-β-Carbolines Selectively Antagonize the Cholecystokinin Action in Isolated Guinea-Pig Gallbladder Muscle

[摘要] References(23)Cited-By(3)Two β-carbolines, methyl β-carboline-3-carboxylate (β-CCM) and ethyl β-carboline-3-carboxylate (β-CCE), caused the parallel shift of the doseresponse curve for cholecystokinin (CCK) in isolated guinea-pig gallbladder muscle. The Schild plot regarding the parallel shift in the dose-response curves had a regression line with a slope of 1.03 and a pA2 value of 5.17 for β-CCE, while the method of van Rossum gave a pA2 value of 5.24 for β-CCE and 5.53 for β-CCM. Both the β-carbolines protected CCK receptors in the gallbladder muscle from alkylation by dibenamine, but β-CCM did not protect acetylcholine receptors from dibenamine alkylation. These results suggest that 9-CCM and 3-CCE, so-called inverse agonists of benzodiazepines (BZP), antagonize the CCK action in the gallbladder muscle in a competitive manner, and the antagonism takes place at CCK receptor sites. No spare receptors for CCK were found in the guinea-pig gallbladder muscle.

[学科分类] 药理学