摘要
目的 观察褪黑素 (MLT)对大鼠脑内 β 内啡肽 (β Ep)、去甲肾上腺素 (NE)及 5 羟色胺 (5 HT)释放的影响 ,以探讨MLT镇痛作用机制。方法 结合痛阈测定 ,放免测定第三脑室推挽灌流液中 β Ep样免疫活性物质(ir βEp)含量 ;高效液相色谱法测定脑内微透析液中NE和 5 HT的代谢产物。结果 ipMLT 110mg·kg-1可显著增加第三脑室灌流液中ir βEp含量 ,同时显著提高大鼠痛阈 ;但对中脑导水管周围灰质 (PAG)、下丘脑微透析液中 3 甲氧基 4 羟基苯乙二醇、5 羟吲哚乙酸含量无显著影响。结论 MLT可促进脑内 β Ep的释放 ,可能是其镇痛作用的机制之一 ;MLT的镇痛作用与PAG、下丘脑内NE、5 HT的释放可能无关。
AIM In order to explore the mechanism of action of melatonin to induce analgesia, the present study was undertaken to observe the effects of melatonin on the release of β endorphin (β Ep), norepinephrine (NE) and 5 hydroxytryptamine in rat brain. METHODS With the measurement of pain threshold, push pull perfusion technique and radioimmunoassay were used to determine the immunoreactive β Ep content in the perfusate from the third ventricle of rat brain. The contents of 3 methoxy 4 hydroxyphenyl glycol (MHPG) and 5 hydroxyindole acetic acid in the microdialysate from rat brain were measured by techniques of in vivo microdialysis and high performance liquid chromatography with electrochemical detection. RESULTS The immunoreactive β Ep content in the perfusate from the third ventricle of rat brain was increased significantly ( P <0 05) following an intraperitoneal administration of 110 mg·kg -1 of melatonin, with the increase of pain threshold. The MHPG and 5 HIAA contents in the microdialysate from the periaqueductal gray (PAG) or the hypothalamus were not changed after the administration of melatonin. CONCLUSION Melatonin may promote the release of β Ep in brain, which may be one of the mechanisms of the analgesic action of melatonin. The analgesic action of melatonin may not be related to the release of NE and 5 HT in the PAG or the hypothalamus.
出处
《药学学报》
CAS
CSCD
北大核心
2001年第1期5-9,共5页
Acta Pharmaceutica Sinica
基金
福建省自然科学基金!(C96 0 38)
"九五"国家科技攻关项目!(96 -90 6 -11-0 1)
