Difference between the effect of acute and chronic surgical vagotomy on the cytoprotective action of atropine against indomethacin-induced mucosal lesions on the gastrointestinal tract in rats

The cytoprotective effect of a small dose of atropine was proved against th e indomethacin (IND)-caused gastrointestinal (GI) mucosal damage. This prot ective effect of atropine disappeared in the acute phase of surgical vagoto my (ASV) on the vagally-innervated parts of GI tract. The aims of our obser vations were: 1) to examine the effect of chronic surgical vagotomy (CSV) o n the cytoprotective action of atropine in the GI tract; and 2) to compare the effects of ASV and CSV on the GI cytoprotection caused by atropine agai nst IND-induced mucosal damage and vascular permeability in rats. The IND w as given s.c. 24 h prior to the killing of the animals in a dose of 20 mg.k g(-1). Bilateral surgical vagotomy or sham operation were carried out 24 h (ASV) or 14 d (CSV) before IND-application. Atropine was given i.p. every 5 h after IND-treatment in a dose of 0.1 mg.kg(-1). The number of macroscopi cal mucosal ulcerations was noted and its severity was calculated by semiqu antitative scale in the stomach, small intestine and three equal parts of c olon. Vascular permeability was measured by Evans-blue leakage into the muc osal tissue. It has been found that: 1) Tte small dose of atropine signific antly decreased the IND-induced mucosal damage and vascular permeability on the stomach, small intestine and the vascular permeability on the proximal colon; 2) the small dose of atropine did not cause any changes in the appe arance of IND-induced mucosal lesions and in Evans blue concentration in th e mucosa after ASV, but it significantly decreased the IND-caused mucosal d amage and Evans blue concentration in the mucosa of stomach, small intestin e and proximal colon after CSV; 3) the IND-induced mucosal damage and vascu lar permeability treated with atropine (given in cytoprotective dose) were significantly smaller after CSV than that after ASV on the stomach, small i ntestine and proximal colon. It has been concluded that the intact vagal ne rve has an essential role in the appearance of cytoprotective mechanisms of atropine in GI tract. (C) 1999 Elsevier Science Ltd. Published by Editions scientifiques et medicales Elsevier SAS.