Secretory pathways in Salmonella Typhimurium-induced fluid accumulation in the porcine small intestine

1 Departments of Physiology and Anatomy, Royal Veterinary and Agricultural University, Bülowsvej 13, DK-1870 Frederiksberg C, Denmark 2 Clinical Studies, Royal Veterinary and Agricultural University, Bülowsvej 13, DK-1870 Frederiksberg C, Denmark 3 Veterinary Microbiology, Royal Veterinary and Agricultural University, Bülowsvej 13, DK-1870 Frederiksberg C, Denmark * Corresponding author: Dr M. L. Grøndahl. Received April 23, 1997 Accepted June 18, 1997 The involvement of 5-hydroxytryptamine (5-HT) and 5-HT 3 receptors and prostaglandin E 2 (PGE 2 ) in Salmonella Typhimurium-induced fluid accumulation in the porcine small intestine was investigated. Salmonella Typhimurium (10 8 and 10 10 cfu) and cholera toxin (CT; 20 µg) were instilled for 8 and 11 h in ligated loops in the porcine jejunum and ileum. Fluid accumulation and concentrations of Na + , K + , Cl - , 5-HT and PGE 2 in the fluid accumulated in the loops were measured. The fluid accumulation was also measured when Salmonella Typhimurium (10 10 cfu) and CT (20 µg) were instilled for 8 h in ligated loops in jejunum and ileum in pigs given subcutaneous injections of saline or the 5-HT 3 receptor antagonist ondansetron (200 µg/kg). Salmonella Typhimurium (10 10 cfu) and CT both induced fluid accumulation in jejunum and ileum after 8 and 11 h. Both treatments also induced an increase in luminal release of 5-HT and PGE 2 . The accumulated fluid was iso-osmotic and hyperosmotic in CT- and Salmonella Typhimurium-treated loops, respectively. Ondansetron reduced the Typhimurium-induced fluid accumulation in both jejunum and ileum by c. 40%, while it failed to reduce the response to CT. These results demonstrate that 5-HT and PGE 2 are released and 5-HT 3 receptors activated in the secretory pathway of Typhimurium in the porcine small intestine.