电刺激右后背海马诱导双侧前背海马网络癫痫

BILATERAL ANTERIOR DORSAL HIPPOCAMPAL NETWORK SEIZURES INDUCED BY ACUTE TETANIZATION OF THE RIGHT POSTERIOR DORSAL HIPPOCAMPUS

目的 :急性强直电刺激右侧后背HPC诱导双侧HPC癫痫电网络形成的细胞机制。方法 :强直电刺激 (6 0Hz,2s,0 .4～ 0 .6mA)大鼠右后背HPCCA1基树突区 ,每隔 10min刺激一次 ,施加 10个刺激串。结果 :①分别抑制双侧CA1神经元单位放电频率 ,对侧的抑制效应更明显 (对侧 :6 2 .94 %± 3.6 8% ;同侧 :36 .6 1%± 3.14 % ,P <0 .0 1) ,出现抑制后爆发式放电。随着刺激串数的增加 ,抑制作用逐渐减弱。②同步原发性网络和单位后放电 ,以同侧CA1多见 (P<0 .0 1)。③ 90Hz或 12 0Hz原发性或继发性网络后放电仅仅累及同侧CA1。④对侧CA3基树突区网络与下托神经元单位放电出现同步继发性后放电 ,反复发作 ,持续约数小时。结论 :电刺激诱导的对侧HPC抑制后爆发式放电和长时程、反复发作的网络与单个神经元同步继发性后放电可能是跨半球癫痫网络形成的重要表现形式。

Aim: To investigate the neural network and cellular mechanisms of hippocampal epileptogenesis contralateral or ipsilateral to the side of acute tetanization(60 Hz,2 s,0.4～0.6 mA) of the posterior dorsal hippocampus (ATPDH). Methods: 10 trains of the ATPDH were administered into the CA1 basal dendritic region of the right hemisphere at an interval of 10 minutes. Results: ①The firing rate of CA1 single neuron in the right or the left hippocampus was inhibited respectively after the ATPDH,and the effects weakened gradually while the trains of the ATPDH increased. The inhibited firing rate and the transformed firing pattern from tonic one to clonic one were more obvious at the side contralateral to the stimulation(62.94%±3.68%,36.61%±3.14%,P<0.01). ②Synchronous primary afterdischarges of depth EEG and single unit discharges were more commonly observed at the side ipsilateral to the ATPDH (P<0.01). ③Primary or secondary hippocampal network afterdischarges at high frequency were only found in CA1 region ipsilateral to the ATPDH. ④Secondary afterdischarges of CA3 basal dendritic neural network were completely synchronized with those of subicular single neuron,which reoccured and persisted several hours. Conclusion: It is possible that post-inhibition bursting of single neuron and recurrent network seizures in the hippocampus contralateral to the artificial focus be the important manifestation of the formation of 'epileptic networks' across from one hemisphere to another.