Minami Saki, Nomura Hiroshi, Minami Masabumi
Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Neuropsychopharmacol Rep. 2018 Dec;38(4):214-218. doi: 10.1002/npr2.12036. Epub 2018 Oct 19.
Thermoregulatory responses in homeothermic animals, including humans, are classified into involuntary autonomous and voluntary behavioral thermoregulatory responses. Although behavioral thermoregulatory responses are probably driven by positive (pleasant) and/or negative (unpleasant) emotions, the neuronal mechanisms underlying the induction of negative emotions by hot and cold environments remain poorly understood. The bed nucleus of the stria terminalis is a brain region implicated in stress responses and negative emotions, such as fear, anxiety, and aversion. Various stimuli that cause negative emotions, such as immobilization stress, fox odor, gastric distension, and inflammatory pain, increase noradrenaline release in the rat bed nucleus of the stria terminalis, especially in the ventral bed nucleus of the stria terminalis. It has been reported that the negative emotional component of pain is mediated by noradrenergic neurotransmission in the ventral bed nucleus of the stria terminalis. However, the role of intra-ventral bed nucleus of the stria terminalis noradrenergic neurotransmission in the induction of negative emotion by exposure to hot and cold environments remains to be elucidated. For the first step to address this issue, the effects of hot and cold environments on noradrenaline release in the ventral bed nucleus of the stria terminalis were examined.
In vivo microdialysis analyses in unanesthetized, freely moving male Sprague-Dawley rats were performed to examine hot and cold environments-induced noradrenaline release in the ventral bed nucleus of the stria terminalis.
Exposure to hot (38°C) and cold (8°C) environments significantly increased noradrenaline release in the ventral bed nucleus of the stria terminalis.
The results suggest that exposure to hot and cold environments enhances noradrenergic neurotransmission in the ventral bed nucleus of the stria terminalis, which may induce negative emotion, and thereby drive avoidance behaviors, that is, escape from hot and cold environments.
恒温动物（包括人类）的体温调节反应分为非自主的自主体温调节反应和自主的行为体温调节反应。尽管行为体温调节反应可能由积极（愉悦）和/或消极（不愉快）情绪驱动，但热环境和冷环境诱发消极情绪的神经机制仍知之甚少。终纹床核是一个与应激反应和消极情绪（如恐惧、焦虑和厌恶）有关的脑区。各种导致消极情绪的刺激，如固定应激、狐狸气味、胃扩张和炎性疼痛，都会增加大鼠终纹床核，特别是终纹床核腹侧的去甲肾上腺素释放。据报道，疼痛的消极情绪成分由终纹床核腹侧的去甲肾上腺素能神经传递介导。然而，终纹床核腹侧去甲肾上腺素能神经传递在热环境和冷环境暴露诱发消极情绪中的作用仍有待阐明。为了解决这个问题的第一步，研究了热环境和冷环境对终纹床核腹侧去甲肾上腺素释放的影响。
对未麻醉、自由活动的雄性Sprague-Dawley大鼠进行体内微透析分析，以检测热环境和冷环境诱发的终纹床核腹侧去甲肾上腺素释放。
暴露于热环境（38°C）和冷环境（8°C）显著增加了终纹床核腹侧的去甲肾上腺素释放。
结果表明，暴露于热环境和冷环境会增强终纹床核腹侧的去甲肾上腺素能神经传递，这可能诱发消极情绪，从而驱动回避行为，即逃离热环境和冷环境。
