Loperamide reduces the intestinal secretion but not the mucosal cAMP accumulation induced by choleratoxin.
The effect of loperamide on net fluid transport and epithelial cAMP accumulation was tested in choleratoxin-exposed ligated colon loops of the rat in vivo. Purified choleratoxin (50 micrograms/ml saline, for 5 h) induced net secretion and doubled cAMP levels in comparison with saline-treated controls. Loperamide (4 mg/kg intragastrically) reduced this secretion by 75%, without diminishing cAMP accumulation; it had no effect on basal fluid transport or cAMP. The data suggest that the opiate analogue interferes with the secretory process at a point beyond the cAMP increase caused by activation of adenylate cyclase.
D000818:Animals; D002772:Cholera Toxin / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D005260:Female; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D008139:Loperamide / Q000494:pharmacology*; D010880:Piperidines / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D010880:Piperidines; D011506:Proteins; D008139:Loperamide; D002772:Cholera Toxin; D000242:Cyclic AMP