Swann J M, Macchione N
Department of Biological Sciences, Rutgers State University, Newark, NJ 07102.
Brain Res. 1992 Sep 11;590(1-2):29-38. doi: 10.1016/0006-8993(92)91078-s.
Mating behavior in the male golden hamster is regulated by both gonadal steroids and photoperiod. Gonadal steroids may regulate mating behavior by actions on the medial nucleus of the amygdala, bed nucleus of the stria terminalis, and medial preoptic area. Neurons in these areas actively accumulate gonadal steroids and lesions of these nuclei disrupt mating behavior in male hamsters. Photoperiodic regulation of mating behavior is regulated, at least in part, by decreased responsiveness to gonadal steroids. Therefore, we sought to determine if the changes induced by changes in gonadal steroids would mimic those induced by changes in photoperiod. The number of substance P-containing neurons in these areas decrease following castration and are restored with testosterone treatment suggesting that this peptide may mediate steroidal regulation of male mating behavior. To determine the effect of photoperiod on substance P, peptide containing neurons were counted in (1) enucleates (n = 6), (2) enucleated castrates treated with testosterone (n = 6), (3) castrates treated with testosterone (n = 4), and (4) intact controls (n = 6). Bilateral enucleation caused a decrease in the number of substance P neurons in the medial nucleus, bed nucleus of the stria terminalis, and medial preoptic area (P less than 0.05). Testosterone treatment prevented this decrease (P less than 0.05). Thus, a decrease in daylength causes a decrease in substance P in the medial nucleus of the amygdala, the medial bed nucleus of the stria terminalis and the medial preoptic area that is mediated by changes in testosterone levels.
雄性金黄地鼠的交配行为受性腺类固醇和光周期的双重调节。性腺类固醇可能通过作用于杏仁核内侧核、终纹床核和视前内侧区来调节交配行为。这些区域的神经元会主动积累性腺类固醇，而这些核团的损伤会破坏雄性仓鼠的交配行为。交配行为的光周期调节至少部分是由对性腺类固醇反应性降低所介导的。因此，我们试图确定性腺类固醇变化所诱导的改变是否会模拟光周期变化所诱导的改变。阉割后，这些区域中含P物质的神经元数量减少，而睾酮治疗可使其恢复，这表明该肽可能介导雄性交配行为的类固醇调节。为了确定光周期对P物质的影响，对以下几组动物中含肽神经元进行计数：(1) 摘除眼球的动物（n = 6）；(2) 摘除眼球的阉割动物并接受睾酮治疗（n = 6）；(3) 接受睾酮治疗的阉割动物（n = 4）；以及(4) 完整对照组（n = 6）。双侧摘除眼球导致杏仁核内侧核、终纹床核和视前内侧区中P物质神经元数量减少（P < 0.05）。睾酮治疗可防止这种减少（P < 0.05）。因此，白昼长度的缩短会导致杏仁核内侧核、终纹床核内侧和视前内侧区中P物质减少，这是由睾酮水平的变化所介导的。
