Exposure to estrous ewe urine stimulates investigation and mounting activity in sexually active but not sexually inactive rams. It was hypothesized sexual indifference may result from an inability to detect olfactory cues or an interruption of the pathway from detection of the olfactory stimulus to the motor response. Sexually active (n=4) and inactive (n=3) rams were exposed to urine from estrous ewes. An additional group of sexually active rams (n=3) were exposed to urine from ovariectomized ewes. Rams were exsanguinated following 1 h of exposure to stimulus. Neural activity was determined in tissues of interest by the presence of fos and fos-related proteins detected by immunohistochemistry procedures. Sexually active rams exposed to urine from ovariectomized ewes had more (P ≤ 0.05) fos-positive cells in the olfactory bulb, but fewer (P = 0.03) fos-positive cells in the cortical amygdala compared to sexually active rams exposed to urine from estrous ewes. Sexually inactive rams had similar (P ≥ 0.13) numbers of fos positive neurons in the olfactory bulb and medial amygdala but fewer (P ≤ 0.04) in the central amygdala, bed nucleus of the stria terminalis and the medial preoptic area compared to sexually active rams exposed to urine from estrous ewes. Sexual inactivity was not associated with decreased hypothalamic function since fos activity was similar (P ≥ 0.14) among groups in the suprachiasmatic and ventral medial nucleus. Sexual inactivity is not likely due to an impaired ability to detect or process olfactory stimuli by the main olfactory bulb and medial-cortical amygdala. Sexually inactive rams may have reduced attentiveness to sexual stimuli and/or decreased responsiveness of regions in the brain which regulate reproductive behaviors.

中文翻译：

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Fos 在暴露于发情或去卵巢母羊尿液的高性和低性公羊的嗅觉通路中的表达

暴露于发情的母羊尿液会刺激性活跃但不活跃的公羊的调查和增加活动。假设性冷漠可能是由于无法检测嗅觉线索或从检测嗅觉刺激到运动反应的途径中断造成的。性活跃的 (n=4) 和不活跃的 (n=3) 公羊暴露于来自发情母羊的尿液。另一组性活跃的公羊 (n=3) 暴露于来自切除卵巢的母羊的尿液。公羊在暴露于刺激下 1 小时后放血。通过免疫组织化学程序检测到的 fos 和 fos 相关蛋白的存在，确定感兴趣组织中的神经活性。暴露于去卵巢母羊尿液中的性活跃公羊在嗅球中有更多 (P ≤ 0.05) fos 阳性细胞，但较少 (P = 0. 03) 与暴露于发情母羊尿液的性活跃公羊相比，皮质杏仁核中的 fos 阳性细胞。与性活跃的公羊相比，性不活跃的公羊在嗅球和内侧杏仁核中的 fos 阳性神经元数量相似（P ≥ 0.13），但中央杏仁核、终纹床核和内侧视前区的 fos 阳性神经元数量较少（P ≤ 0.04）暴露于发情母羊的尿液。性不活动与下丘脑功能下降无关，因为视交叉上核和腹内侧核各组的 fos 活动相似（P ≥ 0.14）。由于主要嗅球和内侧皮质杏仁核检测或处理嗅觉刺激的能力受损，性行为不活跃不太可能。