海马脑片癫痫样放电时空特性的多电极记录研究

Exploring spatiotemporal patterns of epileptiform discharge in hippocampal slice using multi-electrode arrays

为了探索离体条件下癫痫样放电的时空特性,本研究采用多电极记录系统记录高钾人工脑脊液(artificial cerebrospinal fluid,ACSF)诱导的幼年大鼠海马脑片的自发放电活动。在成功诱导出癫痫样的簇样放电后,加入苯巴比妥钠以观察其对脑片各区域放电的压抑作用。结果显示:(1)高钾ACSF持续灌流脑片15min左右,多电极阵列上可记录到海马CA3(a^c)和CA1区反复出现同步节律的癫痫样簇样放电,与脑电信号中的发作间期痫性放电相似;定量分析结果提示,CA区各个亚区锥体细胞的活动特性无明显差异(P>0.05),而齿状回(dentate gyrus,DG)颗粒细胞层没有出现簇样放电,仅有少量动作电位发放,发放频率远低于CA区(P<0.05);(2)在持续高钾灌流下,稳定的簇样放电一旦建立即可至少持续40min;(3)簇样放电发放稳定后给予60μmol/L苯巴比妥钠,发现同步化放电的区域逐渐缩小,CA1和CA3c区的放电活动首先被压抑,而CA3a和b区的部分锥体细胞在加药10min后仍有较强的簇样放电。以上结果提示,多电极阵列能够有效地用于研究离体条件下癫痫样放电的时空特性,并可探索抗癫痫药对脑片不同区域癫痫样活动的作用。

To investigate the spatiotemporal properties of epileptiform activity in vitro,400 μm-thick transverse hippocampal slices were prepared from juvenile rat and planar multi-electrode array （MEA） containing 60 electrodes was used to record the electrical activity induced by bath application of high potassium artificial cerebrospinal fluid （ACSF） on slices.Following successful induction of epileptiform bursts,phenobarbital sodium was applied to test for its inhibitory effects on bursting activity in different regions of slice.Region-specific characteristics of epileptiform activity and anticonvulsant actions of phenobarbital sodium in the hippocampal network were determined by comparing the population activity obtained from MEA.The results showed that： （1） 15 min after high- K＋ ACSF application,rhythmic and synchronous epileptiform bursts could be detected from all CA sub-regions.Quantitative analysis indicates that the firing patterns of different CA sub-regions were not statistically different （P〉0.05）.However,no bursting activity was recorded from granular cells in dentate gyrus,only sparse spikes were observed,with frequency significantly lower than that in CA regions （P〈0.05）.（2） The high-K＋-induced bursting activity could last for more than 40 min with stable bursting activities.（3） Bath application of 60 μmol/L phenobarbital sodium inhibited the bursting activities on hippocampal slice.Bursting activities in CA3c and CA1 were firstly suppressed.10 min after the phenobarbital sodium application,strong bursting activities persisted only in some of pyramidal cells in CA3a and CA3b.These results show that MEA could be applied for studying the spatial and temporal properties of epileptiform activity in vitro,as well as the region-specific effects of anti-epileptic drugs.