应激对大鼠摄食量的影响及其机制的探讨

Effects of stress on food intake of rats and possible mechanisms

目的 观察应激因素作用下大鼠摄食量的变化 ,并初步探讨可能涉及的作用机制。方法 将Wistar大鼠按体重随机分为对照组、1周应激组、2周应激组、3周应激组。记录各组大鼠摄食量的变化 ,观察下丘脑 -垂体 -肾上腺轴 (HPA轴 )中各激素水平的改变 ,测定脑组织中促肾上腺皮质激素释放激素 (CRH )和脑肠肽类递质神经降压素 (neurotensin ,NT)的含量 ,以及血浆中NT、胃泌素、乙酰胆碱酯酶 (acetylcholinesterase)的水平。结果 各应激组摄食量明显降低 ,以 2、3周应激组最为明显 ;各应激组HPA轴均处于激活状态 ,3周时趋向适应 ;NT含量在脑和血浆中都呈现一个早期升高晚期回落的过程 ;应激状态使血浆胃泌素明显上升 ,而乙酰胆碱酯酶水平明显下降。结论 应激可导致大鼠摄食量减少 ,其机制可能涉及HPA轴和迷走神经的激活 。

Objective To observe effects of stress on food intake of rats and discuss the related influential factors. Methods Wistar rats were divided into four groups randoml y:control group,one-week,two-week,three-week stress groups.Food intake was deter mined during the experiment.Corticotropin-releasing hormone and neurotensin cont ent in brain were measured.And neurotensin,gastrin,acetylcholinesterase level in plasma were observed.Results Stress reduced food intake in stress groups,espec ially the two-week and three-week stress groups.The hypothalamic-pituitary-adren al(HPA) axis of rats in stress groups was activated and had a tendency to be ada ptive during the third week.Neurotensin content in brain and plasma demonstrated a trend that increased in early stress phase and decreased in late stress phase .Stress caused gastrin level in plasma to increase significantly and acetylcholi nesterase level to decrease evidently.Conclusion Food intake of rats could be reduced during st ress.The mechnisms might include the activated HPA axis,the action of vagus and the regulation of brain-gut peptides such as nemotensin and gastrin.