新生期注射谷氨酸单钠对刺激下丘脑弓状核镇痛作用的影响  

EFFECT OF NEONATAL INJECTION OF MONOSODIUM GLUTAMATE ON THE ANALGESIA PRODUCED BY HYPOTHALAMIC ARCUATE NUCLEUS STIMULATION

作　　者：龚珊[1] 矫勇益[1] 殷伟平[1] 印其章[1] 

机构地区：[1]苏州医学院神经生物学研究室

出　　处：《神经科学》1994年第1期7-11,共5页Chinese Journal of Neuroscience

基　　金：国家自然科学基金

摘　　要：下丘脑弓状核（ＡＲＣ）是脑内β－内啡肽（β－ＥＮＤ）能神经元胞体集中的一个主要核团。新生期注射谷氨酸单钠（ＭＳＧ）能选择性地损毁ＡＲＣ中的神经元胞体而不累及路过纤维，是研究ＡＲＣ中神经元生理功能的一个良好模型。本实验利用这个实验模型研究刺激ＡＲＣ的镇痛效应。结果发现在这种ＭＳＧ处理的大鼠，刺激ＡＲＣ不再出现明显的镇痛效应（用电刺激鼠尾－嘶叫法测定）。这时脑室内注射β－ＥＮＤ（５μｇ／１０μｌ）能使刺激ＡＲＣ的镇痛效应恢复；若脑室注射多巴胺（ＤＡ，５μｇ／１０μｌ）不仅没有恢复作用，反而能削弱正常大鼠刺激ＡＲＣ的镇痛效应。实验结果提示，经ＭＳＧ处理的大鼠之所以不出现明显的镇痛效应，可能是由于ＡＲＣ中丧失了β－ＥＮＤ能神经元的结果，ＤＡ能神经元在其中不起重要作用。Hypothalamic arcuate nucleus(ARC) is the principal nucleus contaiaing β-endorphinergic (β-END) neurons in the brain. Neuronal cell bodies in ARC can be destroyed, hut sparing the fibers of passage, by neonatal administration of monosodium glutamate(MSG) in rats, which is a valuable model for studying the function of neurons in ARC. In the present experiment this model(MSG-treated rats) was used to investigate the analgesic effect of ARC stimulation by tail stimulation-vocalization test. It was found that no significant analgesic effect was observed after ARC stimulation in MSG-treated rats. The analgesic effect of ARC stimulation in MSG-treated rats could he recovered after intracerebroveotricular injection of β-END (5μg/ 10μl), hut not of dopamine(5μg/ 10μl), which on the contrary, could attenuate the analgesic effect of ARC stimulation in normal rats. Experimeotal results suggest that the disappearance of analgesic effect of ARC stimulation in MSG-treated rats might be the result of damage of β-END neurons in ARC, and no significant role could be attributed to dopaminergic neurons.

关 键 词：弓状核 谷氨酸单钠 Β-内啡肽 多巴胺 镇痛 

分 类 号：R338.3[医药卫生—人体生理学]