National Institute of Mental Health, Laboratory of Clinical Sciences, Section on Comparative Studies of Brain and Behavior, Poolesville, Maryland 20837, USA.
J Neuroendocrinol. 1991 Apr 1;3(2):155-61. doi: 10.1111/j.1365-2826.1991.tb00258.x.
Abstract Previous studies have demonstrated that oxytocin receptors in specific nuclei of rat forebrain are regulated by gonadal steroids. The current study used in vitro receptor autoradiography to investigate the distribution and regulation of oxytocin receptors in the forebrain of the female prairie vole (Microtus ochrogaster). In contrast to rats, in female prairie voles gonadal steroid secretion and oestrus behaviour result from male chemosignal stimulation and ovulation is induced by mating. Thus, the prairie vole brain provides an opportunity for investigating links between environmental stimuli, gonadal steroids and oxytocin receptors. Using a selective oxytocin receptor ligand [(125)l]d(CH(2))(5)[Tyr(Me)(2),Tyr-NH(2) (9)]ornithine vasotocin ([(125)I]OTA), specific binding was found in several regions including the anterior olfactory nucleus, the ventromedial nucleus of the hypothalamus, the bed nucleus of the stria terminalis, the amygdala and several cortical areas. Following ovariectomy, oestradiol benzoate (10 mug) administration increased oxytocin receptor binding 100% in the anterior olfactory nucleus, but did not affect receptors in other regions. Gonadallyintact females, exposed to male chemosignals, had significant increases in both endogenous oestradiol levels and anterior olfactory nucleus oxytocin receptor binding relative to gonadally-intact females unexposed to male chemosignals. Following prolonged exposure to males with ad libitum mating, [(125)I]OTA receptor binding decreased to the levels found in unstimulated females. These results demonstrate that increases in oestrogen levels, of either exogenous or endogenous origin, can modulate oxytocin receptors in the brains of female prairie voles. In contrast to rats, oestrogen in female prairie voles appears to affect receptors in the anterior olfactory nucleus rather than the hypothalamus. We suggest that the species differences in oxytocin receptor distribution and gonadal steroid responsiveness reflect variations in reproductive physiology and possibly behaviour.
摘要 先前的研究表明，大鼠前脑特定核内的催产素受体受性腺类固醇的调节。本研究采用体外受体放射自显影技术，研究了雌性草原田鼠（Microtus ochrogaster）前脑内催产素受体的分布和调节。与大鼠不同的是，在雌性草原田鼠中，性腺类固醇的分泌和发情行为是由雄性化学信号刺激引起的，排卵是通过交配诱导的。因此，草原田鼠的大脑为研究环境刺激、性腺类固醇和催产素受体之间的联系提供了机会。使用选择性催产素受体配体 [(125)I]d(CH(2))(5)[Tyr(Me)(2),Tyr-NH(2) (9)]鸟氨酸加压素 ([(125)I]OTA)，在前嗅核、下丘脑腹内侧核、终纹床核、杏仁核和几个皮质区发现了特定的结合。卵巢切除术后，苯甲酸雌二醇（10 微克）给药使前嗅核内催产素受体结合增加 100%，但不影响其他区域的受体。暴露于雄性化学信号下的性腺完整的雌性，其内源性雌二醇水平和前嗅核催产素受体结合均显著增加，而未暴露于雄性化学信号下的性腺完整的雌性则没有增加。在与雄性自由交配的长期暴露后，[(125)I]OTA 受体结合降低到未受刺激的雌性中的水平。这些结果表明，无论是外源性还是内源性雌激素水平的增加，都可以调节雌性草原田鼠大脑中的催产素受体。与大鼠不同的是，雌性草原田鼠中的雌激素似乎影响前嗅核中的受体，而不是下丘脑。我们认为，催产素受体分布和性腺类固醇反应性的种间差异反映了生殖生理学和行为的变化。
