P物质对GABA_A受体介导电流的作用  

Effect of SP on GABA-Activated Currents from Rat Dorsal Root Ganglion

作　　者：张志琴[1] 李春霞[1] 王丽凤[1] 呼海燕[1] 张凤杰[1] 赵磊[1] 李丽[1] 司军强[1] 

机构地区：[1]石河子大学医学院医学系,新疆石河子832002

出　　处：《石河子大学学报（自然科学版）》2003年第3期177-181,共5页Journal of Shihezi University(Natural Science)

基　　金：国家自然科学基金(39860027;30160026)

摘　　要：应用全细胞膜片箝技术,在大鼠新鲜分离的背根神经节细胞上观察到:SP对GABA激活电流有调制作用。实验结果表明:多数受检的大鼠背根神经节神经元对SP(28/41,68.5％)和GABA(36/41,88.2％)敏感,100μmol/LSP和100μmol/L GABA激活内向电流的幅值分别为243.8±82.7pA(x±s,n=9)和1.76±0.48nA(x±s,n=13)。GABA与SP激活的内向电流明显不同,前者具有明显的去敏感现象。实验预加SP(0.001～1μmol/L)30s后再加GABA,则GABA激活电流的幅值明显减小,而且GABA激活电流减小的程度与预加SP的浓度呈量效依赖关系。SP主要抑制GABA激活电流的峰电流,对其稳态电流的抑制不明显。预加0.1μmol/L SP之后约4min左右,SP对GA-BA激活电流的抑制效率最大,为49.8±7.2％(x±s,n=7,P≤0.01),而预加SP 12min之后,SP才失去对GABA激活电流的抑制作用。The whole-cell patch-clamp technique was used to record SP- and GABA-activated currents in neurons freshly dissociated from rat dorsal root ganglion neurons. It shows in the present study that application of substance P (28/41, 68.5%) and GABA (36/41, 88. 2%) can induce concentration-dependency inward current in some cells. SP-( 10-4 mol/L) and GABA (0.0001 mol/L) -activated inward currents are 243.8 ± 82.7 pA ( x ±s , n, = 9) and 1.76±0.48 nA (x± s,n = 13), respectively. It is different from SP- and GABA-activated currents, GABA-activated current has de-sensitization. However, pre-application of SP (0.001 -1/μmol/L)can inhibit the GABA-activated inward current which is identified to be GABAA receptor-mediated current. The inhibitory effects are concentration-dependent. GABA-activated current has three processes,the peak value (Ip) ,the steady state (Iss) and the desensitization (Id) .The desensitization of GABA-activated current is a biphasic process, including fast and slow desensitization. The effect of SP on the peak value GABA-activated current is more obvious than the steady state of GABA-activated current.The inhibition of GABA-activated current by SP(0.01 μmol/L)is related to the time after application of SP,it reaches the peak al about 4 min (49. 8±7.2%,x±s,n=7,P≤0.01) and took about 12 tnin to get a full recovery.

关 键 词：P物质 GABAA受体 介导电流 全细胞膜片箝技术 背根神经节 调制作用 

分 类 号：R338.8[医药卫生—人体生理学]