Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Department of Andrology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China.
J Sex Med. 2020 Apr;17(4):614-622. doi: 10.1016/j.jsxm.2020.01.006. Epub 2020 Feb 7.
Although abnormal sympathetic nerve system (SNS) activity has been demonstrated in the pathogenesis of ejaculation disorders, few data are available on its underlying mechanism.
To investigate whether differences in ejaculatory behavior of rats were associated with the state of SNS activity and gamma-aminobutyric (GABA) receptor expressions in the paraventricular nucleus (PVN) of the hypothalamus and the effects of GABA receptors in the PVN on ejaculatory behavior.
Based on ejaculatory performance, Sprague-Dawley rats were divided into "sluggish," "normal," and "rapid" ejaculators. PVN microinjection was performed to evaluate the role of GABA receptors on sexual behavior.
The outcomes include differences in expression and distribution of GABA receptors and norepinephrine level among the 3 groups and changes in copulation behavior parameters after PVN microinjection.
Compared with "normal" rats, the "rapid" group ejaculated more times with shorter latency (P < .001, P < .001) and had lower expression and distribution of both GABA-A and GABA-B receptors, while the opposed results appeared in the "sluggish" group. The norepinephrine level was successively increased among "sluggish," "normal," and "rapid" rats (P < .001) and correlated with ejaculation frequency (r = 0.896, P < .001) and ejaculation latency (r = -0.835, P < .001). In addition, bilateral microinjection of the GABA-A and GABA-B receptor agonist (isoguvacine and baclofen) into the PVN both significantly prolonged the intromission latency and inhibited ejaculation, which could be blocked by antagonist gabazine and CGP-35348, respectively. Vigabatrin, the GABA-transaminase inhibitor, caused a significantly reduced ejaculation frequency and extended ejaculation latency in rats, which could be offset by simultaneous injections of gabazine and CGP-35348.
Our findings provide new understanding about GABA receptors in the PVN on sexual behavior and enhance the comprehension of neurobiological mechanisms involved in premature ejaculation.
STRENGTHS & LIMITATIONS: Our results have indicated that GABA receptors in the PVN may inhibit ejaculation through restraining the activity of SNS. However, our study did not analyze the changes of GABA receptors in other brain areas, which needs further study.
Ejaculation behaviors in male rats are associated with SNS activity and could be regulated by GABA receptors in the PVN, which may be of assistance in the treatment of ejaculation disorders in the future. Zhang QJ, Yang BB, Yang J, et al. Inhibitory Role of Gamma-Aminobutyric Receptors in Paraventricular Nucleus on Ejaculatory Responses in Rats. J Sex Med 2020;17:614-622.
尽管异常的交感神经系统（SNS）活动已被证明与射精障碍的发病机制有关，但关于其潜在机制的信息却很少。
研究大鼠射精行为的差异是否与下丘脑室旁核（PVN）中 SNS 活性和γ-氨基丁酸（GABA）受体表达的状态有关，以及 PVN 中的 GABA 受体对射精行为的影响。
根据射精表现，将 Sprague-Dawley 大鼠分为“缓慢”、“正常”和“快速”射精者。进行 PVN 微注射以评估 GABA 受体在性行为中的作用。
3 组大鼠之间 GABA 受体的表达和分布以及去甲肾上腺素水平存在差异，并且 PVN 微注射后交配行为参数发生变化。
雄性大鼠的射精行为与 SNS 活性有关，并且可以通过 PVN 中的 GABA 受体进行调节，这可能有助于将来治疗射精障碍。
