中文摘要：

目的：探讨侧脑室注射orexin-A对大鼠昼夜摄食的影响。方法：将Wistar大鼠随机分组,采用单剂量侧脑室注射和连续侧脑室注射以及外周注射法,分别于日间和夜间给药,测量大鼠24小时内各阶段的摄食量以及相应生化指标。结果：在光照期间,侧脑室微量注射orexin-A,大鼠4小时内摄食量显著增加（P〈0.05）,且呈剂量依赖关系（P〈0.05）。在夜间初期（18：00）侧脑室注射orexin-A,大鼠食物摄入量无显著差异（P〉0.05）。但在中午12：00给予侧脑室注射orexin-A,注射后4小时内大鼠摄食量显著高于NS对照组（P〈0.05）。连续8日给予orexin-A侧脑室注射,可使注射后日间摄食量显著增加（P〈0.05）,而夜间摄食量显著减少（P〈0.05）,但24小时内总的摄食量不变（P〉0.05）。orexin-A并未改变棕色脂肪组织温度、末梢血糖、血浆瘦素等指标的水平。结论：orexin-A对大鼠摄食的调节具有昼夜节律性。

英文摘要：

Objective： To investigate the effect of the orexin-A on nycterohemeral food intake in rats. Methods： Male wistar rats were randomly assigned to accept a single intracerebroventricul-ar （ICV） injection, continuous ICV injection and perineural injection, dosed in the daytime and dark phase, then measured the food intake of rats during the whole day of various phases and corresponding biochemical indexes. Results： Compared with NS group, inject orexin-A into ICV in the light phase （08：00） dose-dependently increased food intake following the next 4 h in rats （P〈0.05）. Food consumption of rats was unchanged after a single administered ICV with orex- in-A in the early dark times （18：00） （P〉0.05）. Compared with NS group, administered orexin-A into ICV in the light times （12：00） in- creased food consumption following the next 4 h in rats （P〈0.05）. Continuous administered ICV with orexin-A significantly increased the food intakes during the light phase （P〈0.05）, and reduced it during the dark phase （P〈0.05）, but total 24 h food intake was moving （P〉 0.05）. The level of the temperature of brown adipose tissue, peripheral blood glucose, plasma leptin and other indexes were not changed after ICV infusion oforexin-A. Conclusions： The regulation of Orexin-A on food intake in rats was circadian rhythm.