Nathan T, Jensen M S, Lambert J D
PharmaBiotic Research Centre, University of Aarhus, Denmark.
Neurosci Lett. 1990 Mar 14;110(3):309-13. doi: 10.1016/0304-3940(90)90865-7.
Intracellular recordings were made from CA1 pyramidal neurones in the rat hippocampus slice preparation. The recording electrodes contained potassium acetate (4 M) with or without the quaternary lidocaine derivative, QX-314 (50 mM). Both fast (f) and slow (s) inhibitory postsynaptic potentials (IPSP) were evoked by low-frequency orthodromic stimulation. The s-IPSP was rapidly reduced by QX-314 injection. It decreased along a similar time course to the dV/dt of the action potential (AP). The f-IPSP and excitatory postsynaptic potential were not significantly reduced in size at a time when the s-IPSP was virtually abolished by QX-314. It is concluded that conductance through the K+ channels which are coupled to GABAB receptors is readily blocked by QX-314, while the Cl- channels which are coupled to GABAA receptors and the cation channels coupled to the glutamate receptors are relatively resistant to the local anaesthetic.
在大鼠海马脑片标本中对CA1锥体神经元进行细胞内记录。记录电极含有醋酸钾（4M），添加或不添加季铵利多卡因衍生物QX-314（50mM）。低频顺向刺激可诱发快速（f）和慢速（s）抑制性突触后电位（IPSP）。注射QX-314后，s-IPSP迅速降低。其下降的时间进程与动作电位（AP）的dV/dt相似。当s-IPSP实际上被QX-314消除时，f-IPSP和兴奋性突触后电位的大小没有显著降低。结论是，与GABAB受体偶联的K+通道的电导很容易被QX-314阻断，而与GABAA受体偶联的Cl-通道和与谷氨酸受体偶联的阳离子通道对局部麻醉药相对耐药。
