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P物质对大鼠三叉神经节神经元GABA--和5--HT--激活电流的反向调制作用

胡旺平, 李之望, 茹立强, 樊友珍

华中科技大学同济医学院神经生物学系.湖北,武汉 430030

摘要

实验采用全细胞膜片钳技术观察P物质(SP)对大鼠同一三叉神经节(TG)神经元#gamma#--氨基丁酸激活电流(I_(GABA))和5--羟色胺激活电流(I_(5-HT))的调制作用。在受检的47个TG细胞中,多数情况下可在同一细胞记录到I_(GABA)和I_(5-HT)两种电流(63.8%,30/47)。在30个同时对GABA和5--HT敏感的细胞,其中22个细胞预加SP(0.01 #mu#mol)后,I_(GABA)减小(35.7±6.1)%,而I_(5-HT)增加(65.2±8.7)%。此种调制作用可被SP受体拮抗剂GR82334及胞内透析GDP--#beta#--S或GF109203X所阻断。以上结果表明:SP受体激活后经G蛋白耦联,通过相同的PLC--DAG--PKC转导途径对同一感觉神经元共存的GABA_(A)受体和5--HT_(3)受体产生相反的调制效应。

关键词： P物质; γ-氨基丁酸受体; 5-羟色胺_(3)受体; 调制; 细胞内透析; 三叉神经节; 大鼠

Opposite modulation effects of substance P on GABA-- and 5--HT--activated currents in the same sensory neurons

Hu Wangping, Li Zhiwang, Ru Liqiang, Fan Youzhen

Department of Neurobiology, Tongji Medical College, Huazhong University of Science and Technology.Wuhan 430030,Hubei

Abstract

The modulation by substance P of #gamma#-aminobutyric acid (GABA)- and 5-hydroxytryptamine(5-HT)-activated currents (I_(GABA) and I_(5-HT)) was studied using patch-clamp technique in rat trigeminal ganglion neurons. The majority of neurons examined responded to GABA and 5-HT with inward cuerrents(63.8%,30/47) in the same cell. In 22 out of 30 neurons sensitive both to GABA and to 5-HT,pretreatment with substance P (SP 0.01 #mu#mol) suppressed I_(GABA) by (35.7±6.1)% and enhanced I_(5-HT) by (65.2±8.7)%. GR 82334, a potent and specific antagonist of NK1 tachykinin receptor- reversibly blocked the modulatory effects of SP. The SP modulatory effect on I_(GABA) and I_(5-HT) was also almost abolished by intracellular dialysis of GDP-#beta#-S, a non-hydrolyzable GDP analog, or GF 109203X, a selective protein kinase C inhibitor. The results suggested that SP could exert opposite modulation of GABA_(A) receptor and 5-HT_(3) receptor activity in the same primary sensory neuron via the same intracellular signal transduction pathway.

Key words: substance P;#gamma#-aminobutyric acid;GABA_(A) receptor;5-hydroxytryptamine;5-HT_(3) receptor;modulation;intracellular dialysis

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引用本文：

胡旺平, 李之望, 茹立强, 樊友珍. P物质对大鼠三叉神经节神经元GABA--和5--HT--激活电流的反向调制作用[J]. 生理学报 2004; 56 (6): .

Hu Wangping, Li Zhiwang, Ru Liqiang, Fan Youzhen. Opposite modulation effects of substance P on GABA-- and 5--HT--activated currents in the same sensory neurons. Acta Physiol Sin 2004; 56 (6): (in Chinese with English abstract).