Distant intestinal stimulation by cholera toxin in rat in vivo

Cholera toxin (16 microg/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 E2 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 E2 release, indomethacin (10 mg/kg, s.c.), and the 5-HT3 subtype receptor antagonist, granisetron (30 microg/kg i.v.), inhibited the jejunal secretion but had no effect on distant duodenal secretion. However, indomethacin statistically significantly decreased prostaglandin E2 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 E2 in choleraic jejunal secretion but not in distant duodenal secretion.