Examination of the hyposesis of thermoredulatory module in the hypothalamus.

下丘脑温度调节模块假设的检查。

基本信息

批准号：
09470016
负责人：
KANOSUE Kazuyuki
金额：
$ 8.26万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09470016/
关键词：
Hypothalamus Thermoregulation Autonomous distributing system Nonshivering thermogenesis Shivering Skin vasomotion

项目摘要

Thermosensitive neurons in the hypothalamus, especially in the preoptic area (PO), play important roles in thermoregulation (Boulant, 1980; Simon et al., 1986), but many hypotheses about signal processing in the hypothalamus have remained untested because we don't have precise enough information about the neuronal "network" there. Although it had long been almost an article of faith that warm-sensitive neurons send efferent signals driving heat loss and cold-sensitive neurons send efferent signals driving heat production, we found that warm-sensitive neurons work for the control of heat production as well as heat loss (Zhang et al., 1995). But we have obtained evidence that the PO is simply an assembly of neuronal groups, each sending its own efferent signals to each effector, and that these groups function without connections to each other (Kanosue et al., 1997). In the present study, based upon these findings, we further analyzed the neural network for thermoregulation in the hypothalamus and the midbrain. First, we analyzed the nertwork for nonshivering thermogenesis. Electrical stimulation of the ventromedial hypothalamus elicited thermogenesis of the brown adipose tissure. But the same stimulus had no effect during warming the preoptic area, which means that the PO send inhibitory signals to the VMH. Second, the role of the posterior hypothalmus was investigated by injecting inhibitory substance muscimol. Muscimol injection suppressed cold-induced shivering, which indicates that the excitatory neuron for shivering locates in the posterior hypothalamus. Third, DLH was injected into the ventropoterior region of the PAG and it facilitated nonshivering thermogenesis. The retrograde tracer CTB injection into the medullary raphe labeled neurons in the PAG where nonshivering thermogenesis was facilitated. The excitatory signal seems to decsend from the PAG to the raphe.

下丘脑中的热敏神经元，尤其是视前区 (PO)，在体温调节中发挥着重要作用（Boulant，1980；Simon 等，1986），但许多关于下丘脑信号处理的假设尚未得到检验，因为我们不知道拥有关于那里的神经元“网络”的足够精确的信息。尽管人们长期以来几乎相信热敏感神经元会发送传出信号来驱动热量损失，而冷敏感神经元会发送传出信号来驱动热量产生，但我们发现热敏感神经元不仅可以控制热量产生，还可以控制热量产生。热损失（Zhang 等人，1995）。但我们已经获得证据表明，PO 只是神经元群的集合，每个神经元群向每个效应器发送自己的传出信号，并且这些群的功能彼此之间没有联系（Kanosue 等，1997）。在本研究中，基于这些发现，我们进一步分析了下丘脑和中脑温度调节的神经网络。首先，我们分析了非颤抖产热的神经网络。电刺激下丘脑腹内侧引起棕色脂肪组织的生热作用。但同样的刺激在视前区变暖期间没有效果，这意味着 PO 向 VMH 发送抑制信号。其次，通过注射抑制物质蝇蕈醇来研究下丘脑后部的作用。注射蝇蕈醇可抑制寒冷引起的颤抖，这表明颤抖的兴奋神经元位于下丘脑后部。第三，DLH 被注射到 PAG 的腹后部区域，它促进了非颤抖性产热。将逆行示踪剂 CTB 注射到 PAG 中的髓缝标记神经元中，促进非颤抖产热。兴奋信号似乎从 PAG 下降到中缝。