摘要
目前已普遍认为牛磺酸可能是中枢神经系统中的一种抑制性神经递质或神经调质。本实验的目的在于观察牛酸是否使背根神经节神经元膜产生电位变化及其是否对GABA引起的背根神经节神经元膜去极化有调制作用。应用细胞内记录技术观察，标本灌流液中滴加牛磺酸（0．1～100μmol／L）未记录到可检测的膜电位改变，但牛磺酸对GABA（0．3～1000μmol／L）引起的去极化有明显的抑制作用，并对GABAA受体特异性激动剂muscimol（10～100μmol／L）和isoguvacine（10～100μmol／L）引起的去极化有同样的抑制作用，此作用具有明显的浓度依赖性。如10μmol／L的牛磺酸可使100μmol／LGABA引起的去极化抑制47．2％±13．8％（n=8）。牛磺酸对GABA引起去极化的抑制作用随预加牛磺酸与外加GABA之间间隔时间的延长而逐渐减弱，约间隔8～10min，GABA引起的去极化完全恢复。结果提示，牛磺酸在脊髓背角信息传递中起重要的调制作用。
Taurine has been postulated to play a speific role as an inhibitory neurotransmitter or neuromodulator. This study aimed to explore whether chorine could induce changes in membrane Potential and whether GASA-induced depolarization was modulated by taurine using intracellular recordings. Drop application of taurine(0. 1~ 100 μmol/L) failed to change the membrane Potential in rat dorsal root ganglion neurones, but taurine was found to exert negative modulatory effects on the responses mediated by GABAA receptor. In our experiment with intracellular recording,GallA (0. 3~ 1 000 mol/L)-, muscimol (10~ 100 pool/L)- and isoguvacine (10~ 100 μmol/L)-induced depelarization were attenuated markedly and reversibly by pre-application of taurine (100 mol/L). The inhibitory effect of taurine (0. 1 ~ 100mool/L) on GABA (100mol/L)-induced membrane depolarization was concentration dependent. The more the interval between pretreatment with taurine and the application or GAGA was lengthened,the less inhibitory effect or taurine on GABA-induced depolarization would be. It took about 8-10 min to get a full recovery from taurine inhibition. Our observation suggested that taurine could be considered a good candidate for the endogenous neuromodulator on the primary afferent terminal of rat spinal cord.
关键词
牛磺酸
Γ-氨基丁酸
去极化
背根神经节
调制
taurine
GABA
depolarization
dorsal root ganglion
intracellular recording
modulation
rat
