The key-role of vagal nerve and adrenals in the cytoprotection and generalgastric mucosal integrity

Background: Our laboratory group observed earlier that the gastric mucosal cytoprotective effect of prostacyclin (PGI(2)) disappeared after surgical v agotomy in rats. Similarly to this, the beta-carotene induced gastric cytop rotection disappeared in adrenalectomized rats too. Aims: In these studies we aimed to investigate the possible role of vagal nerve and adrenals in th e development of gastric mucosal lesions induced by exogenously administere d chemicals (ethanol, HCl, NaOH, NaCl and indomethacin), and on the effects of cytoprotective and antisecretory drugs (atropine, cimetidine), and scav engers (vitamin A and beta -carotene). Methods: The observations were carri ed out in fasted CFY strain rats. The gastric mucosal lesions were produced by intragastric (i.g.) administration of narcotising agents (96% ethanol; 0.6 M HCl; 0.2 M NaOH; 25% NaCl) or subcutaneously (s.c.) administered indo methacin (20 mg/kg) in intact, surgically bilaterally vagatomized, and adre nalectomized rats without or with glucocorticoid supplementation (Oradexon, 0.6 mg/kg given i.m. for 1 week). The gastric mucosal protective effect of antisecretory doses of atropine (0.1-0.5-1.0 mg/kg i.g.) and cimetidine (1 0-25-50 mg/kg i.g.), and vitamin A and P-carotene (0.01-0.1-1.0-10 mg/kg i. g.) was studied. The number and severity of mucosal gastric lesions was num erically or semiquantitatively measured. In other series of observations th e gastric acid secretion and mucosal damage were studied in 24 h pylorus-li gated rats without and with acute bilateral surgical vagotomy. Results: It was found that: (1) the chemical-induced gastric mucosal damage was enhance d in vagotomized and adrenalectomized rats, meanwhile the endogenous secret ion of gastric acid, and the development of mucosal damage can be prevented by surgical vagotomy; (2) the gastric cyto- and general protection produce d by the drugs and scavengers disappeared in vagotomized and adrenalectomiz ed rats; (3) the gastric mucosal protective effects of drugs and of scaveng ers returned after sufficient glucocorticoid supplementation of the rats. C onclusion: It has been concluded that the intact vagal nerve and adrenals h ave a key role in the gastric mucosal integrity, and in drugs- and scavenge rs-induced gastric cyto- and general mucosal protection. (C) 2001 Elsevier Science Ltd. All rights reserved.