褪黑素对谷氨酸钠致痫大鼠海马5-羟色胺水平的影响

目的观察褪黑素(Melatonin,MT)对谷氨酸钠(Glutamate,Glu)致痫大鼠海马5-羟色胺(5-hydroxytryptamine,5-HT)水平的影响,研究其抑制癫痫的作用机制。方法40只健康雄性SD大鼠随机分为4组(每组10只),分别为生理盐水对照组(NS组);谷氨酸钠致痫组(Glu组);褪黑素 谷氨酸钠组(MT Glu组);Luzidole 褪黑素 谷氨酸钠组(Luz MT Glu组)。观察并记录大鼠行为学及脑电图改变,用免疫组织化学方法检测大鼠海马内5-HT含量变化。结果行为学观察和EEG显示,NS组无痫样发作和痫样放电,Glu组和Luz MT Glu组痫样发作重(Ⅲ-Ⅴ级),脑电图显示频发高幅的痫样波,TM Glu组无或仅有轻微发作(0-Ⅱ级),脑电图上无或偶见散在单个微小痫样波;免疫组织化学分析结果显示,Glu组和Luz MT Glu组大鼠海马内5-HT含量与对照组比较均减少,差异性明显(P<0.05),MT Glu组较Glu组和Luz MT Glu组5-HT含量升高,差异性明显(P<0.05)。结论MT对谷氨酸钠致痫大鼠痫样发作程度、痫样放电有抑制作用,其机制之一是经由其特异性的膜受体,通过某种机制增强5-HT作用,进而发挥抑痫效应。

THE EFFECT OF MELATONIN ON 5-HT LEVEL IN HIPPOCAMPUS OF RATS WITH SEIZURES INDUCED BY GLUTAMATE

Objective To observe the effect of melatonin on 5-HT expression in the hippocampus of rats with seizures induced by glutamate,and to explore the role of melatonin in epileptogenesis.Methods Forty male adult SD rats were randomly divided into four groups: control group(n=10),L-glutamate group(n=10),melatonin intervening group(n=10) and luzidole melatonin L-glutamate group.The behavior and electroencephalogram(EEG) of rats were observed and recorded.The level of 5-HT in the hippocampus was demonstrated with immunohistochemistry.Results The control group showed no seizure activity and epileptic spikes,and the melatonin intervening group showed no or weak seizure activity and sporadic epileptic spike,but the other two groups had severe seizure activities and high amplitudes.The level of 5-HT in the L-glutamate group and luzidole melatonin L-glutamate group was much weaker than that of the control group,especially in the hippocampal area CA3(P<0.05).And the level of 5-HT in melatonin intervening group was much higher than that of the L-glutamate group and luzidole melatonin L-glutamate group(P<0.05).Conclusion Melatonin can alleviate the seizure activities induced by L-glutamate.This effect may be due to its potentiation of the effect of 5HT via its specific membrane receptors.