Department of Psychology, University of New Orleans, New Orleans, LA, United States; Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, United States.
Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, United States.
Horm Behav. 2018 Feb;98:145-158. doi: 10.1016/j.yhbeh.2017.12.007. Epub 2018 Jan 4.
Oxytocin is a social and reproductive hormone that also plays critical roles in a range of homeostatic processes, including thermoregulation. Here, we examine the role of oxytocin (OT) as a mediator of brown adipose tissue (BAT) thermogenesis, cold-induced huddling, and thermotaxis in eight-day-old (PD8) OT 'knock out' (OTKO) mouse pups. We tested OTKO and wildtype (WT) pups in single- and mixed-genotype groups of six, exposing these to a period of ambient warmth (35°C) followed by a period of cold (21.5°C). Whether huddling exclusively with other OTKO or alongside WT pups, OTKO pups showed reduced BAT thermogenesis and were significantly cooler when cold-challenged. Huddles of OTKO pups were also significantly less cohesive than WT huddles during cooling, suggesting that thermoregulatory deficits contribute to contact abnormalities in OTKO pups. To further explore this issue, we examined thermotaxis in individuals and groups of four OTKO or WT pups placed on the cool end of a thermocline and permitted to freely locomote for 2h. When tested individually, male OTKO pups displayed abnormal thermotaxis, taking significantly longer to move up the thermocline and settling upon significantly lower temperatures than WT pups during the 2h test. OTKO mouse pups thus appear to have deficits in both thermogenesis and thermotaxis-the latter deficit being specific to males. Our results add to a growing body of work indicating that OT plays critical roles in thermoregulation and also highlight the entanglement of social and thermoregulatory processes in small mammals such as mice.
催产素是一种社交和生殖激素，在一系列稳态过程中也起着关键作用，包括体温调节。在这里，我们研究了催产素 (OT) 作为棕色脂肪组织 (BAT) 产热、冷诱导蜷缩和趋温的介质的作用，在 8 天大的 (PD8) OT“敲除” (OTKO) 小鼠幼崽中进行了测试。我们在单基因型和混合基因型的六只幼崽中测试了 OTKO 和野生型 (WT) 幼崽，将它们暴露在一段时间的环境温暖 (35°C) 后，再暴露在一段时间的寒冷 (21.5°C) 中。无论是否只与其他 OTKO 幼崽蜷缩在一起，还是与 WT 幼崽一起蜷缩在一起，OTKO 幼崽的 BAT 产热都减少了，在受到冷刺激时明显更冷。在冷却过程中，OTKO 幼崽的蜷缩也明显不如 WT 幼崽紧密，这表明体温调节缺陷导致 OTKO 幼崽的接触异常。为了进一步探讨这个问题，我们在个体和四个 OTKO 或 WT 幼崽的群体中检查了趋温性，这些幼崽被放在温度梯度的冷端，并允许它们自由移动 2 小时。在单独测试时，雄性 OTKO 幼崽表现出异常的趋温性，在 2 小时的测试中，它们向上移动温度梯度的时间明显更长，并且在温度明显较低的情况下定居下来，比 WT 幼崽的时间明显更长。OTKO 小鼠幼崽似乎在产热和趋温方面都存在缺陷，后者的缺陷仅存在于雄性幼崽中。我们的研究结果增加了越来越多的工作表明，OT 在体温调节中起着关键作用，也突出了社交和体温调节过程在小型哺乳动物（如老鼠）中的交织。
