糖皮质激素对谷氨酸和DGABA受体的电生理反应的快速调制作用

FAST MODULATION OF GLUTAMATE AND GABA RECEPTORMEDIATE ELECTROPHYSIOLOGICAL RESPONSES BY GLUCOCORTICOID

在大鼠下丘脑薄片和豚鼠腹腔神经节上，分别用玻璃微电极细胞外和细胞内记录方法，观察了１０－６ｍｏｌ／Ｌ糖皮质激素（ＧＣ）对谷氨酸和ＧＡＢＡ受体介导效应的快速调制作用。结果表明，ＧＣ灌流后５ｍｉｎ，对谷氨酸受体介导的效应起抑制作用，而对ＧＡＢＡ受体介导的效应起增强作用。撤除ＧＣ后，神经元对谷氨酸和ＧＡＢＡ的反应恢复到对照水平。低钙高镁灌流液不能取消ＧＣ的调制作用。结果提示，ＧＣ在不需要突触环路条件下，可能通过非基因组途径影响谷氨酸和ＧＡＢＡ受体介导的效应。

Fast modulation by glucocorticoid on gluatmate and GABA receptor-mediated electrophysiological responses was investigated by extracellular iontophoresis and intracellular techniques in rat hypothalamic brain slices and guinea pig coeliac ganglion preparatins respectively. The results were as follows: Glucocorticoid inhibited the glutamatereceptor-mediated excitatory response and potentiated the GABA receptor-mediated inhibitory response within 5 min after perfusion. All these responses are reversible afterremoval of the glucocorticoid. Low Ca2+ high Mg2+ medium was ineffective to blockthe fast modulatory effects of glucocorticoid on the gluatmate and GABA receptor-mediated responses. It appears that the latter responses are mediated through some non-genomic mechanism without an involvement of synaptic circuitry.