生长抑素对实验性癫痫大鼠海马CA1区的作用

The role of somatostatin in area CA1 of rat hippocampus in experimental epilepy

在大鼠海马CA1区微量注射 0 0 3～ 0 3nmol生长抑素 (somatostatin ,SS)后 ,皮层脑电出现单个或成串的棘尖波 ,平均脑电总功率显著升高 ,并且在一定范围内 ( 0 0 0 6～ 0 15nmol)具有剂量依赖性。在海马CA1区微量注射0 0 3～ 0 3nmolSS可诱发大鼠表现出痫样行为 ,并可加重红藻氨酸诱导的大鼠痫样活动。在 95个大鼠海马脑片上细胞外记录SS对CA1区青霉素诱导的 114个痫样放电单位的影响 ,SS ( 10 -10 ,10 -8,10 -6mol/L)引起 5 9 0 5 %的痫样单位放电频率显著增加 ,2 1 90 %的痫样单位放电频率显著减少 ,提示SS在海马CA1区的作用以促进痫样放电为主。SS抗体 ( 1∶10 0 0 )可部分阻断青霉素诱导的CA1区痫样放电 。

In area CA1, intrahippocampal microinjection of somatostatin(SS, 0 03 to 0 3 nmol) caused single or a series of spike sharp waves in the cortex electroencephalogram (EEG), the spectrum average total power of which is increased dose dependently from 0 006 to 0 15 nmol. Microinjection of SS into the hippocampal CA1 subregion brough out epileptic like behavioral responses and aggregated kainic acid (KA) induced epileptiform activity of rats. With extracellular recording technique, the effects of SS on 114 units epileptiform discharge were investigated in penicillin (PEN) treated 95 rat hippocampal slices. In response to the application of SS (10 -10 , 10 -8 , 10 -6 mol/L), the burst frequency of area CA1 62/105 (59 05%) recorded unit discharges was increased significantly, while that of 23/105 (21 9%) was decreased. These results suggest that SS in hippocampal CA1 subregion mainly precipitates epileptiform discharge. The addition of anti somatostatin antibody (1∶1?000) to the perfusate partly blocked the epileptiform bursts triggered by PEN perfusion, while this antiepileptic effect of SSAB was reversed by application of SS (10 -8 mol/L). These indicate that endogenous SS may be involved in epileptiform discharge in area CA1 of hippocampus.