酒精依赖对大鼠边缘系统不同位置氨基酸含量的影响

Effect of ethanol dependence on amino acid levels in limbic system of rat brain

目的探讨酒精依赖对大鼠边缘系统的不同位置的谷氨酸(glutamic acid,Glu)、天门冬氨酸(aspartic acid,Asp)、γ-氨基丁酸(GABA)、丙氨酸(alanine,Ala)含量的影响,以期筛选出氨基酸受影响最明显的部位。方法利用6%的酒精含量的纯净水作为惟一饮用来源持续喂养25只大鼠4周,然后进行突然戒断筛选出形成酒精依赖的大鼠15只作为实验组,同时选择15只大鼠利用饮用水进行同期喂养作为对照组。断头取脑后选择左侧海马、扣带回、伏隔核和双侧杏仁核、丘脑前核组织,氨基酸分析仪测定各组部位的氨基酸递质含量变化,并分析Glu/GABA的比值变化。结果 4周后实验组酒精戒断评分在12分以上者占88%,戒断症状出现在停止饮用酒精饮料后11～27h。实验组杏仁核和丘脑前核的4种氨基酸与对照组比较均有统计学差异(P<0.05),海马部位实验组两种抑制性氨基酸均明显下降,实验组扣带回的GABA、Asp和伏隔核的Glu、Asp与Ala含量明显低于对照组。海马和杏仁核Glu/GABA含量实验组较对照组均有提高(P<0.05)。结论酒精依赖大鼠多个部位的氨基酸含量下降,其中海马和杏仁核的Glu/GABA增高,兴奋性相对增强。

Objective To investigate the effect of ethanol dependence on the amino acid neurotransmitters,including glutamic acid （Glu）,aspartic acid （Asp）,GABA,alanine （Ala） in limbic system of rats.Methods Rat model was reproduced by drinking 6％ ethanol liquid as exclusive drink continuously for 4 weeks,and 15 rats which came on obvious withdrawal symptoms were enrolled into test group,and another 15 rats which were bring up pure water for drinking for 4 weeks were grouped into control.All rats were killed to resect left hippocampus,cingulate gyrus and nucleus accumbens （NAc）,and bilateral amygdala and nucleus anterior thalamus（NAT） to test level of amino acid neurotransmitter by amino acid analyzer,and the ratio of Glu/GABA was analyzed in each part of 2 groups.Results 88％ of rats,which had drunk 6％ ethanol liquid for 4 weeks,appeared obvious withdrawal symptoms in 11-27 h after stopping ethanol consumption.There are significant difference in 4 kinds of amino acid content of amygdala and NAT between test group and control group,inhibitory amino acid content in hippocampus of test group was obviously lower than control group,also there were significant difference in GABA and Asp in cingulate gyrus and Glu,Asp and Ala in NAc between groups.Ratio of Glu/GABA was significant higher in hippocampus and amygdala in test group than control group.Conclusions For chronic ethanol drinking rats,there were lower amino acid level in many part of limbic system and Glu/GABA were obvious higher in hippocampus and amygdala compared with control group,which may connect with high brain excitation in this kind of rats.