Wood R I, Newman S W
Department of Anatomy and Cell Biology, University of Michigan, Ann Arbor 48109-0616, USA.
J Neurosci. 1995 Nov;15(11):7261-9. doi: 10.1523/JNEUROSCI.15-11-07261.1995.
Mating behavior in the male hamster is dependent upon both chemosensory and hormonal cues, and copulation is abolished if either signal is interrupted. Through reciprocal interactions of these signals, chemosensory stimuli increase circulating testosterone in the male, and the male's hormonal status influences his attraction to female pheromones. Furthermore, anatomical data suggest that these signals are transmitted through parallel pathways in separate subdivisions of the medial amygdaloid nucleus, bed nucleus of the stria terminalis (BNST) and medial preoptic area (MPOA). The aim of this study was to determine if the integration of chemosensory and hormonal cues is essential for mating. We combined an intracerebral implant of testosterone in BNST/MPOA with removal of a single olfactory bulb (UBx), ipsilateral or contralateral to the steroid implant. Previous studies have demonstrated that testosterone implants which stimulate androgen receptor-containing neurons in posteromedial BNST and MPOA can increase mounting in males castrated for 12 weeks. Moreover, unilateral bulbectomy alone does not prevent mating. In the present study, ipsilateral UBx prevents communication between hormonal and chemosensory circuits. Sexually experienced males were used. Twelve weeks after castration, a single olfactory bulb was removed, and each male received a testosterone-filled cannula (23 ga) directed at the MPOA. Two weeks later, sexual activity increased in six males with implants in BNST/MPOA and contralateral UBx, but copulation was not restored in eight males with ipsilateral UBx despite equivalent implant placement. This study demonstrates that communication between neurons receiving hormonal signals and chemosensory cues is required for mating behavior.
雄性仓鼠的交配行为依赖于化学感应和激素信号，若其中任何一种信号被阻断，交配行为就会消失。通过这些信号的相互作用，化学感应刺激会增加雄性仓鼠体内循环的睾酮水平，而雄性的激素状态会影响其对雌性信息素的吸引力。此外，解剖学数据表明，这些信号通过内侧杏仁核、终纹床核（BNST）和内侧视前区（MPOA）不同亚区的平行通路进行传递。本研究的目的是确定化学感应和激素信号的整合对于交配是否至关重要。我们将睾酮脑内植入BNST/MPOA与切除单侧嗅球（UBx）相结合，嗅球切除部位与类固醇植入部位同侧或对侧。先前的研究表明，刺激BNST后内侧和MPOA中含雄激素受体神经元的睾酮植入物可增加阉割12周雄性仓鼠的爬跨行为。此外，单独进行单侧嗅球切除并不妨碍交配。在本研究中，同侧UBx会阻断激素和化学感应回路之间的通讯。使用的是有性经验的雄性仓鼠。阉割12周后，切除单侧嗅球，每只雄性仓鼠接受一根指向MPOA的充满睾酮的套管（23号）。两周后，BNST/MPOA植入且对侧UBx的6只雄性仓鼠的性活动增加，但同侧UBx的8只雄性仓鼠尽管植入位置相同，交配行为却未恢复。本研究表明，接受激素信号和化学感应信号的神经元之间的通讯是交配行为所必需的。
