Reppucci C J, Gergely C K, Veenema A H
Department of Psychology & Neuroscience Program, Michigan State University, East Lansing, MI 48824, United States.
Department of Psychology, Boston College, Chestnut Hill, MA, 02467, United States.
J Neuroendocrinol. 2018 Feb 9. doi: 10.1111/jne.12582.
Social play is a highly rewarding and motivated behavior predominately displayed by juveniles and expressed by nearly all mammalian species. Prior work suggested that the vasopressin (AVP) and oxytocin (OT) systems can regulate the expression of social play in sex-specific ways. Here we investigated whether there are sex differences in the recruitment of vasopressinergic and oxytocinergic brain regions following social play exposure in juvenile rats. Single-housed rats were allowed to play, in their home cage, with an age- and sex-matched unfamiliar conspecific for 10 min, or received similar handling but no partner. Double-labeled fluorescent immunohistochemistry for Fos and either AVP or OT was completed in adjacent series of tissue to determine recruitment of AVP- and OT-immunoreactive neurons in response to social play. Exposure to social play did not increase recruitment of AVP or OT neurons in the supraoptic (SO) or paraventricular (PVH) hypothalamic nuclei of either sex compared to the no-play control condition. Interestingly, there was a robust sex difference in SO recruitment, irrespective of social play condition, with males exhibiting twice the recruitment of SO-AVP and SO-OT neurons compared to females. Lastly, exposure to social play increased recruitment of the posterior bed nuclei of the stria terminalis (pBST) and the posterodorsal medial amygdalar nucleus (MEApd) compared to the no-play control condition, and this effect was most pronounced in females. Our findings revealed sex differences in the recruitment of brain regions (i) independent of play condition (i.e., SO) possibly representing a sex difference in the baseline levels of AVP and OT signaling required for typical functioning and (ii) specific to play condition (i.e., pBST, MEApd). In sum, this study provides further evidence that the neural substrates underlying social play behavior are sex-specific. This article is protected by copyright. All rights reserved.
社交玩耍是一种极具回报性且有动机驱使的行为，主要由幼体表现出来，几乎所有哺乳动物物种都会展现。先前的研究表明，血管加压素（AVP）和催产素（OT）系统能够以性别特异性的方式调节社交玩耍的表现。在此，我们研究了在幼年大鼠经历社交玩耍后，血管加压素能和催产素能脑区的激活是否存在性别差异。将单笼饲养的大鼠置于其笼舍中，与年龄和性别匹配的陌生同种个体玩耍10分钟，或者接受类似的处理但无同伴。在相邻的组织切片系列中完成Fos与AVP或OT的双标荧光免疫组织化学，以确定响应社交玩耍时AVP和OT免疫反应性神经元的激活情况。与无玩耍的对照条件相比，社交玩耍暴露并未增加任何性别的视上核（SO）或室旁核（PVH）中AVP或OT神经元的激活。有趣的是，无论社交玩耍条件如何，SO激活存在显著的性别差异，与雌性相比，雄性的SO - AVP和SO - OT神经元激活数量是雌性的两倍。最后，与无玩耍的对照条件相比，社交玩耍暴露增加了终纹床核后部（pBST）和杏仁核后内侧背核（MEApd）的激活，且这种效应在雌性中最为明显。我们的研究结果揭示了脑区激活的性别差异：（i）与玩耍条件无关（即SO），这可能代表了典型功能所需的AVP和OT信号基线水平的性别差异；（ii）特定于玩耍条件（即pBST、MEApd）。总之，本研究进一步证明社交玩耍行为的神经基础具有性别特异性。本文受版权保护。保留所有权利。
