Steroidal control of male hamster sexual behavior in Me and MPOA: effects of androgen dose and tamoxifen.
Steroidal control of male hamster sexual behavior in Me and MPOA: effects of androgen dose and tamoxifen.
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Me 和 MPOA 中雄性仓鼠性行为的类固醇控制：雄激素剂量和他莫昔芬的影响。
DOI：
10.1016/s0031-9384(01)00427-9
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发表时间：
2001
影响因子：
2.9
通讯作者：
Williams,SJ
中科院分区：
文献类型：
--
作者：
Wood,RI;Williams,SJ
类固醇通过相互连接的边缘核刺激男性性行为，包括内侧杏仁核（Me）和内侧视前区（MPOA）。虽然Me和MPOA都可以抑制激素信号，诱导去势雄性仓鼠的性活动，但同时刺激Me和MPOA不能扩大交配。本研究通过测试（1）增加单个脑区类固醇剂量或（2）用雌激素拮抗剂局部阻断类固醇作用的行为效应，扩展了我们对交配激素控制冗余的研究。在实验1中，有性经验的阉割者在Me中接受单次睾酮植入、双侧睾酮植入或单次植入高效雄激素7 α-甲基-19-去甲睾酮（MENT）。这些处理刺激交配行为：术后2周，在每组≥50%的雄性动物中观察到交配。在实验2中，去势男性接受脑内植入的雌激素拮抗剂他莫昔芬在我或MPOA，结合全身睾酮替代。MPOA中的他莫昔芬对交配行为的恢复影响最小。在Me中使用他莫昔芬，术后18天的坐骑和导入显著减少。然而，每组中表达坐骑，插入或射精的男性百分比没有差异。因此，在实验1中，增加类固醇的量不会扩大交配。同样，实验2中局部阻断激素作用也不能阻止行为。这些发现支持了类固醇在很大程度上允许男性性行为的概念。Me或MPOA的类固醇刺激足以进行性活动。相反，Me和MPOA都不需要绝对的激素来促进交配的表达。
Steroids stimulate male sexual behavior through interconnected limbic nuclei, including the medial amygdala (Me) and medial preoptic area (MPOA). Although Me and MPOA each can transduce hormonal cues to induce sexual activity in castrated male hamsters, simultaneous stimulation of Me and MPOA fails to amplify mating. The present study extends our investigations of redundancy in the hormonal control of mating by testing the behavioral effects of (1) increasing steroid dose in a single brain region or (2) locally blocking steroid action with an estrogen antagonist. In Experiment 1, sexually experienced castrates received a single testosterone implant in Me, bilateral testosterone implants, or a single implant of a highly potent androgen, 7a-methyl-19-nortestosterone (MENT). These treatments stimulated mating behavior: 2 weeks after surgery, mounting was observed in ≥50% of the males in each group. In Experiment 2, castrated males received intracerebral implants of the estrogen antagonist tamoxifen in Me or MPOA, combined with systemic testosterone replacement. Tamoxifen in MPOA had minimal effects on the recovery of mating behavior. With tamoxifen in Me, mounts and intromissions were significantly reduced 18 days after surgery. However, the percent of males in each group that expressed mounts, intromissions or ejaculations was not different. Thus, in Experiment 1, increasing the amount of steroid does not amplify mating. Likewise, local blockade of hormone action in Experiment 2 does not prevent behavior. These findings support the concept that steroids are largely permissive for male sex behavior. Steroid stimulation of either Me or MPOA is sufficient for sexual activity. Conversely, neither Me nor MPOA has an absolute requirement for hormones to facilitate expression of mating.