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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

Received: 　　Accepted:

Corresponding author: 刘玉珍　　E-mail: yuzhenliu@xxmu.edu.cn

Citing This Article：

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).