NK1R在焦虑和应激致青少年期小鼠酒依赖发病机理中的作用研究

Adolescent is susceptible to stress and anxiety, and anxiety and stress is closely related to alcohol dependence. But little is known about the mechanism of anxiety and stress in alcohol dependence in adolescents. The SP/NK1R system is a major mediator of stress and anxiety. NK1R antagonist reduce craving of anxious alcohol dependent person. The author proposes that basal high anxiety level can increase vulnerability to alcohol in adolescent mice. Anxiety and stress up-regulate NK1R level in hippocampus, amygdala and striatum of brain. Mice become alcohol dependent. If we use NK1R antagonist it can prevent or weak the effect. NK1R knock-out mice can’t be alcohol dependent. In order to test the assumption mice postnatal 30 days are used in this study. They are divided into two groups by EPM. Protein and mRNA level of NK1R and GABA-A receptor will be measured from four different experiments including basal anxiety, chronic stress, anti-anxiety medication valium and NK1R knock out in adolescent mice.The study is to explore the role of NK1R and GABA-A receptor in stress and anxiety induced alcohol dependence among adolescent mice. It is the first time to explore the interact effect of NK1R and GABA-A receptor in stress and anxiety induced alcohol dependence among adolescent mice. It will be important to elucidate the mechanism of alcohol dependence among adolescent mice and provide scientific evidence to the treatment of alcohol dependence in adolescents.

青少年期对应激和焦虑易感，而焦虑与应激两者与酒依赖关系密切。但焦虑和应激在青少年期酒依赖中的生物学作用机制不清。SP/NK1R是应激和焦虑的主要调节物，NK1R拮抗剂能减少焦虑性酒依赖者的渴求。作者假设基础高焦虑水平导致小鼠对酒的作用易感，加上应激的作用，导致脑内海马、杏仁核、纹状体三个脑区NK1R水平上调，产生了酒依赖，使用NK1R拮抗剂可阻断或弱化该效应，而NK1R基因敲除后的青少年期小鼠则不能形成酒依赖。为此本项目选用出生后30天的小鼠，分别从基础焦虑水平、慢性应激、地西泮抗焦虑及NK1R基因敲除四组不同的实验研究NK1R及GABA-A受体mRNA变化和蛋白变化在焦虑和应激所致青少年期酒依赖中的作用，首次探索NK1R及其与GABA受体的交互作用在焦虑和应激所致酒依赖中的作用。对阐明青少年酒依赖的发病机制有重要的意义，为研究治疗青少年期酒依赖的药物提供科学依据。

青少年期对应激和焦虑易感，而焦虑与应激两者与酒依赖关系密切。但焦虑和应激在青少年期酒依赖中的生物学作用机制尚不清楚。SP/NK1R是应激和焦虑的主要调节物，NK1R与成瘾犒赏作用有关，因此探索NK1R在焦虑和应激所致酒依赖中的作用对阐明青少年酒依赖的发病机制有重要的意义。本项目使用青少年期雄性C57/BL6小鼠来研究NK1R在焦虑和应激所致青少年期小鼠酒依赖形成中的作用。通过高架十字迷宫实验区分小鼠基础焦虑水平后发现，基础焦虑水平不同的青少年期小鼠在酒精条件性位置偏爱（CPP）测试中表现不同，基础焦虑水平低的小鼠表现出更强的酒精偏好，即更高的酒精CPP值，且CPP值与小鼠海马区NK1R表达正向相关。经过慢性高台应激暴露后的小鼠再进行酒精CPP实验，酒精CPP值降低，且海马区NK1R表达亦降低。但小鼠暴露于慢性高台应激并未明显改变小鼠海马区的NK1R表达。在小鼠进行CPP训练过程中给予NK1R拮抗剂可以干预小鼠酒精CPP的形成。由此可见基础焦虑和应激均会影响酒依赖的形成，而酒精偏好程度与NK1R表达相关。此外，间歇性酒精暴露对青少年期小鼠酒依赖的形成有促进作用，避免青少年过早接触酒精对减少酒依赖的发生有重要意义。焦虑和应激对酒依赖形成的机制尚需进一步探索，NK1R与酒依赖的形成可能存在交互作用。