Takahashi Y, Shirasaki T, Yamanaka H, Ishibashi H, Akaike N
Laboratory of Neuroinformation Science, Faculty of Liberal Arts, Tohoku Gakuin University, Sendai, Japan.
Brain Res. 1994 Mar 21;640(1-2):229-35. doi: 10.1016/0006-8993(94)91877-5.
The effects of glycine (Gly) and gamma-aminobutyric acid (GABA) on the neurons acutely dissociated from rat visual cortex (VC) were investigated in the whole-cell mode using a conventional patch-clamp technique. GABA and Gly evoked Cl- currents (ICl) in a concentration-dependent manner at a holding potential (VH) of -50 mV. The half maximum effective concentrations (EC50) were 4.64 x 10(-6) M for GABA and 6.67 x 10(-5) M for Gly. Strychnine and bicuculline reversively inhibited both 10(-5) M GABA- and 10(-4) M Gly-induced ICl in a concentration-dependent manner. The half maximum inhibitory concentrations (IC50) of strychnine on GABA- and Gly-induced currents were 4.00 x 10(-6) M and 8.26 x 10(-8) M, respectively. The IC50 values of bicuculline on GABA and Gly responses were 1.18 x 10(-6) M and 2.97 x 10(-4), respectively. GABA at 10(-5) M, which is near the EC50 of the GABA response, induced ICl in all neurons tested (n = 83). However, Gly of 10(-4) M, which is also near the EC50 of the Gly response, induced ICl in 34 out of 83 neurons tested (41%). Moreover, the maximum amplitude of the Gly response was about 60% of that of the GABA response. On the other hand, the enhancement of N-methyl-D-aspartate (NMDA, 3 x 10(-4) M) response by Gly (10(-6) M) was observed in all neurons (n = 36) whether they had the Gly-induced ICl or not.(ABSTRACT TRUNCATED AT 250 WORDS)
采用传统膜片钳技术的全细胞模式，研究了甘氨酸（Gly）和γ-氨基丁酸（GABA）对急性分离的大鼠视皮层（VC）神经元的影响。在-50 mV的钳制电位（VH）下，GABA和Gly以浓度依赖性方式诱发Cl-电流（ICl）。GABA的半数最大有效浓度（EC50）为4.64×10（-6）M，Gly为6.67×10（-5）M。士的宁和荷包牡丹碱以浓度依赖性方式可逆性抑制10（-5）M GABA和10（-4）M Gly诱导的ICl。士的宁对GABA和Gly诱导电流的半数最大抑制浓度（IC50）分别为4.00×10（-6）M和8.26×10（-8）M。荷包牡丹碱对GABA和Gly反应的IC50值分别为1.18×10（-6）M和2.97×10（-4）。10（-5）M的GABA接近GABA反应的EC50，在所有测试神经元（n = 83）中均诱发ICl。然而，10（-4）M 的Gly也接近Gly反应的EC50，在83个测试神经元中的34个（41%）中诱发ICl。此外，Gly反应的最大幅度约为GABA反应的60%。另一方面，无论神经元是否具有Gly诱导的ICl，在所有神经元（n = 36）中均观察到Gly（10（-6）M）增强N-甲基-D-天冬氨酸（NMDA，3×10（-4）M）反应。（摘要截断于250字）
