Abstract
Two β-carboline esters, methyl or ethyl β-carboline-3-carboxylate, β-CCM and β-CCE, were found to antagonize the antinociceptive and satiety action of the sulfated octapeptide cholecystokinin (CCK8) which was administered intracisternallyto mice. β-CCM did not affectthe antinociception induced by morphine. The two β-carboline esters weakly inhibited the food intake in mice. However, when they were administered after CCK8 administration, they reversed the CCK8-induced satiety. Since the two β-carboline esters have been previously shown to act as selective cholecystokinin (CCK) receptor antagonists in the isolated guinea-pig gallbladder muscle, they are suggested to antagonize the central action of CCK through acting on the CCK receptor in the central nervous system. The results obtained from the present paper also suggest that benzodiazepine receptor ligands seem in general to act as CCK receptor antagonists as well.
