[Epileptiform activity of the anterior dorsal hippocampal network induced by acute tetanization of the right posterior dorsal hippocampus of the rat].
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.
Wang
Wen-Ting
WT
Department of Physiology, Medical College, Wuhan University, Wuhan 430071.
Han
Dan
D
Zou
Zu-Yu
ZY
Zeng
Jun
J
D000818:Animals; D004558:Electric Stimulation; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005071:Evoked Potentials; D006624:Hippocampus / Q000503:physiopathology*; D008297:Male; D009415:Nerve Net / Q000503:physiopathology*; D009474:Neurons / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley