Antimuscarinic effects of chloroquine in rat pancreatic acini.
Chloroquine inhibited carbachol-induced amylase release in a dose-dependent fashion in rat pancreatic acini; cholecystokinin- and bombesin-induced secretory responses were almost unchanged by the antimalarial drug. The inhibition of carbachol-induced amylase release by chloroquine was competitive in nature with a Ki of 11.7 microM. Chloroquine also inhibited [3H]N-methylscopolamine binding to acinar muscarinic receptors. The IC50 for chloroquine inhibition of [3H]N-methylscopolamine binding was lower than that for carbachol or the other antimalarial drugs, quinine and quinidine. These results demonstrate that chloroquine is a muscarinic receptor antagonist in the exocrine pancreas.
D000681:Amylases / Q000378:metabolism; D000818:Animals; D002217:Carbachol / Q000037:antagonists & inhibitors; D002738:Chloroquine / Q000494:pharmacology*; D066298:In Vitro Techniques; D019832:N-Methylscopolamine; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000378:metabolism; D012602:Scopolamine Derivatives / Q000378:metabolism
D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; D002738:Chloroquine; D002217:Carbachol; D000681:Amylases; D019832:N-Methylscopolamine