Hamson D K, Jones B A, Watson N V
Hormones and Behaviour Laboratory, Department of Psychology, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
Neuroscience. 2004;127(4):797-803. doi: 10.1016/j.neuroscience.2004.06.006.
Gonadal steroids such as testosterone and estrogen are necessary for the normal activation of male rat sexual behavior. The medial preoptic area (MPOA), an important neural substrate regulating mating, accumulates steroids and also expresses functional androgen receptors (AR). The MPOA is intimately connected with other regions implicated in copulation, such as the bed nucleus of the stria terminalis and medial amygdala. Inputs to the MPOA arise from several areas within the brainstem, synapsing preferentially onto steroid sensitive MPOA cells which are activated during sexual activity. Given that little is known about the distribution of AR protein in the brainstem of male rats, we mapped the distribution of AR expressing cells in the pons and medulla using immunocytochemistry. In agreement with previous reports, AR immunoreactivity (AR-ir) was detected in ventral spinal motoneurons and interneurons. In addition, AR-ir was detected in areas corresponding to the solitary tract, lateral paragigantocellular and alpha and ventral divisions of the gigantocellular reticular nuclei, area postrema, raphe pallidus, ambiguus nucleus, and intermediate reticular nucleus. Several regions within the pons contained AR-ir, such as the tegmental and central gray, parabrachial nucleus, locus coeruleus, Barrington's nucleus, periaqueductal gray, and dorsal raphe. In contrast with in situ hybridization studies, auditory and somatosensory areas were AR-ir negative, and, except for very light staining in the prepositus nucleus, areas carrying vestibular information did not display AR-ir. Additionally, cranial nerve motoneurons of the hypoglossal, facial, dorsal vagus, and spinal trigeminal did not display AR-ir in contrast to previous reports. The data presented here indicate that androgens may influence numerous cell groups within the brainstem. Some of these probably constitute a steroid sensitive circuit linking the MPOA to motoneurons in the spinal cord via androgen responsive cells in the caudal ventral medulla.
睾酮和雌激素等性腺类固醇对于正常激活雄性大鼠的性行为是必需的。内侧视前区（MPOA）是调节交配行为的重要神经基质，它会积累类固醇并表达功能性雄激素受体（AR）。MPOA与其他参与交配的区域密切相连，如终纹床核和内侧杏仁核。来自脑干内多个区域的输入投射到MPOA，优先与性活动期间被激活的类固醇敏感的MPOA细胞形成突触联系。鉴于对雄性大鼠脑干中AR蛋白分布了解甚少，我们采用免疫细胞化学方法绘制了脑桥和延髓中表达AR细胞的分布图。与先前的报道一致，在腹侧脊髓运动神经元和中间神经元中检测到了AR免疫反应性（AR-ir）。此外，在与孤束、外侧巨细胞旁核以及巨细胞网状核的α和腹侧亚核、最后区、中缝苍白核、疑核和中间网状核相对应的区域也检测到了AR-ir。脑桥内的几个区域含有AR-ir，如被盖和中央灰质、臂旁核、蓝斑、巴林顿核、导水管周围灰质和背侧中缝核。与原位杂交研究不同，听觉和躯体感觉区域为AR-ir阴性，除了前庭前核有非常淡的染色外，携带前庭信息的区域未显示AR-ir。此外，与先前报道不同，舌下神经、面神经、迷走背核和三叉神经脊髓核的脑神经运动神经元未显示AR-ir。此处呈现的数据表明雄激素可能影响脑干内的众多细胞群。其中一些细胞群可能构成一个类固醇敏感回路，通过尾侧腹侧延髓中的雄激素反应性细胞将MPOA与脊髓中的运动神经元相连。
