Abstract:
Sexual stimulation triggers changes in female physiology and behavior, including sexual satiety and preparing the uterus for pregnancy. Serotonin (5-HT) is an important regulator of reproductive physiology and sexual receptivity, but the relationship between sexual stimulation and 5-HT neural activity in females is poorly understood. Here, we investigated dorsal raphe 5-HT neural activity in female mice during sexual behavior. We found that 5-HT neural activity in mating females peaked specifically upon male ejaculation and remained elevated above baseline until disengagement. Artificial intravaginal mechanical stimulation was sufficient to elicit increased 5-HT neural activity but the delivery of ejaculatory fluids was not. Distal penis expansion (\"penile cupping\") at ejaculation and forceful expulsion of ejaculatory fluid each provided sufficient mechanical stimulation to elicit 5-HT neuron activation. Our study identifies a female ejaculation-specific signal in a major neuromodulatory system and shows that intravaginal mechanosensory stimulation is necessary and sufficient to drive this signal.
摘要:
性刺激会引发女性生理和行为的变化,包括性饱腹感和准备子宫怀孕。5-羟色胺(5-HT)是生殖生理和性接受的重要调节因子,但是女性性刺激与5-HT神经活动之间的关系知之甚少。这里,我们研究了雌性小鼠在性行为过程中的背侧中缝5-HT神经活性。我们发现,交配雌性中的5-HT神经活动在雄性射精时特别达到峰值,并且在脱离之前保持高于基线。人工阴道内机械刺激足以引起5-HT神经活性增加,但射精液的输送却不能。射精时的阴茎远端扩张(“阴茎拔罐”)和射精液的强力排出均提供了足够的机械刺激以引起5-HT神经元激活。我们的研究确定了主要神经调节系统中女性射精特异性信号,并表明阴道内机械感觉刺激对于驱动该信号是必要且足够的。