Effects of two volatile anesthetics and a volatile convulsant on the excitatory and inhibitory amino acid responses in dissociated CNS neurons of the rat.
Effects of two volatile anesthetics and a volatile convulsant on the excitatory and inhibitory amino acid responses in dissociated CNS neurons of the rat.
复制标题
两种挥发性麻醉剂和一种挥发性惊厥剂对大鼠离解中枢神经系统神经元兴奋性和抑制性氨基酸反应的影响。
作者：
M. Wakamori;Y. Ikemoto;N. Akaike
1.观察了两种挥发性麻醉剂[氟烷(Hal)和安氟醚(Enflurane)]和挥发性惊厥剂[六氟乙醚(HFe)]对大鼠孤束核分离神经元氨基酸诱发的膜电流的影响。分离的神经元采用全细胞膜片钳技术进行电压钳制。所有药物均采用微灌流系统，称为“Y管”方法。2.两种麻醉剂均能轻微降低谷氨酸(Glu)引起的兴奋性反应。Hal(10(-3)M)对Glu受体上三种激动剂的反应均受抑制，其抑制程度依次为：半定量>N-甲基-D-天冬氨酸>海人藻酸。HFE在2×10~(-3)M~(-3)时使Glu反应略有增加。两种麻醉剂均能增强GABA诱导的氯电流。其解离常数(Kd)分别为2.3×10~(-4)M和2.1×10~(-4)M，Hill系数分别为1.6和1.5。HFE抑制GABA反应，其Kd为8.7×10~(-5)M，Hill系数为0.84。4.Hal(10(-3)M)和Enf(10(-3)M)使GABA浓度-反应曲线的Kd分别从3.5×10(-6)M降至10(-6)M和1.9×10(-6)M，但不改变最大反应和Hill系数(1.5)。在HFe(10(-4)M)存在下，Kd增加到1.4×10(-5)M，Hill系数略有变化为1.2。
1. Effects of two volatile anesthetics [halothane (Hal) and enflurane (Enf)] and a volatile convulsant [hexafluorodiethyl ether (HFE)] on amino acid-induced membrane currents in neurons dissociated from the nucleus tractus solitarius of the rat were examined. The dissociated neurons were voltage clamped in the whole-cell mode of the patch-clamp technique. All drugs were applied with a microperfusion system, termed the "Y-tube" method. 2. The glutamate (Glu)-induced excitatory response was slightly reduced by both the anesthetics. The responses to three agonists at Glu receptor were depressed by Hal (10(-3) M) in the rank order of quisqualate greater than N-methyl-D-aspartate greater than kainate. HFE slightly increased the Glu response at a high concentration of 2 x 10(-3) M. 3. The gamma-aminobutyric acid (GABA)-induced chloride current (ICl) was enhanced by both anesthetics. The dissociation constant (Kd) for the enhancement was 2.3 x 10(-4) M for Hal and 2.1 x 10(-4) M for Enf, and the Hill coefficient was 1.6 for Hal and 1.5 for Enf. HFE depressed the GABA response with a Kd of 8.7 x 10(-5) M and a Hill coefficient of 0.84. 4. Hal (10(-3) M) and Enf (10(-3) M) decreased the Kd of the GABA concentration-response curve from 3.5 x 10(-6) to 10(-6) and 1.9 x 10(-6) M, respectively, without changing the maximum response or the Hill coefficient (1.5). In the presence of HFE (10(-4) M), the Kd was increased to 1.4 x 10(-5) M and the Hill coefficient was slightly changed to 1.2.(ABSTRACT TRUNCATED AT 250 WORDS)