大鼠脑内5-羟色胺在应激性溃疡形成中的作用

通过神经化学和神经药理学的方法,在大鼠观察了冷冻加束缚应激性溃疡的形成过程中,脑内5-羟色胺(5-HT)的作用。结果如下:1.在应激过程中,脑内5-HT 及其主要代谢产物5-羟吲哚乙酸(5-HIAA)的含量明显升高,特别是5-HIAA 的含量随着应激时间的延长持续上升,说明5-HT 的代谢加快。2.脑内5-HT 或5-HIAA 含量在应激45min 时与溃疡指数呈明显的负相关,而在应激180min 时则与溃疡指数呈明显的正相关。3.侧脑室注射5-HT或其前体5-羟色氨酸(5-HTP),对应激性溃疡的形成呈双重作用,小剂量时减轻而大剂量时加重溃疡的形成。4.腹腔注射5-HT 合成阻断剂对氯苯丙氨酸(pCPA)可降低大鼠脑内5-HT 和5-HIAA 含量,使应激60min 鼠的溃疡形成加重,而使应激180min 鼠的溃疡形成减轻。以上结果提示,在大鼠的冷冻加束缚应激性溃疡的形成过程中,脑内5-HT 起着一定的作用,它很可能在应激早期减轻而在应激晚期加重溃疡的形成。

THE ROLE OF BRAIN 5-HYDROXYTRYPTAMINE IN THE GENESIS OF STRESS-INDUCED GASTRIC ULCER IN RATS

Experiments were performed to study the role of brain 5-hydroxytryptamine(5-HT)in the pathogenesis of cold and restraint stress-induced gastric ulcer in ratsby neuropharmacological metthods.The results were as follows:(1)The braincontents of 5-HT and its major metabolite,5-hydroxyindoleacetic acid(5-HIAA),weremarkedly increased during the stress and the increase of 5-HIAA was especial-ly significant With the prolongation of the stress,most probably due to increased meta-bolism of 5-HT in the brain.(2)A significant negative correlation between thebrain contents of 5-HT or 5-HIAA and gastric ulcer index was observed after a 45-min period of stress,whereas a significant positive correlation between them wasobserved after a 180-min of stress.(3)A biphasic effect on the stress-induced gas-tric ulceration was observed by intracerebroventricular injection of 5-HT and itsprecursor 5-hydroxytryptophan(5-HTP),i.e.low doses decreased ulcer index,where-as high doses increased it.(4)Intraperitoneal injection of para-chloropheny-lalanin(pCPA),a 5-HT synthesis blocker,while producing a significant reductionin the contents of brain 5-HT and 5-HIAA,increased ulceration induced by 60-minstress but decreased it after 180-min stress.These results suggest that brain 5-HTmight play a role in the pathogenesis of cold and restraint stress-induced gastriculceration and it may have a mitigating effect in the early period and an exacerbat-ing effect in the later period of stress.