Laboratorio de Comportamiento Reproductivo, Escuela de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Tlaxcala, Av. Universidad No. 1, Col. La Loma Xicohtencatl, Tlaxcala 90000, Mexico.
J Sex Med. 2009 Nov;6(11):3045-55. doi: 10.1111/j.1743-6109.2009.01470.x.
A spinal pattern generator controls the expression of ejaculation. When this ejaculation generator is activated it can be phasically controlled, at a spinal level, by intrinsic mechanisms that eventually lead to the establishment of both short- and long-lasting inhibitory processes.
To evaluate the hypothesis that endogenous opioids participate in the control of ejaculation by exerting an inhibitory influence upon the spinal generator for ejaculation.
Electromyographic recordings of the ejaculatory motor pattern recorded in the bulbospongiosus muscles were obtained as physiological markers of ejaculation.
By using a model for the study of ejaculation in spinal male rats, we analyze the effects of the intravenous injection of the opioid agonist morphine and the opioid antagonist naloxone on the expression of the ejaculatory motor pattern. In addition, the effect of pre-treatment with systemic naloxone on the establishment of the inhibition of the ejaculatory motor pattern resulting from its repeated sensory-induced elicitation was evaluated.
Data obtained show that: (i) the i.v. injection of morphine (1-10 mg/rat) inhibits whereas that of naloxone (1-10 mg/rat) induces the expression of the genital ejaculatory motor pattern; (ii) naloxone pretreatment dose-dependently blocks the inhibitory effects of the high dose of morphine upon the rhythmic motor pattern of ejaculation; (iii) the inhibition of the ejaculatory response induced by repeated urethral stimulation can be delayed, and the ejaculatory capacity augmented, by naloxone injection (10 mg/rat).
Together, these evidences support the notion that endogenous opioids modulate the activity of the spinal generator for ejaculation by exerting an inhibitory influence.
脊髓模式发生器控制射精的表达。当这个射精发生器被激活时，它可以在脊髓水平上通过内在机制进行阶段性控制，这些内在机制最终导致建立短暂和持久的抑制过程。
评估内源性阿片肽通过对射精脊髓发生器施加抑制影响来参与射精控制的假说。
记录球海绵体肌的射精运动模式的肌电图记录作为射精的生理标志物。
通过使用脊髓雄性大鼠射精研究模型，我们分析了静脉注射阿片类激动剂吗啡和阿片类拮抗剂纳洛酮对射精运动模式表达的影响。此外，还评估了全身纳洛酮预处理对重复感觉诱发引起的射精运动模式抑制建立的影响。
获得的数据表明：（i）静脉注射吗啡（1-10mg/大鼠）抑制而纳洛酮（1-10mg/大鼠）诱导生殖器射精运动模式的表达；（ii）纳洛酮预处理剂量依赖性地阻断了吗啡高剂量对射精节律性运动模式的抑制作用；（iii）纳洛酮（10mg/大鼠）注射可延迟重复尿道刺激引起的射精反应的抑制，并增强射精能力。
这些证据共同支持内源性阿片肽通过施加抑制影响来调节脊髓射精发生器活动的观点。
