Oral gavage of capsaicin causes TRPV1-dependent acute hypothermia and TRPV1-independent long-lasting increase of locomotor activity in the mouse
Oral gavage of capsaicin causes TRPV1-dependent acute hypothermia and TRPV1-independent long-lasting increase of locomotor activity in the mouse
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DOI：
10.1016/j.physbeh.2019.04.015
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发表时间：
2019-07-01
影响因子：
2.9
通讯作者：
Miyata, S.
中科院分区：
文献类型：
--
作者：
Inagaki, H.;Kurganov, E.;Miyata, S.
辣椒素（Capsaicin，CAP）是辣椒中的辛辣成分，是热敏瞬时受体电位V1阳离子通道1（TRPV 1）的选择性配体。虽然CAP在世界上已被传统地用作各种食品的香料成分，但口服CAP对体温调节和运动活动的影响以及CAP诱导的脑神经回路激活尚不清楚。因此，在这项研究中，我们研究了口服灌胃CAP对核心体和尾表面温度，自发活动，Fos表达的温度调节和感觉信息相关的下丘脑和延髓脑区使用自由移动的小鼠。经口灌胃CAP可使野生型（WT）小鼠的核心体温急剧下降，并可选择性地使尾表面温度升高，而在TRPV1敲除（KO）动物中未观察到这种急性温度变化。此外，经口灌胃CAP后，在WT和TRPV1 KO小鼠中均观察到运动活动的长期持续增加，但仅在TRPV1 KO动物中观察到核心体温升高。经口灌胃CAP可诱导脑室周围器官、正中和内侧视前区、弓状核和孤束核的神经元Fos表达，而TRPV 1 KO小鼠几乎未观察到神经元Fos表达。因此，本研究表明，在小鼠中，CAP的口服摄入导致TRPV1依赖性的急性体温降低和TRPV1非依赖性的运动活动的持久增加，并且还激活了控制体温调节和代谢的脑回路。
Capsaicin (CAP), the pungent ingredient of hot red pepper, is a selective ligand for the heat-sensitive transient receptor potential V1 cation channel 1 (TRPV1). Although CAP has been traditionally used as the ingredient of spices for various foods in the world, the effect of oral intake of CAP on thermoregulation and locomotor activity, and CAP-induced activation of brain neural circuits are not well understood. In this study, therefore, we examined the effects of oral gavage of CAP on core body and tail surface temperature, locomotor activity, and Fos expression in thermoregulation- and sensory information-associated hypothalamic and medullary brain regions using freely moving mice. Oral gavage of CAP acutely decreased core body temperature and alternatively increased tail surface temperature of wild type (WT) mice, whereas such acute temperature changes were not observed in TRPV1 knockout (KO) animals Moreover, a long-lasting increase of locomotor activity was observed in both WT and TRPV1 KO mice after oral gavage of CAP, but increage in core body temperature was seen only in TRPV1 KO animals. Oral gavage of CAP induced neuronal Fos expression in the circumventricular organs, median and medial preoptic area, arcuate nucleus, and nucleus of the solitary tract, whereas neuronal Fos expression was scarcely observed in TRPV1 KO mice. Thus, the present study demonstrates in the mice that oral intake of CAP causes TRPV1-dependent acute hypothermia and TRPV1-independent long-lasting increase of locomotor activity, and moreover activates the brain circuits controlling thennoregulation and metabolism.