腹外侧眶皮层内吗啡诱发的抗伤害效应的机制  

Mechanisms of morphine-induced antinociception in the ventrolateral orbi-tal cortex of the rat

作　　者：屈超玲[1] 贾红[1] 霍福权[1] 

机构地区：[1]西安交通大学医学院生理学与病理生理学系,教育部环境与基因相关疾病重点实验室,陕西西安710061

出　　处：《第四军医大学学报》2008年第1期5-8,共4页Journal of the Fourth Military Medical University

基　　金：国家自然科学基金(30570592);陕西省自然科学基金(2005C235)

摘　　要：目的:明确腹外侧眶皮层(VLO)内微量注射吗啡产生抗伤害效应的机制是否通过GABA能调制介导的.方法:以辐射热诱发的大鼠甩尾反射潜伏期的变化作为伤害性反应的指标.结果:VLO内微量注射选择性GABAA受体拮抗剂荷包牡丹碱(100,200,500ng)可剂量依赖性抑制辐射热诱发的大鼠尾反射潜伏期.VLO内微量注射吗啡(5.0μg)10min后,同一部位注射荷包牡丹碱(100ng)可增加吗啡诱发的抗伤害效应,而VLO内微量注射吗啡(5.0μg)10min后,同一部位注射GABAA受体激动剂muscimol(250ng)可减弱吗啡诱发的抗伤害效应.结论:VLO内GABAA受体参与吗啡诱发的抗伤害效应,吗啡可能直接抑制了GABA能中间神经元,使VLO至PAG的投射神经元去抑制,间接激活了脑干下行抑制,在脊髓水平抑制了伤害性信息的输入而实现的.AIM ： To examine whether γ-aminobutyric acid （GABA） modulation is involved in morphine-induced antinociception in the ventrolateral orbital cortex （VLO） of the rat. METHODS： Noxious heat-evoked tail flick latencies were measured in the lightly anesthetized rats. RESULTS： Microinjection of bicuculline （100, 200, 500 ng） , a selective GABAA receptor antagonist, into VLO depressed the radiant heat-induced tail flick reflex in a dose-dependent fashion. 100 ng bicuculline microinjected into the VLO sites where morphine （5.0 μg） had been microinjected 10 min earlier enhanced the morphine-evoked inhibition of the tail flick reflex, however, muscimol （250 ng）, a GABAA receptor agonist, microinjected into the VLO sites where morphine （5.0 μg） had been microinjected 10 min earlier attenuated the morphine-evoked inhibition of tail flick reflex. CONCLUSION： The GABAA receptors are involved in the modulation of VLO morphine-induced antinociception, which supports the hypothesis that morphine may directly inhibit the GABAergic inhibitory interneurons leading to indirect activation of the descending antinociceptive pathway through a disinhibitory effect on the VLO output neurons and depression of the nociceptire inputs at the spinal cord level.

关 键 词：吗啡 受体 GABA-A 腹外侧眶皮层 抗伤害效应 大鼠 

分 类 号：R338.2[医药卫生—人体生理学]