Narcotic agonist and antagonist potencies of a homologous series of N-alkyl-norketobemidones measured by the guinea-pig ileum and mouse vas deferens methods.

The narcotic agonist and antagonist potencies of the series of N-alkyl-norketobemidones from norketobemidone to decylnorketo-bemidone have been determined. The values obtained in the electrically stimulated preparations of the guinea-pig ileum and the mouse vas deferens are closely correlated. The agonist potencies observed in the guinea-pig ileum agree well with those found in the mouse hot-plate test (Oh-ishi & May) and those obtained by determining the inhibition of naloxone binding in brain homogenates (Wilson, Rogers, Pert & Snyder). The antagonist potencies in the guinea-pig ileum and, to a lesser extent, those in the mouse vas deferens agree with the values obtained in the morphine-dependent monkey.