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谷氨酸及其离子型受体激动剂抑制大鼠颈动脉体急性低氧应答反应

李超红^1,2, 刘玉珍^1,*

¹新乡医学院第一附属医院，河南省神经再生与修复重点实验室，生命科学研究中心，卫辉 453100；²重庆医科大学第二附属医院心血管内科，重庆 404100

摘要

本文旨在探讨谷氨酸及其离子型受体激动剂在大鼠颈动脉体急性低氧应答中的作用。SD大鼠麻醉后断头，游离双侧颈动脉分叉，置于持续灌流95% O2-5% CO2饱和的Kreb’s液的记录浴槽中，分离大鼠颈动脉体-窦神经复合体，窦神经中枢端放置吸附玻璃电极，记录窦神经基础放电。信号稳定后，给予5% O2-5% CO2-90% N2饱和的Kreb’s液灌流，观察颈动脉体对急性低氧的应答反应；通过灌流含有谷氨酸、谷氨酸离子型α-氨基-3羟基-5甲基-4异恶唑丙酸(α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid, AMPA)受体特异性激动剂AMPA或N-甲基-D-天冬氨酸(N-methyl-D-aspartate, NMDA)受体特异性激动剂NMDA的5% O2-5% CO2-90% N2饱和Kreb's液，观察谷氨酸、AMPA或NMDA在颈动脉体急性低氧应答反应中的作用。结果显示：谷氨酸(20 μmol/L)及其离子型受体特异性激动剂AMPA (5 μmol/L)、NMDA (10 μmol/L)均明显抑制急性低氧诱导的颈动脉体窦神经放电活性增强，且这种抑制作用均呈浓度依赖性。上述结果提示，激活谷氨酸离子型受体抑制大鼠颈动脉体对急性低氧的应答反应。

关键词： 颈动脉体; 急性低氧; 谷氨酸; 离子型谷氨酸受体

Glutamate and its ionotropic receptor agonists inhibit the response to acute hypoxia in carotid body of rats

LI Chao-Hong^1,2, LIU Yu-Zhen^1,*

¹The First Affiliated Hospital of Xinxiang Medical University, Henan Key Laboratory of Neural Regeneration and Repairment, Life Sciences Research Center, Weihui 453100, China；²Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 404100, China

Abstract

The purpose of this study was to investigate the effect of glutamate and its ionotropic receptor agonists on the response to acute hypoxia in rat carotid body in vitro. Briefly, after SD rats were anesthetized and decapitated, the bilateral carotid bifurcations were rapidly isolated. Then bifurcation was placed into a recording chamber perfused with 95% O2-5% CO2 saturated Kreb’s solution. The carotid body-sinus nerve complex was dissected, and the carotid sinus nerve discharge was recorded using a suction electrode. To detect the response of carotid body to acute hypoxia, the chamber was perfused with 5% O2-5% CO2-90% N2 saturated Kreb’s solution for a period of 100 s at an interval of 15 min. To observe the effect of glutamate, ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor agonist AMPA or N-methyl-D-aspartate (NMDA) receptor agonist NMDA on the response to acute hypoxia in rat carotid body, the chamber was perfused with 5% O2-5% CO2-90% N2 saturated Kreb’s solution containing the corresponding reagent. The results showed that glutamate (20 μmol/L), AMPA (5 μmol/L) or NMDA (10 μmol/L) inhibited the acute hypoxia-induced enhancement of carotid sinus nerve activity, and these inhibitory effects were dose-dependent. In summary, the activation of glutamate ionotropic receptors appears to exert an inhibitory effect on the response to acute hypoxia in carotid body of rats.

Key words: Carotid body; acute hypoxia; glutamate; ionotropic glutamate receptors

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通讯作者：刘玉珍　　E-mail: yuzhenliu@xxmu.edu.cn

引用本文：

李超红, 刘玉珍. 谷氨酸及其离子型受体激动剂抑制大鼠颈动脉体急性低氧应答反应[J]. 生理学报 2023; 75 (4): 537-543.

LI Chao-Hong, LIU Yu-Zhen. Glutamate and its ionotropic receptor agonists inhibit the response to acute hypoxia in carotid body of rats. Acta Physiol Sin 2023; 75 (4): 537-543 (in Chinese with English abstract).