生理学报Acta Physiologica Sinica, June 25, 2003, 55(3)

研究论文

电刺激大鼠右后背海马诱导前背海马神经网络癫痫样电活动

王文挺1, 韩丹1,*, 邹祖玉2 ,曾俊2

武汉大学医学院 1生理学系、2病理学与病理生理学系, 武汉 430071

摘要: 本文旨在探讨单侧海马(hippocampus, HPC)内神经网络与HPC癫痫发生的关系及其细胞机制。实验在45只Sprague-Dawley大鼠上完成。急性强直电刺激大鼠右侧后背HPC CA1基树突区(acute tetanization of the posterior dorsal hippocampus, ATPDH; 60 Hz, 2 s , 0.4－0.6 mA)诱发HPC癫痫模型, 同步记录同侧前背HPC CA1顶树突区单位放电和基树突区深部电图。结果, ATPDH可以沿长轴向前1.8 mm处对前背HPC神经网络产生下述效应: (1)同步或非同步原发性单位与深部电图后放电, 在同步性后放电锁时(time-lock)关系明显。非同步性后放电的深部电图癫痫样电活动具有宽频带特征(5－90 Hz); (2)原发性单位后放-后抑制效应可以引发低频原发性电图后放电, 长时程爆发式单位放电可以诱发高频原发性电图后放电; (3)短束原发性电图后放电也可以诱发原发性单位后放电; (4)原发性电图后放电和神经元单位放电的抑制效应具有明显可塑性特征。以上结果提示, 重复施加ATPDH可以引起前背HPC癫痫相关性病理生理性神经网络的重建; 而单个神经元与神经网络的异常电活动之间具有明显的互动作用和突触传递可塑性特征; 沿HPC长轴内在抑制性通路的过度活动也可以诱发电图癫痫样电活动, 导致HPC网络癫痫的发生。

关键词: 深部电图; 单位放电; 神经网络; 强直电刺激; 海马; 癫痫

中图分类号: Q424; R742.1

Epileptiform activity of the anterior dorsal hippocampal network induced by acute tetanization of the right posterior dorsal hippocampus of the rat

WANG Wen-Ting1, HAN Dan1，*, ZOU Zu-Yu2, ZENG Jun2

Departments of1Physiology, 2Pathology and Pathophysiology, Medical College, Wuhan University, Wuhan 430071

Abstract: The purpose of the present work was to study the role of unilateral hippocampal neural network in hippocampal epileptogenesis and its cellular mechanisms. Experiments were performed on 45 Sprague-Dawley adult rats. Acute tetanization (60 Hz, 2 s, 0.4－0.6 mA) of the right posterior dorsal hippocampus (ATPDH) was used to induce hippocampal epilepsy. The single unit discharges and the depth electrographs were synchronously recorded with a glass microelectrode and a pair of stainless concentric electrodes in the ipsilateral anterior dorsal hippocampus (HPC). The results demonstrated that: (1) some primary unit after-discharges were synchronized with electrographic after-discharges in the anterior dorsal HPC network after eight or nine tetanic trains were administered. Others desynchronized with 5－90 Hz primary depth electrographic after-discharges; (2) primary electrographic after-discharges were driven by primary unit after-discharges in the anterior dorsal HPC; (3) primary unit after-discharges were induced by brief primary electrographic after-discharges; and (4) plasticity of primary electrographic after-discharges and inhibition of single neuron firing were induced by repetitive ATPDH. The results suggest that hippocampal pathophysiologic network along the temporal-septal axis of the HPC is re-established by the repetitive ATPDH. There are plastic interactions between single neurons and its network during this re-establishment, which may be involved in the generation of “seizure oscillation”. Over-activation of an intrinsic inhibition of the HPC along its temporal-septal axis might be involved in hippocampal network epileptogenesis.

Key words: electroencephalography; single unit discharges; neural networks; tetanus; hippocampus; epilepsy