Acid-base balance in brain extracellular fluid (EDF) and control of breathing

脑细胞外液 (EDF) 中的酸碱平衡和呼吸控制

基本信息

批准号：
61570364
负责人：
ARITA Hideho
金额：
$ 1.6万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

The present project has revealed the following new findings on dynamic properties and locations of the central chemoreceptors.1. In order to stimulate repeatedly the central chemoreceptors, we developed a technique of vertebral arterial injections of CO2-saturated saline in decerebrated, spontaneously breathing cats. The injections evoked an initial transient inhibition of ongoing respiratory activity, followed by the subsequent excitation: the initial inhibition was due to activation of vascular nociceptors and the subsequent excitation due to stimulation of the central chemoreceptors (J. Appl. Physiol.).2. Applying this technique, we studied the changes in activity of medullary neurons (146 units) with non-phasic discharges. Eighteen units were found to be excited exclusively by stimulation of the central chemoreceptors (namely, possible candidates for pH-sensitive neurons), and they were distributed mainly in the vicinity of ventral respiratory group (VRG) neurons as well as in the … More dorsal area ventral to the solitary tract (ST), though less in number (Brain Res. 1988).3. Using liquid membrane pH microelectrodes, we found intramedullary regions in which ECF pH shifted to the acid side in the same time course as respiratory excitation when CO2 in the vertebral artery was raised in stepwise fashion. These areas were found to overlap with the regions of "possible candidates for pH-sensitive neurons"4. The regions described above were revealed to be supplied by the following vessels (by means of Technovit); the anterior inferior cerebellar artery, the Posterior inferior cerebellar artery and an unnamed artery arising from the basilar artery.Based upon the foregoing evidence, we have hypothesized that the central chemoreceptors would consist of pH-sensitive neurons and the surrounding structures (capillaries and glial cells) which regulate ECF pH, and that they are located in the vicinity of the VRG and in the dorsal area ventral to the ST, which were perfused by the vertebral basilar arterial system. Less

本项目揭示了以下关于中枢化学感受器的动态特性和位置的新发现。1.为了反复刺激中枢化学感受器，我们开发了一种向去大脑、自主呼吸的猫的椎动脉注射二氧化碳饱和盐水的技术。注射引起了持续呼吸活动的最初短暂抑制，随后是随后的兴奋：最初的抑制是由于血管伤害感受器的激活，随后的兴奋是由于刺激中枢所致。化学感受器（J. Appl. Physiol.）2。应用这种技术，我们研究了非阶段性放电的髓质神经元（146 个单位）的活动变化，发现 18 个单位仅通过刺激中枢化学感受器而被兴奋。即，pH 敏感神经元的可能候选者），它们主要分布在腹侧呼吸群 (VRG) 神经元附近以及孤立神经元腹侧的背侧区域道（ST），尽管数量较少（Brain Res. 1988）。3.使用液膜pH微电极，我们发现当CO2进入椎骨时，ECF pH在与呼吸兴奋相同的时间过程中向酸性侧移动。发现这些区域与“pH敏感神经元的可能候选区域”4重叠，上述区域由以下血管提供。小脑前下动脉、小脑后下动脉和源自基底动脉和神经胶质细胞的未命名动脉）调节 ECF pH，它们位于 VRG 附近和 ST 腹侧的背侧区域。，它们被灌注了椎基底动脉系统较少。