Homeostatic Mechanism Research Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan.
Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan.
Cell Rep. 2024 Jan 23;43(1):113619. doi: 10.1016/j.celrep.2023.113619. Epub 2023 Dec 28.
Thirst and salt appetite are temporarily suppressed after water and salt ingestion, respectively, before absorption; however, the underlying neural mechanisms remain unclear. The parabrachial nucleus (PBN) is the relay center of ingestion signals from the digestive organs. We herein identify two distinct neuronal populations expressing cholecystokinin (Cck) mRNA in the lateral PBN that are activated in response to water and salt intake, respectively. The two Cck neurons in the dorsal-lateral compartment of the PBN project to the median preoptic nucleus and ventral part of the bed nucleus of the stria terminalis, respectively. The optogenetic stimulation of respective Cck neurons suppresses thirst or salt appetite under water- or salt-depleted conditions. The combination of optogenetics and in vivo Ca imaging during ingestion reveals that both Cck neurons control GABAergic neurons in their target nuclei. These findings provide the feedback mechanisms for the suppression of thirst and salt appetite after ingestion.
水和盐摄入后，分别在吸收前暂时抑制口渴和盐欲；然而，其潜在的神经机制尚不清楚。臂旁核（PBN）是来自消化器官的摄入信号的中继中心。我们在此鉴定出两个在外侧 PBN 中表达胆囊收缩素（Cck）mRNA 的不同神经元群体，它们分别对水和盐的摄入产生反应而被激活。PBN 背外侧隔室中的两个 Cck 神经元分别投射到正中视前核和终纹床核腹侧部分。各自的 Cck 神经元的光遗传学刺激在水或盐耗竭条件下抑制口渴或盐欲。在摄入期间进行光遗传学和在体 Ca 成像的组合表明，两个 Cck 神经元均控制其靶核中的 GABA 能神经元。这些发现为摄入后口渴和盐欲的抑制提供了反馈机制。
