牛磺酸对大鼠背根神经节神经元GABA激活电流的调制作用

Modulatory effect of taurine on GABA-activated current in rat dorsal root ganglion neurones

牛磺酸可能是中枢神经系统中一种抑制性神经递质或神经调质。本实验目的在于观察牛磺酸是否引起背根神 经节（ＤＲＧ）神经元膜产生反应以及是否对ＧＡＢＡ引起的背根神经节神经元膜电流有调制作用。应用全细胞膜片钳 技术，观察未检测到牛磺酸（１０~－６～１０~－４ｍｏｌ／Ｌ）对ＤＲＧ神经元膜电流的改变，但预先给牛磺酸对ＧＡＢＡ（１０~－６～１０~－４ｍｏｌ／ Ｌ）激活的膜内向电流有明显的抑制作用，并具明显的浓度依赖性。如 １０~－５ｍｏｌ／Ｌ的牛磺酸可使 １０~－５ｍｏｌ／Ｌ ＧＡＢＡ激活 的膜电流抑制（４０％±５．９％，ｎ＝５）。牛磺酸对ＧＡＢＡ激活膜电流的抑制作用随预加牛磺酸与给予ＧＡＢＡ之间间隔时 间的延长而逐渐减弱，间隔８分钟左右，ＧＡＢＡ激活电流完全恢复。结果提示牛磺酸可能作为神经调质在初级感觉信 息传递中发挥重要的调制作用。

Taurine has been widely postulated to play a specific role as an-inhibitory neurotransmitter or neuromodulator. This study aimed to explore whether taurine could induce response of the membrane and whether GABA-activated current be mediated by taurine using whole-cell patch-clamp technique. The application of taruine (10^-6-10^-4mol/L) failed to change the membrane current in fat dorsal root ganglion neurones, but taurine was found to exert negative modulatory effects on GABA-activated current. In our experiment, GABA (10^-6- 10^-4mol/L) -activated current were attenuated markedly and reversibly by pre-application of taurine. The inhibitory effect of taurine (10`-6~ 10^-4mol/ L) on GABA (10^-6~ 10^-4mol/L ) -activated current was concentration dependent. The more the interval between pretreatment with taurine and the application of GABA was lengthened, the less inhibitory effect of taurine on GABA activated current would be. It took about 8 min to get a full recovery from taurine inhibition. Our observation suggested that taurine could be considered a good condidated for the endogenous neuromodulator on the primary afferent terminal of rat spinal cord.