The pharmacological and receptor binding properties of some novel naltrindole (NTI) and naltrexone benzofurane (NTB) derivatives, modified at positions 3, 5, 14 and 17 were studied. Of the N-(17)-methyl NTI-derivatives, the 14-O-methyl derivative was a potent, highly selective d opioid agonist whereas the 5-methyl derivative of the latter was a moderately potent m agonist. Of the N-(17)-methyl NTB derivatives the 3, 14-OH compound was a potent antagonist whereas the 3-O-methyl, 14-OH derivative was a moderately potent mixed agonist/antagonist at the same receptor. The N-methyl, 14-Omethyl NTI derivative (‘morphindole’) had in vivo a potent gastroprotective effect in rats in the ethanol-induced ulcer model.

Keywords: N-methyl naltrindole-derivatives (morphindoles), isolated organs, N-methyl naltrexone-benzofurane, gastroprotective effect