射精相关的神经生理机制研究进展

Neurophysiological mechanisms of ejaculation

雄性动物性行为是一个连续而有序的过程,最终以射精伴有性满足而结束。其中射精过程受到各级射精中枢的广泛调控,生殖器感觉信号通过传入纤维传至脊髓射精中枢,再通过传出纤维上行至脑干及前脑,后者将整合后的信息通过下行纤维传至脊髓射精中枢,进而调控射精发生的时机及场合。信号沿脊髓上传,传递至相互关联的丘脑、下丘脑、边缘系统以及大脑皮层,并与嗅觉信号相互整合。上述区域均与射精有关,但其促进或抑制射精发生的确切机制尚未阐明。在控制脊髓射精中枢的上游机制中,内侧视前核及脑干均参与其中,其中内侧视前核已明确与射精所伴随的性快感有关。同时,一些神经递质参与射精过程并在其中起到重要作用。本文就射精神经生理通路及相关神经递质加以综述,拟进一步了解射精相关发生机制,为研究及治疗射精相关疾病提供理论依据。

The sexual behavior of the male can be described as a series of behavioral transitions eventually leading to ejaculation and sexual satisfaction. The ejaculation itself is extensively regulated by different ejaculation generators. The " spinal ejaculation generator" receives genito-sensory signals through afferent fibers and then informs the brainstem and forebrain via ascending fiber projections. Conversely,the supraspinal areas restrict ejaculations to the optimal moments and circumstances through descending afferent fibers. The messages ascending from the spinal cord reach the interconnected thalami,hypothalami,limbic system and cerebral cortex and are integrated with olfactory information. These brain areas are all related to ejaculation,but the exact facilitatory and inhibitory mechanisms involved have not yet been elucidated hitherto. Both the medial preoptic nucleus and brainstem areas play an important role in the " downward" mechanisms underlying the spinal " release" of an ejaculation. The medial preoptic nucleus is also precisely related to the " sexual rewarding" coming with an ejaculation. Meanwhile,the roles of several neurotransmitters are discussed considering their remarkable effects on ejaculation. This review focuses on the ejaculation-related circuits and neurotransmitters for the purpose of gaining a deeper insight into the mechanisms of ejaculation and providing some theoretical evidence for the study and treatment of ejaculation-related diseases.