摘要
目的:观察多巴胺对正常及急性吗啡成瘾大鼠尾核中痛兴奋神经元电活动的影响,从而进一步探讨多巴胺和尾核在吗啡成瘾大鼠痛觉调制中的作用。方法:实验于2005-05/11在哈尔滨医科大学神经痛觉电生理研究室完成。①52只Wistar大鼠随机分为2组:正常对照组26只(又分为生理盐水组6只、多巴胺组20只)及吗啡成瘾组26只(又分为生理盐水组6只、多巴胺组20只)。②模型制备:大鼠背部皮下递增注射吗啡剂量,依次为:5,10,20,40,50mg/kg,3次/d(8:00,12:00,16:00),连续给药5d,建立吗啡成瘾大鼠的模型。正常对照组大鼠背部皮下注射生理盐水,时间、剂量均与吗啡成瘾组相同。第6天8:00观察大鼠的自然戒断症状30min后开始实验。③实验以电脉冲刺激大鼠坐骨神经作为伤害性痛刺激,用玻璃微电极记录尾核中痛兴奋神经元的放电,观察侧脑室注入多巴胺对痛兴奋神经元电活动的影响。结果:52只大鼠均进入结果分析。①多巴胺可提高正常大鼠尾核中痛兴奋神经元的兴奋性,即22个痛兴奋神经元平均秒净增值比注射多巴胺前(100%)增加了(131.8±10.3)%,潜伏期缩短了(55.6±6.3)%。②多巴胺使吗啡成瘾大鼠17个痛兴奋神经元的兴奋性降低,17个痛兴奋神经元的平均秒净增值比注药前(100%)降低了(74.8±7.6)%,潜伏期延长了(82.1±8.3)%。结论:多巴胺可使正常大鼠尾核中痛兴奋神经元对电刺激的兴奋性增强,呈易化疼痛,而对吗啡成瘾大鼠尾核中痛兴奋神经元有抑制作用,表现为镇痛效应。
AIM： To study the effects of dopamine on the electrical activities of pain excitation neurons in the caudate nucleus of normal and morphinistic rats, accordingly further investigate the modulation of dopamine and caudate nucleus on central painful sense of morphinistic rats.
METHODS： The experiment was carried out in the research room of nerve painful electrophysiology between May and November 2005. （1） Fifty-two Wistar rats were randomly divided into normal cantrol group （n=26）, which was subdivided into saline group （n=6） and dopamine group （n=20）, and morphinistic group （n=26）, which was subdivided into saline group （n=6） and dopamine group （n=20）. （2） Model establishment： The morphinistic rat models were induced by subcutaneous injection of morphine on the back with gradually increasing dosages of 5, 10, 20, 40 and 50 mg/kg, three times a day at 8：00, 12：00 and 16：00 respectively, for 5 continuous days. Rats in normal control group were given the same treatment as that in the morphinistic group except that saline was instead of morphine. The experiment began at 8：00 on the 6^th day after the symptoms withdrew naturally for 30 minutes. （3） The right sciatic nerve was stimulated by train of electrical impulses as noxious stimuli. The electrical discharges of pain excitation neurons in the caudate nucleus were recorded with glass microelectrode to observe the influences of the intracerebroventricular injection of dopamine on the electrical activities of pain excitation neurons.
RESULTS： All the 52 rats were involved in the analysis of results. （1） Dopamine could enhance the excitabilities of pain excitation neurons in the caudate nucleus of normal rats, the average net-increased value of 22 pain excitation neurons was increased by （131.8±10.3）%, and the latency was shortened by （55.6±6.3）% in comparison with those before injection of dopamine （100%）. （2） Dopamine could decrease the excitabilities of pain excitation neurons in the candate nucleus of the morphinistic rats, the average net-increased value of 17 pain excitation neurons was decreased by （74.8±7.6）%, and the latency was prolonged by （82.1±8.3）% in comparison with those before injection of dopamine （100%）.
CONCLUSION： Dopamine can enhance the excitabilities of pain excitation neurons in the eaudate nucleus of normal rats to the electrical stimulation, manifested by the facilitated pain. Dopamine can inhibit the electrical activities of pain excitation neurons in the caudate nucleus of morphinistic rats, manifested by the analgesic effect.
出处
《中国临床康复》
CAS
CSCD
北大核心
2006年第14期102-104,共3页
Chinese Journal of Clinical Rehabilitation
基金
国家自然科学基金资助项目(30240058)~~
