Department of Neurology, China Medical University Hospital No. 1, Shenyang 110001, China.
Behav Brain Res. 2013 May 15;245:42-9. doi: 10.1016/j.bbr.2013.02.002. Epub 2013 Feb 10.
The medial amygdala and neuropeptides oxytocin (OXT) and vasopressin (VSP) have been associated aggressive behavior regulation. However, the specific mechanism involved in OXT and VSP modulation in distinct brain regions during hostile intermale aggressive behavior is undetermined. A retrograde tracer mouse model was employed using male C57BL/6 mice injected with rhodamine-conjugated latex microsphere suspensions in the right hypothalamic paraventricular nucleus. Adult male C57BL/6 mice (aged 14-16 weeks) were subjected to resident-intruder testing using juvenile intruder mice (aged 3 weeks) or adult intruder mice (aged 8 weeks). Following exposure, Fos protein expression was increased in the medial amygdala neurons of resident mice receiving the retrograde tracer. Thus, medial amygdala neurons projecting to or localized in the vicinity of the hypothalamic paraventricular nucleus showed immediate early gene (IEG) expression following resident-intruder testing that was considered an indirect marker of activation. Additionally, intermale aggression-related behaviors were inhibited or modified by exposure to juvenile or adult intruders, respectively, in mice that underwent medial amygdala lesioning. Furthermore, Fos protein expression in OXT-positive neurons was attenuated. Thus, ablation of medial amygdala neurons prevented immediate early gene expression in OXT- and VSP-positive neurons in the hypothalamus, bed nucleus of stria terminalis, and medial preoptic area during intermale exposure. These findings indicate that the medial amygdala likely modulates hostile aggressive behavior associated with immediate early gene expression in OXT and VSP neurons in specific brain areas, which may actually be instrumental in beneficial social interaction-related aggressive responses associated with mating, territorial defense, and offspring protection.
内侧杏仁核和神经肽催产素 (OXT) 和加压素 (VSP) 与攻击性调节有关。然而，在雄性间敌对攻击行为中，OXT 和 VSP 在不同脑区的调节中涉及的具体机制尚不清楚。使用雄性 C57BL/6 小鼠，通过将罗丹明缀合的乳胶微球混悬液注射到右侧下丘脑室旁核，建立逆行示踪小鼠模型。成年雄性 C57BL/6 小鼠（14-16 周龄）通过幼鼠入侵者（3 周龄）或成年入侵者（8 周龄）进行居留者-入侵者测试。暴露后，接受逆行示踪剂的居留者小鼠的内侧杏仁核神经元中 Fos 蛋白表达增加。因此，在居留者-入侵者测试后，投射到下丘脑室旁核或位于其附近的内侧杏仁核神经元显示出即时早期基因（IEG）表达，这被认为是激活的间接标志物。此外，在接受内侧杏仁核损伤的小鼠中，分别暴露于幼鼠或成年入侵者会抑制或改变雄性间攻击相关行为。此外，OXT 阳性神经元中的 Fos 蛋白表达减弱。因此，内侧杏仁核神经元的消融阻止了雄性间暴露期间下丘脑、终纹床核和内侧视前区 OXT 和 VSP 阳性神经元中的即时早期基因表达。这些发现表明，内侧杏仁核可能通过调节与特定脑区 OXT 和 VSP 神经元中的即时早期基因表达相关的敌对攻击行为，这可能实际上有助于与交配、领地防御和后代保护相关的有益社交互动相关的攻击反应。
