Nuñez A, Buño W
Departamento de Morfologia, Facultad de Medicina UAM, Madrid, Spain.
Exp Neurol. 1992 Feb;115(2):266-70. doi: 10.1016/0014-4886(92)90061-t.
The effects of intracellular diffusion of the lidocaine derivative anesthetic QX-314 and of Cs+, which block Na+ and K+ conductances, respectively, were investigated in vivo in rat CA1 and CA3 pyramidal neurons to demonstrate slow Ca(2+)-related events. QX-314 loading prevented fast Na+ spikes, but slower presumably Ca2+ spikes remained. A slower and a faster duration type of QX-314-resistant spikes were observed. The former had high thresholds, while the latter was activated at moderate depolarized levels. The slower and the faster QX-314-resistant spikes fired at frequencies up to 8/s and 35/s and were 35-60 and 5-10 ms in duration, respectively. With Cs+ loading, pyramidal neurons depolarized and slow, presumably Ca2+, and fast Na+ spikes widened. Fast spikes usually showed a prominent shoulder and a slower repolarization. No differences were observed between drug effects in CA1 and CA3 neurons. In terms of their possible participation in theta rhythm genesis the slow QX-314-resistant events display the correct frequency and duration and can oscillate regeneratively.
在大鼠CA1和CA3锥体神经元中对利多卡因衍生物麻醉剂QX - 314以及分别阻断Na⁺和K⁺电导的Cs⁺的细胞内扩散效应进行了体内研究，以证明与Ca²⁺相关的缓慢事件。加载QX - 314可阻止快速Na⁺尖峰，但可能较慢的Ca²⁺尖峰仍然存在。观察到了两种持续时间类型的对QX - 314有抗性的尖峰，一种较慢，另一种较快。前者阈值较高，而后者在中等去极化水平时被激活。较慢和较快的对QX - 314有抗性的尖峰分别以高达8次/秒和35次/秒的频率发放，持续时间分别为35 - 60毫秒和5 - 10毫秒。加载Cs⁺后，锥体神经元去极化，缓慢的（可能是Ca²⁺的）和快速的Na⁺尖峰变宽。快速尖峰通常显示出一个明显的波峰和较慢的复极化。在CA1和CA3神经元中的药物效应未观察到差异。就它们可能参与θ节律的产生而言，对QX - 3有抗性的缓慢事件显示出正确的频率和持续时间，并且可以再生性振荡。
