Investigation into the effect of 5-hydroxytryptamine on fluid transport in the rat small intestine.
1. 5-Hydroxytryptamine (5-HT) has been shown to cause a consistent secretory effect in the rat small intestine only when administered luminally or by close intraarterial infusion. Intraluminal 5-HT-induced secretion is possibly mediated by 5-HT4 receptors. Therefore, it was decided to investigate the effect of 5-HT and selective 5-HT4 receptor agonists (SC 53116 and DAU 6236) on intestinal fluid transport in rat jejunum and ileum. The study also investigated the effect of a selective 5-HT4 receptor antagonist (GR 113808) against the intraluminally administered 5-HT. 2. 5-HT receptor agonists and antagonists were administered intraluminally in pentobarbitone-anesthetized rats. Changes in intestinal fluid transport across the intestinal wall were measured by a single pass technique. 3. Intraluminal 5-HT produced significant antiabsorptive effects is both the jejunum and ileum. The 5-HT-induced responses were blocked by intraluminal administration of the 5-HT4 receptor antagonist GR 113808. The 5-HT4 agonist SC 53116 induced antiabsorptive effects in both regions of the small intestine, but DAU 6236 did not affect the rates of fluid transport. 4. The results indicate that a 5-HT4 receptor has a role in the luminal 5-HT-induced antiabsorptive effect on intestinal fluid transport in the rat.
McLean
P G
PG
School of Pharmaceutical Biology and Pharmacology, Monash University, Parkville, Victoria, Australia.
Coupar
I M
IM
D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D001562:Benzimidazoles / Q000494:pharmacology; D001826:Body Fluids; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007408:Intestinal Absorption / Q000187:drug effects*; D007421:Intestine, Small / Q000187:drug effects* / Q000502:physiology; D008297:Male; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013449:Sulfonamides / Q000494:pharmacology
D001549:Benzamides; D001562:Benzimidazoles; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007211:Indoles; D011758:Pyrroles; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D013449:Sulfonamides; C074331:DAU 6236; C074211:SC 53116; D012701:Serotonin; C082871:GR 113808