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Published on: April 23, 2018
Spinal Contusion Injury-Induced Ejaculatory Dysfunction Is Reduced by Intrathecal Infusions of Gastrin Releasing
Siddharth S Gaikwad1,2, Kiran Kumar Soni3,4, Tej Nakashe5
1Shirley Ryan Ability Lab, Chicago, IL, USA.
Purpose:
Spinal cord injury (SCI) has devastating effects on urogenital functions, including severe deficits in ejaculation. SCI treatment development is hindered by limited understanding of effects of SCI on the spinal ejaculation generator (SEG). The SEG consists of a population of lumbar spinothalamic (LSt) cells that control ejaculation. LSt cells control ejaculation via release of neuropeptides, notably gastrin releasing peptide (GRP). In control male rats, intrathecal infusions of GRP strongly facilitate ejaculatory reflexes, while GRP antagonists prevent ejaculation triggered by stimulation of the dorsal penile nerve (DPN). Moreover, ejaculatory dysfunction was associated with significantly reduced expression of GRP mRNA and protein in LSt cells. Here, we test the hypothesis that GRP infusions may restore ejaculatory reflexes in SCI males.
Materials And Methods:
In a first study, male Sprague Dawley rats received either controlled spinal contusion at 200 Kdynes (n=8) or sham treatment (n=8). Four weeks later, animals received an acute spinal transection to remove remaining supraspinal influence on the SEG and subsequent intrathecal infusions (10 µL) of Saline and GRP 20 to 29 (0.2 nmol) while parameters of ejaculatory reflexes were recorded. In addition, DPN was stimulated at frequencies that normally trigger ejaculation in control males (30 Hz) or subthreshold (5 Hz) and reflexes were recorded. GRP, but not Saline triggered ejaculatory reflexes and facilitated DPN-stimulated reflexes equally in Sham and SCI groups. In a second study, the procedures were repeated, but without the acute spinal transection prior to infusions. Again, GRP, but not Saline, triggered and facilitated ejaculatory reflexes with no differences between Sham and SCI groups.
Results:
These results indicate that a reduction of GRP in LSt cells following SCI may contribute to ejaculatory dysfunction.
Conclusions:
GRP may be a target for development of treatment options for sexual dysfunction following SCI.
