【摘要】 目的 :探讨 β 内啡肽 (β endorphin ,β -EP)在褪黑素 (melatonin ,MT)缓解大鼠吗啡戒断反应中的作用。 方法 :建立急性吗啡依赖大鼠及吗啡自然戒断模型 ,用脑室插管进行推挽灌流及侧脑室微量注射 (icv) ,放免测定脑脊液 (CSF)中 β EP的含量。 结果 :(1)icvβ EP可明显抑制吗啡戒断反应 ,并呈量效关系。 (2 )腹腔注射 (ip)MT明显抑制吗啡自然戒断反应。 (3 )吗啡依赖组大鼠CSF中 β EP含量 (3 2 8± 9 8pg ml-1)低于正常组 (5 4 2± 12 5pg ml-1) ;吗啡戒断组大鼠CSF中 β EP含量 (12 4 3± 17 6pg ml-1)明显高于正常组 :给吗啡戒断组大鼠腹腔ipMT后CSF中 β EP含量 (68 3± 13 0pgml-1)亦比吗啡成瘾组和正常组CSF中 β EP含量高 ;正常大鼠经ipMT后CSF中 β EP含量 (75 6± 15 5pg ml-1)也有提高。结论 :(1) β EP可明显抑制吗啡戒断反应 ;(2 )吗啡成瘾可使CSF中 β EP减少 ,而吗啡戒断大鼠CSF中 β EP却有明显增加 ;(3 )MT可抑制吗啡戒断反应 ,这一抑制效应与脑内 β EP的增加有关。更多还原

【Abstract】 Objective:To explore the possible role of β endorp hi n in effect of melatonin on morphine withdrawal symptoms in rats.Method:Acute model of morphine dependent rat was estalished by gradually increasing the dose of morphine through subcutaneous injections.CSF(cerebrospinal fluid)w a s got by push-pull perfusion and intracerebroventricular injection(icv)in a fixe d tuber.Concentration of β endorphin in CSF was determined by radioimmunoassa y (RIA).Results:(1)The symptoms of natural morphine withdrawal were r e lieved significantly by icv β Endorphin with a dose dependent manner.(2)The s y mptoms of natural morphine withdrawal were also relieved by ip melatonin.(3)The CSF β endorphin level was significantly lower in morphine dependent rats than normal control,but that was higher in natural morphine withdrawal rats.That was also much more increased by ip melatonin in the withdrawal rats than in morphine dependent rats or normal control.Conclusion:The withdrawal symptom s could be relieved by icv β endorphin or by ip melatonin in morphine dependetn rats.The mechanism may be partly due to the elevation of endogenous β endorp hin level in brain of rats in withdrawal更多还原