5-羟色胺在F344大鼠下丘脑释放及其免疫调节作用

摘要

在F344雄性大鼠腹腔注射血蓝蛋白(KLH),研究T-细胞依赖抗原初始免疫反应对中枢神经系统5-羟色胺(5-HT)代谢的影响.当免疫刺激大鼠4天后,其下丘脑匀浆5-羟色胺水平出现降低,同时应用在体脑微透析技术研究发现清醒大鼠腹腔注射血蓝蛋白4天后,其下丘脑前叶细胞外液的5-羟色胺水平增加.为了评价在免疫反应中大鼠下丘脑5-羟色胺释放效应,本文应用氯苯丙胺(PCA)选择性预先耗竭5-羟色胺释放,并测定这些动物在注射血蓝蛋白后抗体产生情况.结果显示在应用氯苯丙胺预处理的血蓝蛋白免疫动物特异抗体IgM和IgG与未用氯苯丙胺预处理的动物比较均有明显增加(P＜0.01).上述资料表明,对于T-细胞依赖抗原,其初始抗体产生的量是由位于下丘脑5-羟色胺神经终端抑制性递质释放所调节.%To study the effects of a primary immune response to T-cell dependent antigens on central serotonin(5-HT)metabolism,keyhole limpet hemocyanin(KLH)was administered intraperitoneally to F344 male rats. A decrease in hypothalamic 5-HT levels was observed on Day 4 following stimulation of the immune system. In the anterior hypothalamus, a concomitant increase in the basal extracellular 5-HT levels was measured by using in vivo microdialysis in awake rats on Day 4 following KLH administration.Furthermore,to evaluate the consequence of this 5-HT release on the immune response, we selectively denervated serotonin projections with p-chloroan-phetamine (PCA)and measured antibody production in these animals after KLH injection. The production of specific anti-KLH antibodies of IgM and IgG subclasses in the plasma was significantly increased in PCA-treated animals immunized with KLH compared to KLH-injected rats on Days 5,6 and 7 for IgM and Day 6 and 7 for IgG. Our data indicate that the magnitude of the primary antibody resopnses to T-cell antigens such as KLH are subject to tonic inhibitory modulation by serotoninergic nerve terminals located in the anterior hypothalamus.