Otsuka H, Yamamura T, Hanaoka Y, Kemmotsu O
Department of Anesthesiology, Hokkaido University School of Medicine, Sapporo, Japan.
J Anesth. 1992 Jul;6(3):305-11. doi: 10.1007/s0054020060305.
The effects of propofol on synaptic transmission were characterized and compared with pentobarbital in the rat hippocampal slice preparation. Hippocampal CA1 population spike after stimulation of Schaffer collaterals indicated that the postsynaptic response was primarily mediated by non-N-methyl-D-aspartate class glutamate receptors since it was abolished by the presence of 6,7-dinitroquinoxaline-2,3-dione (DNQX). Propofol and pentobarbital depressed CA1 population spike amplitude in a dose dependent fashion. Dose-response curves for population spike amplitudes were determined for propofol and pentobarbital and the concentrations producing a half-maximum response (ED(50)) were 110 microM and 160 microM for propofol and pentobarbital, respectively. By contrast, when GABA A-mediated inhibition was blocked by addition of 100 microM pictotoxin, propofol, in concentrations up to 400 microM had no significant effect on population spike amplitudes. These results suggest that propofol attenuates synaptic transmission in the central nervous system in part by enhancing GABA A-mediated inhibition and not by depressing glutamate-mediated excitation, as occurs with pentobarbital.
在大鼠海马脑片制备中，对丙泊酚对突触传递的影响进行了表征，并与戊巴比妥进行了比较。刺激Schaffer侧支后海马CA1群体峰电位表明，突触后反应主要由非N-甲基-D-天冬氨酸类谷氨酸受体介导，因为它在6,7-二硝基喹喔啉-2,3-二酮（DNQX）存在时被消除。丙泊酚和戊巴比妥以剂量依赖性方式降低CA1群体峰电位幅度。测定了丙泊酚和戊巴比妥的群体峰电位幅度剂量-反应曲线，产生半数最大反应（ED50）的丙泊酚和戊巴比妥浓度分别为110微摩尔和160微摩尔。相比之下，当通过添加100微摩尔荷包牡丹碱阻断GABAA介导的抑制作用时，高达400微摩尔浓度的丙泊酚对群体峰电位幅度没有显著影响。这些结果表明，丙泊酚部分通过增强GABAA介导的抑制作用而非像戊巴比妥那样抑制谷氨酸介导的兴奋作用来减弱中枢神经系统中的突触传递。
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