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褪黑素对吗啡戒断小鼠下丘脑弓状核和中脑导水管周围灰质中#beta#--内啡肽含量的影响

魏义明, 许盈, 俞昌喜

福建医科大学药理学系.福建,福州 350004

摘要

该文在观察腹腔注射褪黑素(melatonin,MEL)拮抗吗啡依赖小鼠纳洛酮催促戒断反应的同时,采用放射免疫分析法、免疫组织化学法,结合计算机图像处理技术,测定其对小鼠中脑导水管周围灰质(periaqueductal grey,PAG)、下丘脑弓状核(hypothalamic arcuate nucleus,Arc)中#beta#--内啡肽(#beta#--endorphin,#beta#--EP)含量的影响。结果表明,MEL(80 mg/Kg体重)显著抑制吗啡依赖小鼠戒断反应({sl P}<0.05)的同时,可显著增加其中脑PAG中#beta#--EP含量({sl P}<0.05),减弱Arc中#beta#--EP样免疫阳性反应强度({sl P}<0.05)。上述结果提示,MEL可提高吗啡戒断小鼠中脑PAG中#beta#--EP含量,降低Arc中#beta#--EP含量。

关键词： 褪黑素; 吗啡依赖; 戒断反应; 下丘脑弓状核; 中脑导水管周围灰质; #beta#-内啡肽

Effect of melatonin on the content of #beta#--endorphin in the hypothalamic arcuate nucleus and periaqueductal grey of midbrain in morphine withdrawal mice

Wei Yiming, Xu Ying, Yu Changxi

Department of Pharmacology,Fujian Medical University.Fuzhou 350004,Fujian

Abstract

The present study was undertaken to investigate the effect of melatonin on the level of #beta#-endorphin (#beta#-EP) in the arcuate nucleus hypothalamus (Arc) and periaqueductal grey (PAG) of midbrain in mice with morphine abstinence. Male Kunming strain mice were injected subcutaneously (s.c.) with an increasing dose of morphine continuously for 8 d to establish dependence model. Withdrawal response was induced by naloxon (3 mg/kg, s.c.). The potency of withdrawal response was evaluated according to the jumping times and body weight loss. Ninty minutes prior to the precipitation of naloxone, 80 mg/kg of melatonin (MEL) was injected intraperitoneally (i.p.) to observe its antagonistic effect on the withdrawal response of morphine-dependent mice. After behavioral observation, radioimmunoassay was used to determine the content of #beta#-EP in the PAG of midbrain, and immunohistochemical assay was used to observe the intensity of #beta#-EP-like immunoreactivity in the Arc in mice. It was shown that melatonin (i.p., 80 mg/kg) inhibited the naloxone-precipitated withdrawal responses in mice significantly (P<0.05). In the meantime, melatonin increased the content of #beta#-EP in the PAG of midbrain significantly (P<0.05) and attenuated the intensity of #beta#-EP-like immunoreactivity in the Arc in mice (P<0.05). The results suggest that melatonin increases the level of #beta#-EP in the PAG of midbrain, decrease the level of #beta#-EP in the Arc in mice with morphine abstinence.

Key words: Melatonin;morphine dependence;withdrawal response;Hypothalamic arcuate nucleus;periaqueductal grey of midbrain;#beta#-endorphin

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引用本文：

魏义明, 许盈, 俞昌喜. 褪黑素对吗啡戒断小鼠下丘脑弓状核和中脑导水管周围灰质中#beta#--内啡肽含量的影响[J]. 生理学报 2007; 59 (6): 765-769.

Wei Yiming, Xu Ying, Yu Changxi. Effect of melatonin on the content of #beta#--endorphin in the hypothalamic arcuate nucleus and periaqueductal grey of midbrain in morphine withdrawal mice. Acta Physiol Sin 2007; 59 (6): 765-769 (in Chinese with English abstract).