羟基马桑毒素所致的大鼠海马锥体细胞痫样放电活动  

Tutin-induced epileptiform discharge of CA1 pyramidal cells in rat hippocampal slices

作　　者：周华[1] 郑煜[1] 唐玉红[1] 

机构地区：[1]四川大学华西基础医学与法医学院生理学教研室,成都610041

出　　处：《生理学报》2004年第3期341-346,共6页Acta Physiologica Sinica

摘　　要：本研究采用离体海马脑片电生理研究技术,细胞外记录海马锥体细胞群体锋电位(population spike,PS),观察羟基马桑毒素(tutin)对大鼠海马脑片CA1区锥体细胞电活动的影响,探讨tutin是否具有致痛作用及其致痫机制。结果如下:(1)用40、30和20μg/ml浓度的tutin灌流海马脑片,可显著增高由顺向刺激Schaffer侧支所诱发的PS的幅度,灌流tutin 30min时,PS第一个波的幅度分别为对照的(388.7±20.1)%、(317.2±19.1)%和(180.9±11.6)%(各组n=5,P<0.05)。(2)伴随PS波幅的增高,可出现成串痫样放电波,波数4～11个不等。(3)灌流tutin后的部分脑片(n=9/34),在未刺激Schaffer侧支时也出现自发的成串、高幅痫样放电。(4)灌流CNQX阻断非NMDA受体后,再灌流tutin,PS幅度和放电波数均无显著性变化,即CNQX可完全抑制tutin所致的痫样放电;灌流AP-5阻断NMDA受体后,tutin仍可使PS幅度增高但放电波数无显著性增加,即AP-5可部分抑制tutin所致的痫样放电。上述结果表明,tutin可使海马脑片锥体细胞兴奋活动增强,具有致痫作用;兴奋性谷氨酸受体尤其是非NMDA受体可能介导tutin的致痫作用。Previous studies showed that a mixture, Coriaria Lactone (CL), extracted from a traditional Chinese herb Loranthus Parasiticus Mer, had a great excitatory influence on the nervous system, resulting in seizure. But what component in CL causes seizure is unclear. Tutin is a pure chemical component derived from CL. The present experiments were carried out to test if tutin has any epileptogenic action and to preliminarily study the mechanism underlying that action in vitro. The electrical activity of CA1 pyramidal cells, population spikes (PS), evoked by stimulation of the Schaffer collaterals in rat hippocampal slices was recorded extracellularly. The effects of tutin on the PS and the antagonistic actions of CNQX and AP-5 on the tutin-induced effects were investigated. The results are as follows. (1) Superfusion with 40, 30 and 20 μg/ml tutin caused significant increase in the amplitude and number of PS waves evoked by stimulating the Schaffer collaterals. Thirty minutes after superfusion of tutin, the amplitude of the first wave of the PSs was increased by (388. 7±0.1)%, (317.2±19.1)% and (180.9±11.6)% in each of the above three groups, respectively, compared with the control (for each group, n=5, P<0.05). (2) With increase in amplitude,the PS number was increased to 4～11 waves from a single wave in the control and manifested multiple epileptiform discharges 30 min superfusion with tutin. (3) Spontanous epileptiform discharges of CA1 pyramidal cells were obtained in 9 out of 34 cases after tutin superfusion. (4) The tutin-induced multiple epileptiform discharges of the CA1 pyramidal cells were completely blocked by CNQX, in aspects of both amplitude and number of the PS. Following the application of AP-5, the increase in the wave number of the tutin- induced epileptiform discharges was inhibited but the increase in the amplitude of the discharges was not significantly affected. These results

关 键 词：癫痫 羟基马桑毒素 海马脑片 痫样放电 NMDA受体 非NMDA受体 

分 类 号：R742.1[医药卫生—神经病学与精神病学]