Sexually Dimorphic Risk Mitigation Strategies in Rats.
Sexually Dimorphic Risk Mitigation Strategies in Rats.
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DOI：
10.1523/eneuro.0288-16.2017
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发表时间：
2017-01
期刊：
影响因子：
3.4
通讯作者：
Kim JJ
中科院分区：
文献类型：
--
作者：
Pellman BA;Schuessler BP;Tellakat M;Kim JJ
对恐惧和焦虑的科学理解--无论是正常形式的还是病理形式的--目前都受到主要研究的限制，这些研究使用雄性动物和巴甫洛夫式的以恐惧为中心的范式，在短暂的采样期内限制和评估特定的行为(例如，冻结)，而忽视了时空背景对动物对威胁的行为反应的更广泛的贡献。在这里，我们使用一个高风险的“封闭经济”系统，在这个系统中，获取食物和水的需要以及避免威胁的需要同时融入老鼠的生活中，以考察在觅食时降低威胁风险方面的性别差异。大鼠在由一个安全的床窝和一个危险的觅食区域组成的大房间里生活了很长一段时间(∼2个月)，在那里，脚电可能会不可预测地传递。我们观察到，雄性和雌性大鼠使用不同的策略来应对足部电击的威胁。雄性大鼠为了减少觅食所花费的总时间而增加了进食量，而雌性大鼠为了避免休克而牺牲了自己的新陈代谢需求。卵巢激素的波动被证明对性腺完整的雌性大鼠的危险决策产生轻微但可靠的节律性影响。然而，这并没有在卵巢切除组和完整雌性组之间的接近-避免权衡上产生显著的差异，这表明男性和女性的性别差异不是由于性腺激素的激活效应，而是很可能在早期发育期间组织起来的。
The scientific understanding of fear and anxiety—in both normal and pathological forms—is presently limited by a predominance of studies that use male animals and Pavlovian fear conditioning-centered paradigms that restrict and assess specific behaviors (e.g., freezing) over brief sampling periods and overlook the broader contributions of the spatiotemporal context to an animal’s behavioral responses to threats. Here, we use a risky “closed economy” system, in which the need to acquire food and water and the need to avoid threats are simultaneously integrated into the lives of rats, to examine sex differences in mitigating threat risk while foraging. Rats lived for an extended period (∼2 months) in enlarged chambers that consisted of a safe, bedded nest and a risky foraging area where footshocks could be delivered unpredictably. We observed that male and female rats used different strategies for responding to the threat of footshock. Whereas male rats increased the size of meals consumed to reduce the overall time spent foraging, female rats sacrificed their metabolic needs in order to avoid shocks. Ovarian hormone fluctuations were shown to exert slight but reliable rhythmic effects on risky decision-making in gonadally intact female rats. However, this did not produce significant differences in approach–avoidance trade-offs between ovariectomized and intact female groups, suggesting that male–female sex differences are not due to the activational effects of gonadal hormones but, rather, are likely to be organized during early development.