Department of Structural and Functional Biology, Institute of Biosciences, Sao Paulo State University-UNESP, Botucatu, SP, Brazil.
Department of Animal Morphology and Physiology, Sao Paulo State University-FCAV, Jaboticabal, SP, Brazil.
Exp Physiol. 2022 Nov;107(11):1298-1311. doi: 10.1113/EP090318. Epub 2022 Aug 22.
What is the central question of this study? Melanin-concentrating hormone (MCH) suppresses the hypercapnic chemoreflex: what is the mechanism by which this effect is produced? What is the main finding and its importance? MCH acting in the lateral hypothalamic area but not in the locus coeruleus in rats, in the light period, attenuates the hypercapnic chemoreflex. The data provide new insight into the role of MCH in the modulation of the hypercapnic ventilatory response.
Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide involved in a broad range of homeostatic functions including regulation of the hypercapnic chemoreflex. We evaluated whether MCH modulates the hypercapnic ventilatory response by acting in the lateral hypothalamic area (LHA) and/or in the locus coeruleus (LC). Here, we measured pulmonary ventilation ( ), body temperature, electroencephalogram (EEG) and electromyogram (EMG) of unanaesthetized adult male Wistar rats before and after microinjection of MCH (0.4 mM) or MCH receptor 1 (MCH1-R) antagonist (SNAP-94847; 63 mM) into the LHA and LC, in room air and 7% CO conditions during wakefulness and sleep in the dark and light periods. MCH intra-LHA caused a decreased CO ventilatory response during wakefulness and sleep in the light period, while SNAP-94847 intra-LHA increased this response, during wakefulness in the light period. In the LC, MCH or the MCH1-R antagonist caused no change in the hypercapnic ventilatory response. Our results suggest that MCH, in the LHA, exerts an inhibitory modulation of the hypercapnic ventilatory response during the light-inactive period in rats.
本研究的核心问题是什么？
黑色素浓缩激素（MCH）抑制高碳酸血症化学感受器反射：产生这种效应的机制是什么？
主要发现及其重要性是什么？
在大鼠的外侧下丘脑区域（LHA）而不是蓝斑核中，MCH 在光周期中作用于大鼠，减弱了高碳酸血症化学感受器反射。
数据提供了关于 MCH 在调节高碳酸血症通气反应中的作用的新见解。
黑色素浓缩激素（MCH）是一种下丘脑神经肽，参与广泛的稳态功能，包括调节高碳酸血症化学感受器反射。
我们评估了 MCH 是否通过在外侧下丘脑区域（LHA）和/或蓝斑核（LC）中作用来调节高碳酸血症通气反应。
在这里，我们在麻醉前测量了未麻醉成年雄性 Wistar 大鼠的肺通气量（VE）、体温、脑电图（EEG）和肌电图（EMG），然后在微注射 MCH（0.4 mM）或 MCH 受体 1（MCH1-R）拮抗剂（SNAP-94847；63 mM）进入 LHA 和 LC 后，在清醒和睡眠期间，在房间空气中和 7% CO 条件下，在黑暗和光周期中。
MCH 进入 LHA 导致清醒和光周期睡眠期间的 CO 通气反应降低，而 SNAP-94847 进入 LHA 则增加了光周期中清醒时的这一反应。
在 LC 中，MCH 或 MCH1-R 拮抗剂对高碳酸血症通气反应没有影响。
我们的结果表明，MCH 在 LHA 中对大鼠光不活跃期的高碳酸血症通气反应产生抑制性调节。
