急性热应激对小鼠大脑皮质GABA受体的影响

EFFECT OF ACUTE HEAT STRESS ON GABA RECEPTORS IN CEREBIAL CORTEX OF MICE

用放射配体结合分析方法和小鼠经受急性热应激致肛温达４２℃时的热应激模型，研究了小鼠大脑皮层中两类ＧＡＢＡ受体亚型（ＧＡＢＡＡ受体和ＧＡＢＡＢ受体）结合能力变化，以及氯丙嗪对ＧＡＢＡ受体的影响．通过Ｓｃａｔｃｈａｒｄ作图分析表明：１）急性热应激组小鼠大脑皮层ＧＡＢＡＡ受体Ｂｍａｘ值明显上调，而ＧＡＢＡＢ受体Ｂｍａｘ值则明显下调；２）氯丙嗪组小鼠大脑皮层ＧＡＢＡＡ受体增多出现上调现象，而ＧＡＢＡＢ受体则为下调；３）氯丙嗪热应激组小鼠大脑皮层的两类受体增多出现上调现象，且肛温明显低于４２℃．这些结果揭示：ＧＡＢＡ受体可能参予了热应激的调节过程，且两类不同受体有不同的作用方式，氯丙嗪也可能通过ＧＡＢＡ受体的介导，在改善热应激损伤中起主要作用．

The maximal ligand binding capcaity (Bmax) of GABA A and GABA B recepers in mouse cerebral cortex during the acute heat stress (Tr=42℃) was measured by radio-ligand assay(Scatchard assay).The effect of chiorpromazine (CPZ) on the Bmax of GABA A and GBAB B receptors was also studied. The results showed that:1)the Bmax of GABA A receptor (R A) upregulated.However,the Bmax of GABA B receptor (R B) was downregulated during the acute heat stress (HS); 2) the Bmax of R A was upregulated and the Bmax of R B was downregulated in CPZ-treated group;3)the Bmax of GABA receptors was upregulated in the heat stress after pre-treated CPZ group;the rectal temperature of CPZ group was sigmificantly lower than that of HS group. These results suggested that GABA receptors might be involved in the HS process and CPZ might attenuate the injury of HS through the regulation of GABA receptors function during HS.