急性分离的大鼠骶髓后连合核神经元由抑制性氨基酸诱导的电流反应(英文)

INHIBITORY AMINO ACID-INDUCED CURRENT RESPONSES IN ACUTELY ISOLATED RAT SACRAL DORSAL COMMISSURAL NEURONS

应用制霉菌素穿孔全细胞电压钳技术．在急性分离的大鼠骶髓后连合核（SDCN）神经元上，研究抑制性氨基酸诱导的反应的电生理学和药理学特性。当钳制电压为-40mV时，γ-氨基丁酸（GABA）、甘氨酸（Gly）和牛磺酸（Tau）均诱导产生内向电流。它们的EC50值分别是GABA5．2×10-5M，Gly4．0×10-5M及Tau1．6×10-4M。其Hill系数分别为GABA1．21，Gly1．27和Tau1．23。所有这些电流均在膜电位为-1．8mV左右时翻转。此外．Tau和Gly反应问还存在很强的交叉脱敏。结果提示，GABAA，Gly和Tau作为递质，通过受体Cl-通道复合体．在调节SDCN社经元伤害性传递中可能有重要作用。

The electrophysiological and pharmacological properties of inhibitory amino acid-induced responses were studied in neurons acutely dissociated from rat sacral dorsal commissural nucleus (SDCN) using nystatin perforated whole-cell patch recording configuration under voltage-clamp conditions. At a holding potential of -4o mV, γ-aminobutyric acid (GABA), glycine (Gly) and taurine (Tau) evoked inward currents. The currents increased in a sigmoidal fashion with increasing agonist concentration. The half-maximum concentration (EC50) values were 5. 2×10-6 M fOr GABA, 4. 0×10-5 M for Gly and 1. 6×10-4 M for Tau. The Hill coefficients of GABA-, Gly- and Tau-induced responses were 1. 21, 1. 27 and 1. 23, respectively. All these currents reversed near -1. 8 mV. More-over, a strong cross-desensitization between Tau and Gly response was observed. These results suggested that GABA, Gly and Tau acting through receptor-Cl channel complexes are likely to play an important role as transmit-ters in modulating nociceptive transmission in the SDCN.