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阿片受体在大鼠丘脑中央下核和顶盖前区前核介导电针镇痛中的不同作用

朱娟霞, 唐敬师, 贾红

西安交通大学医学院生理教研室,环境与疾病相关基因教育部重点实验室.陕西,西安 710061

摘要

该文旨在研究阿片受体是否参与丘脑中央下核(nucleus submedius,Sm)和顶盖前区前核(anterior pretectal nucleus,APtN)所介导的不同强度电针的镇痛作用。以辐射热诱发甩尾(tail flick,TF)反射潜伏期为伤害性反应的指标,观察了Sm和APtN 微量注射阿片受体拮抗剂纳洛酮对不同强度电针“足三里穴”(St. 36)抑制大鼠TF反射的效应。结果表明,Sm给予纳洛酮(1.0 #mu#g,0.5 #mu#l)阻断强电针(5 mA)对TF反射的抑制效应,而对弱电针(0.5 mA)的效应无明显影响;相反,APtN 给予纳洛酮阻断弱电针对TF反射的抑制效应,而对强电针的效应无明显影响;纳洛酮供给到Sm或APtN邻近其它脑区对强、弱电针的效应均无影响。这些结果提示,Sm内的阿片受体参与介导强电针兴奋细传入纤维(A--#delta#和C类)产生的镇痛,而APtN内的阿片受体则介导弱电针兴奋粗传入纤维(A--#beta#类)产生的镇痛。

关键词： 阿片受体; 纳洛酮; 丘脑中央下核; 顶盖前区前核; 电针镇痛; 甩尾反射

Differential effects of opioid receptors in nucleus submedius and anterior pretectal nucleus in mediating electroacupuncture analgesia in the rat

Zhu Juanxia, Tang Jingshi, Jia Hong

Department of Physiology, School of Medicine, Xi'an Jiaotong University, Key Laboratory of Environment and Genes Related to Diseases,Ministry of Education.Xi'an 710061,Shaanxi

Abstract

Previous studies have indicated that the thalamic nucleus submedius (Sm) and the anterior pretectal nucleus (APtN) are involved in the descending modulation of nociception. The aim of the present study was to examine whether the opioid receptors in the Sm and the APtN mediated the electroacupuncture (EA)-produced analgesia. The latency of tail flick reflex induced by radiant heat was used as an index of nociceptive response. The effects of microinjection of opioid receptor antagonist naloxone (1.0 #mu#g, 0.5 #mu#l) into Sm or APtN on the inhibition of the TF reflex induced by EA of “Zusanli” point (St. 36) with high- (5.0 mA) and low- (0.5 mA) intensity were examined in the lightly anesthetized rats. Sm microinjection of naloxone blocked the high- but not low-intensity EA-induced inhibition of the TF reflex. In contrast, naloxone applied to APtN blocked the low- but not high-intensity EA-induced inhibition. When naloxone applied to other brain regions adjacent to Sm or APtN, the EA-induced inhibition was not influenced under either high- or low-intensity condition. These results suggest that opioid receptors in Sm are involved in mediating the analgesia by high-intensity EA for exciting small (A-#delta# and C group) afferent fibers, while opioid receptors in APtN are involved in mediating the analgesia induced by low-intensity EA for only exciting large (A-#beta#) afferent fibers.

Key words: opioid receptor;Naloxone;nucleus submedius;anterior pretectal nucleus;Electroacupuncture analgesia;tail flick reflex

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引用本文：

朱娟霞, 唐敬师, 贾红. 阿片受体在大鼠丘脑中央下核和顶盖前区前核介导电针镇痛中的不同作用[J]. 生理学报 2004; 56 (6): .

Zhu Juanxia, Tang Jingshi, Jia Hong. Differential effects of opioid receptors in nucleus submedius and anterior pretectal nucleus in mediating electroacupuncture analgesia in the rat. Acta Physiol Sin 2004; 56 (6): (in Chinese with English abstract).