Distant intestinal stimulation by cholera toxin in rat in vivo

Cholera toxin (16 mu g/rat) locally administered in the jejunum of anesthetized rats stimulated jejunal secretion and also distant duodenal secretion, as determined with the ligated loop technique. The release of prostaglandin E-2 in both jejunal and duodenal secretions and in plasma was increased by cholera toxin, while the release of 5-hydroxytryptamine (5-HT) was unchanged in the early phase of secretion (2 h). The inhibitor of prostaglandin E-2 release, indomethacin (10 mg/kg, s.c.), and the 5-HT3 subtype receptor antagonist, granisetron (30 mu g/kg i.v.), inhibited the jejunal secretion but had no effect on distant duodenal secretion. However, indomethacin statistically significantly decreased prostaglandin E-2 release in both jejunal and duodenal secretions as well as in plasma. The vasoactive intestinal peptide antagonist (VIP-(6-28), 1.2 nmol/100 g h) did not modify jejunal and duodenal secretions. Our study confirmed the local involvement of 5-HT and prostaglandin E-2 in choleraic jejunal secretion but not in distant duodenal secretion. (C) 1999 Elsevier Science B.V. All rights reserved.