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Molecular mechanism and ultrastructure of the arterial chemoreceptor organ in chronically hypoxia

慢性缺氧时动脉化学感受器的分子机制及超微结构

基本信息

批准号：
05670024
负责人：
KUSAKABE Tatsumi
金额：
$ 0.9万
依托单位：
Yokohama City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05670024/
关键词：
Hypoxia Carotid body Ultrastructure 3-D architecture Neuropeptides Immunohistochemistry Second messenger Trachea

项目摘要

The carotid bodies, which are the primary organs for sensing O_2 tension in arterial blood, are enlarged in rat exposed to chronic hypoxia (380 torr, 12 weeks). We noted some ultrastructural features with chronic hypoxia which are characteristic of the amphibian carotid labyrinth glomus cells : 1) incomplete covering of glomus cells with the supporting cell missing over a wide area, 2) long thin cytoplasmic projections in the intervascular stroma, and 3) intimate apposition of the glomus cells and endothelial cells, pericytes, and others. Threedimensional analysis using a combination of an ultra high voltage electron microscope (400kV) and semi-thin sections clearly demonstrated that the incomplete covering of glomus cells is based on a difference in an extent of hypertrophy between glomus cells and supporting cells. Because arterial PO_2 is generally low in amphibia, these ultrastructural similarities may be general features of hypoxic adaptation and facilitate both uptake of oxygen from blood and release of catecholamine into the blood.When the distribution and abundance of the peptidergic fibers were compared between normoxic and chronically hypoxic carotid bodies and tracheas, there was a difference in number of some peptide-immunoreactive fibers (SP,CGRP,VIP,and others). The increase of these immunoreactive fibers suggests that altered airway reflexes may be a feature of hypoxic adaptation. To clarify a physiological mechanism in the hypoxic adaptation, we are now studying an effect of intracellular second messengers, such as cyclic AMP and others, in axoplasmic transport of nerve fibers in unfixed sections of chronically hypoxic carotid body.

慢性缺氧大鼠颈动脉小体是感知动脉血氧张力的主要器官（380托，12周）。我们注意到慢性缺氧的两栖动物颈动脉迷路血管球细胞的一些超微结构特征：1)血管球细胞不完全覆盖，支持细胞大面积缺失，2)血管间基质中有细长的细胞质突起，3)血管球细胞与内皮细胞、周细胞和其他细胞紧密靠近。使用超高压电子显微镜（400kV）和半薄切片的三维分析清楚地表明，球囊细胞的不完全覆盖是基于球囊细胞和支持细胞之间肥大程度的差异。由于动脉PO_2普遍较低，这些超微结构的相似性可能是两栖动物适应缺氧的一般特征，有助于从血液中吸收氧气和向血液中释放儿茶酚胺。当比较常氧和慢性缺氧颈动脉体和气管中肽能纤维的分布和丰度时，发现一些肽免疫反应纤维（SP、CGRP、VIP等）的数量存在差异。这些免疫反应纤维的增加表明气道反射的改变可能是缺氧适应的一个特征。为了阐明低氧适应的生理机制，我们正在研究细胞内第二信使，如环AMP等，在慢性缺氧颈动脉体非固定部分神经纤维轴浆运输中的作用。