system in the lumbar spinal cord that is a primary mediator for male reproductive functions. To ask whether acute severe stress could alter the male-specific GRP system, we used a single-prolonged stress (SPS), a putative rat model for PTSD. Exposure of male rats to SPS decreases both the local content and axonal distribution of GRP in the lower lumbar spinal cord and results in an attenuation of penile reflexes in vivo. Remarkably, pharmacological stimulation of GRP receptors restores penile reflexes in SPS-exposed males, and induces spontaneous ejaculation in a dose-dependent manner. Furthermore, although the level of plasma testosterone is normal one week after SPS exposure, there is a significant decrease in the expression of androgen receptor protein in this spinal center, which may make the spinal center less responsive to circulating androgens. We conclude that the spinal GRP system for male reproductive function is vulnerable to stress, which may provide new insights into clinical treatment of erectile dysfunction triggered by stress and psychiatric disorders.