Yu C X, Wu G C, Xu S F, Chen C H
State Key Laboratory of Medical Neurobiology, Department of Neurobiology, Shanghai Medical University, Shanghai 200032, China.
Sheng Li Xue Bao. 2000 Jun;52(3):207-10.
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 beta-endorphin (beta-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 beta-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 beta-Ep in the PAG, which may be one of the mechanisms of the analgesic effect of melatonin.
本研究旨在探讨褪黑素镇痛作用的中枢机制。采用推挽式灌流技术和放射免疫分析法，观察褪黑素给药后大鼠中脑导水管周围灰质（PAG）灌流液中β-内啡肽（β-Ep）和亮氨酸脑啡肽（L-EK）含量的变化。腹腔注射褪黑素（110mg/kg）后30-50分钟，灌流液中β-Ep含量显著增加，而L-EK含量未发生变化。在对PAG进行推挽式灌流期间，采用温水甩尾试验测量痛阈。结果发现，腹腔注射褪黑素（110mg/kg）40分钟后，大鼠痛阈显著提高。结果表明，褪黑素可能促进PAG中β-Ep的释放，这可能是褪黑素镇痛作用的机制之一。
