Jarolimek W, Misgeld U
Abteilung Neurophysiologie, Max-Planck-Institut für Psychiatrie, Martinsried, F.R.G.
Neurosci Lett. 1991 Jan 2;121(1-2):227-30. doi: 10.1016/0304-3940(91)90691-l.
The action of the non-N-methyl-D-aspartate (non-NMDA) receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) on gamma-aminobutyric acid-A (GABAA) receptor-mediated currents was studied in dissociated rat midbrain and hypothalamic cultures using whole-cell recording. Spontaneous synaptic activity consisted of excitatory (EPSCs) and inhibitory postsynaptic currents (IPSCs). Bicuculline (20 microM) blocked IPSCs and increased the frequency of EPSCs. CNQX (1 microM) reduced both EPSCs and IPSCs. In the presence of 0.3 microM tetrodotoxin (TTX), CNQX (1-20 microM) blocked miniature EPSCs and reduced IPSCs. In TTX, increasing K+ (20 mM) evoked EPSCs and IPSCs in a Ca-dependent manner. CNQX (10 microM) blocked evoked EPSCs and diminished evoked IPSCs similarly as miniature IPSCs. Muscimol-(0.2-5 microM) induced currents were dose-dependently reduced by CNQX (10-50 microM). It is concluded that CNQX reduces GABAA receptor-mediated inhibition primarily by reducing the excitatory drive in the evolving network, but, in addition, has a significant blocking effect on the GABAA receptor-channel complex.
使用全细胞记录法，在大鼠中脑和下丘脑分离培养物中研究了非N-甲基-D-天冬氨酸（non-NMDA）受体拮抗剂6-氰基-7-硝基喹喔啉-2,3-二酮（CNQX）对γ-氨基丁酸-A（GABAA）受体介导电流的作用。自发突触活动包括兴奋性突触后电流（EPSCs）和抑制性突触后电流（IPSCs）。荷包牡丹碱（20微摩尔）阻断IPSCs并增加EPSCs的频率。CNQX（1微摩尔）同时降低EPSCs和IPSCs。在存在0.3微摩尔河豚毒素（TTX）的情况下，CNQX（1 - 20微摩尔）阻断微小EPSCs并降低IPSCs。在TTX存在下，增加钾离子（20毫摩尔）以钙依赖的方式诱发EPSCs和IPSCs。CNQX（10微摩尔）阻断诱发的EPSCs并类似地减少诱发的IPSCs，如同微小IPSCs一样。蝇蕈醇（0.2 - 5微摩尔）诱导的电流被CNQX（10 - 50微摩尔）剂量依赖性地降低。得出的结论是，CNQX主要通过减少正在发育的网络中的兴奋性驱动来降低GABAA受体介导的抑制作用，但此外，对GABAA受体 - 通道复合物具有显著的阻断作用。
