Regulation of Female Rat Sexual Motivation in Olfactory Nervous System

在这个项目中，我们通过两种行为测试范式来研究雌性大鼠性动机的神经内分泌机制，即配对交配(交配测试中雌性可以躲避的地方)和伴侣偏好(雌性更喜欢性行为活跃的雄性而不是不活跃的雄性的气味)。杏仁内侧核的射频损伤消除了伴侣的偏好，并缩短了在步速交配测试中接触雄性性伴侣的潜伏期。相比之下，内侧视前损害消除了伴侣的偏好，而不影响起搏行为，而外侧隔病变使他们的步伐更快，但不影响伴侣的偏好。这些结果表明，已知的控制前凸的前脑结构可能在雌性大鼠性动机的调节中发挥不同的作用。第二，我们研究了性腺类固醇对雄性和雌性大鼠对同种气味偏好的影响。性欲活跃的雄鼠偏好接受性欲强的雌鼠的气味，而不喜欢雄性和去卵巢的雌鼠的气味(阳性型)，而发情期的雌鼠则喜好性活跃型的雄虫的气味而不喜欢去势的雌鼠的气味(女性型)。男性和女性的性腺切除都消除了所有的偏好。虽然对去势的女性用睾酮治疗恢复了女性的偏好模式，但对去势的男性用雌激素和孕激素治疗激活了女性的偏好模式，但不是男性的偏好模式。这表明，男性的偏好模式是由雄激素调节的，而女性的偏好模式是由雌激素和/或黄体酮调节的。在女性接受雄激素治疗后，没有出现变性模式，这表明正常女性没有男性模式的神经回路，因为她们在围产期缺乏雄激素暴露。需要进一步的研究来阐明这一机制。

In this project, we investigated the neuroendocrine mechanisms of sexual motivation in female rats by means of two behavioral test paradigms, paced mating (mating test with an escapable place for females) and partner preference (females prefer odors of sexually active males rather than those of inactive one). Radiofrequency lesions in the medial amygdala eliminated partner preference and shortened latency to access sexual males in paced mating test. In contrast, medial preoptic lesions eliminated partner preference without effect on pacing behavior, whereas lateral septal lesions made their pace faster but did not affect partner preference. These results suggest that the forebrain structures that have been known to control lordosis may play different roles in the regulation of sexual motivation in female rats.Secondly, we examined effects of gonadal steroids on preference of conspecific odors in male and female rats. Sexual active males preferred odors of receptive females rather than those of males and ovariectomized females (masculine pattern), while estrous females preferred odors of sexually active males than those of females and orchidectomized males (feminine pattern). Gonadectomy in both males and females eliminated all the preference. Although treatment with testosterone to castrated females restored the feminine pattern of preference, treatment of estrogen and progesterone to castrated males activated the feminine pattern, but not the masculine pattern, of preference. These suggest that the masculine pattern of preference is regulated by androgen, whereas the feminine pattern is regulated by estrogen and/or progesterone. No transsexual pattern appeared after androgen treatment in females suggests that normal females have no neural circuits for the masculine pattern because of a lack of androgen exposures in their perinatal periods. Further studies are required to elucidate this mechanism.