去甲肾上腺素引起蟾蜍背根神经节神经细胞膜电位变化的离子机制  

IONIC MECHANISM OF NORADRENALINE-INDUCED MEMBRANE POTENTIAL CHANGES OF NEURONES IN TOAD DORSAL ROOT GANGLION

作　　者：王阿敬[1] 李之望[1] 胡谋先[1] 王士端[1] 冷明 

机构地区：[1]同济医科大学实验医学研究中心

出　　处：《生理学报》1989年第2期145-152,共8页Acta Physiologica Sinica

基　　金：国家自然科学基金;项目编号:3860571

摘　　要：本文应用细胞内记录方法,对去甲肾上腺素(NA)引起蟾蜍背根神经节(DRG)神经细胞膜电位去极化或超极化反应时的膜电导及翻转电位值进行了测量,并观察了钾和钙离子通道阻断剂灌流DRG对NA引起膜电位反应的影响。当NA引起去极化反应时,15个细胞的膜电导减小32.6％。少数细胞膜电导开始增加,继而减小(n=4)。NA超极化反应时膜电导增加13.2％(n=8)。NA去极化反应的翻转电位值为-88.5±0.9mV((?)±SE,n=4),NA超极化反应在膜电位处于-89至-92mV时消失。 钾通道阻断剂四乙铵可使NA去极化幅值增加73.7±11.9％((?)±SE,n=7),并使NA超极化幅值减小40.5％(n=4)。细胞内注入氯化铯使苯肾上腺素去极化幅值增加34.5％(n=4)。钙通道阻断剂氯化锰使NA去极化及超极化反应分别减小50.5±9.9％((?)±SE,n=10)和89.5±4.9％((?)±SE,n=7)。结果提示,NA引起DRG神经细胞膜电位的去极化或超极化反应,可能与膜的钾及钙通道活动的改变有关。The membrane conductance and reversal potential were determined for neurones in toad dorsal root ganglion (DRG) with intracellular recording technique during depolarization or hyperpolarization induced by noradrenaline (NA). The effects of blocking agents for potassium or calcium channels on NA-induced membrane potential responses were examined.In 15 neurones, the NA-induced depolarization was accompanied by a 32.6% decrease of membrane conductance; in other 4 neurones, the depolarization was accompanied by an initial increase and subsequent decrease in membrane conductance. The NA hyperpolarization was associated with an increase of membrane conductance by 16.2% (n=8). The mean reversal potential of NA-induced depolarization was -88.5±0.9mV (n=4). The NA-induced hyperpolarization was nullified at -89 to -92mV of membrane potentials (n=3). Tetraethylammonium superfusion enhanced NA depolarization amplitude by 73.7 ±11.9% (n=7) and depressed NA hyperpolarization amplitude by 40.5% (n=4). Intracellular injection of CsCl increased phenylephrine-induced depolarization by 34.5% (n=4). MnCl_2 superfusion decreased the amplitudes of NA-induced depolarization by 50.5±9.9%(n=10), and of NA-induced hyperpolarization by 89.5±4.9% (n= 7) respectively. The results suggest that the depolarization or hyperpolarization induced by NA might be mediated by the alteration in activition of K^+ or Ca^(2+) channels. noradrenaline; dorsal root ganglion; α-adrenoceptor; membrane conductance

关 键 词：去甲肾上腺素 背根神经节 膜电导 

分 类 号：Q42[生物学—神经生物学]