【摘要】 本文采用推挽灌流技术、放射免疫测定法 ,观察褪黑素 (melatonin ,MEL)对大鼠中脑导水管周围灰质(PAG)推挽灌流液中 β 内啡肽 (β Ep)、亮氨酸脑啡肽 (L EK)含量的影响 ,以探讨MEL镇痛效应的中枢机制。结果显示 ,给药组大鼠腹腔注射 (ip)MEL 110mg/kg后 30～ 5 0min ,PAG灌流液中β Ep含量显著增加 ,而L EK含量未见显著变化 ;在推挽灌流同时用 5 0℃热水刺激甩尾法测定痛阈 ,可见ipMEL 110mg/kg后 40min ,大鼠痛阈显著升高。上述结果提示 ,MEL可促进PAG内 β Ep的释放 ,这可能是其发挥镇痛效应的中枢机制之一。更多还原

【Abstract】 The present study was undertaken to explore central mechanisms underlying the analgesic effect of melatonin. Push pull perfusion technique and radioimmunoassay were used to observe the changes in the contents of β endorphin (β Ep) and leucine enkephalin (L EK) in the perfusate from the rat periaqueductal gray (PAG) after administration of melatonin. 30～50 min after an intraperitoneal injection of melatonin (110 mg/kg), the β Ep content in the perfusate was increased significantly, while the L EK content was not changed. Pain threshold was measured using the warm water tail flick test during the push pull perfusion of the PAG. It was found that the rat pain threshold was increased significantly 40 min after the intraperitoneal injection of melatonin (110 mg/kg). The results suggest that melatonin may promote the release of β Ep in the PAG, which may be one of the mechanisms of the analgesic effect of melatonin.更多还原