EFFECT OF ONDANSETRON ON SALMONELLA TYPHIMURIUM-INDUCED NET FLUID ACCUMULATION IN THE PIG JEJUNUM IN-VIVO

Two major pathophysiological mechanisms explaining the diarrhoea induc ed by Salmonella typhimurium have been suggested to be: (a) invasion o f the intestine by the bacteria, and (b) an enterotoxin resembling Vib rio cholerae toxin. Cholera toxin is a potent secretagogue in pig smal l intestine and induces secretion partly by activating 5-hydroxytrypta mine receptors, following release of 5-hydroxytryptamine. Ondansetron is a selective 5-hydroxytryptamine-3 receptor antagonist, which reduce s the cholera toxin-evoked fluid accumulation in pig jejunum. The aim of this study was to investigate the effect of ondansetron on Salmonel la typhimurium-induced fluid accumulation in ligated loops of pig jeju num in vivo. 10(10) colony-forming units of the bacteria was injected into loops and incubated for 8 hr. 200 mg X kg(-1) ondansetron given s ubcutaneously reduced the Salmonella typhimurium-induced fluid accumul ation by about 40%. This result suggests the involvement of 5-hydroxyt ryptamine and 5-hydroxytryptamine-3 receptors in Salmonella typhimuriu m induced diarrhoea. (C) 1997 Elsevier Science Inc.