Department of Molecular and Behavioral Neuroendocrinology, Institute of Zoology, University of Regensburg, 93053 Regensburg, Germany.
Horm Behav. 2010 Feb;57(2):222-9. doi: 10.1016/j.yhbeh.2009.11.006. Epub 2009 Dec 3.
Beneficial effects of sexual activity and mating on the responsiveness to environmental stress can be observed in humans and other mammalian species alike, but the underlying neurobiological mechanisms are largely unknown. Sexual activity and mating with a receptive female has recently been shown to reduce the subsequent emotional stress response via activation of the brain oxytocin system. Therefore, we investigated the neuronal and hormonal responses to an acute stressor (forced swimming) after mating in male rats. Attenuation of the stress-induced increase of c-fos and CRH mRNA expression within the hypothalamic paraventricular nucleus 4 h after mating revealed that sexual activity reduced neuronal reactivity in this region. However, this effect was independent of oxytocin as oxytocin receptor blockade, by central administration of an oxytocin receptor antagonist, after mating did not prevent the reduced expression of c-fos mRNA in response to stressor exposure. Mating itself stimulated corticotrophin (ACTH) and corticosterone secretion, which was absent in males after contact with an unreceptive female (non-mated group). However, ACTH and corticosterone responses to forced swimming applied either 45 min or 4 h after female contact were similar between mated and non-mated males. These findings provide evidence for a stress-protective effect of sexual activity and mating in male rats and for dissociation between neuronal and neuroendocrine stress responses.
性行为和交配对环境应激反应的有益影响在人类和其他哺乳动物中都可以观察到，但潜在的神经生物学机制在很大程度上尚不清楚。最近的研究表明，与接受的雌性进行性行为和交配可以通过激活大脑催产素系统来减少随后的情绪应激反应。因此，我们研究了雄性大鼠交配后对急性应激源（强迫游泳）的神经元和激素反应。交配后 4 小时，下丘脑室旁核内 c-fos 和 CRH mRNA 表达的应激诱导增加减弱表明，性行为降低了该区域的神经元反应性。然而，这种效应与催产素无关，因为在交配后中央给予催产素受体拮抗剂阻断催产素受体不会阻止应激暴露时 c-fos mRNA 表达的减少。交配本身会刺激促肾上腺皮质激素 (ACTH) 和皮质酮的分泌，而与不接受的雌性（未交配组）接触的雄性则没有这种分泌。然而，在雌性接触后 45 分钟或 4 小时应用强迫游泳时，交配和未交配雄性的 ACTH 和皮质酮反应相似。这些发现为雄性大鼠性行为和交配的应激保护作用提供了证据，并为神经元和神经内分泌应激反应的分离提供了证据。
