急性大鼠癫痫模型海马神经元原发性单位后放电脉冲间隔特征  

CHARACTERISTIC INTERSPIKE INTERVALS OF PRIMARY UNIT AFTERDISCHARGES IN HIPPOCAMPAL NEURONS OF EPILEPTIC RAT

作　　者：刘青[1] 吴俊芳[1] 汪胜[1] 胡玲[1] 覃星奎[1] 王文挺[1] 刁芳明[1] 韩丹[1] 

机构地区：[1]武汉大学医学院生理学系,武汉430071

出　　处：《生物物理学报》2005年第6期409-417,共9页Acta Biophysica Sinica

基　　金：湖北省自然科学基金资助项目(2003ABA123)

摘　　要：受到刺激后即刻出现的海马(hippocampus,HPC)原发性单位后放电是癫痫相关性细胞电活动的重要形式之一,其放电脉冲间隔(interspikeinterval,ISI)和串内平均频率(Hz)特征及其在网络癫痫形成中的作用值得探讨。实验用急性强直电刺激(60Hz,2s,0.4～0.6mA)大鼠右侧后背HPC(acutetetanizationoftherightposteriordorsalhippocampus,以后简称ATPDH)或右侧尾壳核(acutetetanizationoftherightcaudateputamennucleus,以后简称ATRC)诱导HPC或皮层网络癫痫,重点观察HPC神经元原发性单位后放电模式和上述的瞬时时间编码特征。结果表明:(1)HPC原发性单位后放电表现为两种不同的放电模式,即先易化后抑制或先抑制后易化,其ISI序列分别表现为先小后大的“头尾”式分布或先大后小的“尾头”式分布。(2)ATPDH主要引起“尾头”式(35/57串)、而ATRC主要引起“头尾”式(12/22串)ISI点分布的原发性单位后放电,串内“头”、“尾”平均持续时间均具有明显差异(P<0.05)。(3)ATRC可以诱导双侧HPC单位后放电出现交互的“头尾”、“尾头”式ISI点分布特征。(4)多串电刺激可以诱导HPC原发性单位后放电特征性ISI点分布重复显现。(5)特征性HPC原发性单位后放电伴随出现网络癫痫发作样高频电振荡。这提示:强直电刺激诱导的HPC神经元原发性单位后放电“头尾”或“尾头”式ISI序列分布规律,可以较准确地反映所记录神经元的诱发性易化或抑制活动的程度,用于网络癫痫形成中单个成员细胞癫痫相关性电活动机制的分析。Hippocampal primary unit afterdischarges induced by electric stimulation is one of the important pattern of activities related to rat epilepsy. The characteristics of its interspike intervals （ISI） and mean rate of the neuronal firing will be quantitatively analyzed. Acute tetanization （60 Hz, 2 s, 0.4-0.6 mA） of the right posterior dorsal hippocampus （ATPDH） or the right caudate putamen nucleus （ATRC） was used to induce electrogenic seizure-like activities. The results included： 1） Hippocampal primary unit afterdischarges manifested two patterns of firing rate changes： from facilitation to inhibition and from inhibition to facilitation; their ISI value changed from small to large, which take the shape of dense spots called “head” , and sparse spots called “tail” , or reversely; 2） Primary unit afterdischarges with “tail-head” distribution of ISI （35/57 trains） were mainly induced by the ATPDH; and the “head-tail” distribution of ISI （12/22 train） were mainly induced by the ATRC （P〈0.05）. 3） An interactive “head-tail” or “tail-head” ISI distribution was observed between bilateral hippocampal neuronal firing aiter the ATRC; 4） Hippocampal primary unit afterdischarges were closely related to seizure-like hippocampal EEG （70-150 Hz） or neocortical EEG （90-280 Hz） oscillations. It suggests that the hippocampal primary unit afterdischarges with “head-tail” or “tail-head” ISI distribution might reflect the level of tetani-evoked excitation or inhibition of neuronal firing, it might be helpful in analysis of the mechanism of epilepsy-related cellular activities in epileptic network.

关 键 词：单位后放电 放电脉冲间隔 海马 电振荡 电刺激 

分 类 号：Q424[生物学—神经生物学] R742.1[生物学—生理学]