缓激肽抑制大鼠DRG分离神经元的GABA激活电流

INHIBTION OF GARA-ACTIVATED CURRENTS IN ISOLATED RAT DRG NEURONS BY BRADYKININ

本文应用全细胞膜片箝技术在新鲜分离的大鼠背根神经节（DRG）神经元上研究缓激肽（BK）对γ-氨基丁酸（GABA）反应的调制作用。结果发现：在34个对GABA反应的细胞中有31个细胞对BK敏感。在对BK敏感并引起内向电流的27个细胞中预加BK，对GABA-激活电流具有明显的抑制作用，如10-6mol／L的BK可抑制GABA（10-4mol／L）激活电流30％。BK可将GABA量效曲线明显下移，并抑制其最大反应达1／3以上，而不改变其Kd值。结果提示：BK能非竞争性地抑制GABA反应。

In the present paper, the modulation of GABA-activited currents by bradykinin (BK) was studied in DRG neurons freshly isolated from rat using whole－cell patch clamp techniques. Among the neurons (n=34)responding to GABA，27 were sensitive to BK．Pre－application of BK，eliciting an inward current alone, inhibited GABA-activated current markedly．For example, 10-6 mol/L BK suppressed GABAactivated current by aboot 30%．BK shifted the GABA dose-response curve downward obviously and depressed the maximal response to GABA by 1/3 or more while the Kd value was unchanged. The results suggest that BK inhibits GABA-activated current noncompetitively in rat DRG neurons.