Homologous N-Alkylnorketobemidones. Correlation of Receptor Binding with Analgesic Potency

For a homologous series of N-alkylnorketobemidones a statistically significant correlation was found between the relative abilities to bind mouse brain homogenate in vitro and their in vivo mouse hot-plate analgesic potencies. The correlation between in vitro binding in the presence of 100 mM sodium and analgesic potency was not as good as that found in the absence of sodium. A statistically significant correlation was also found between their analgesic potencies and their abilities to antagonize electrically induced contractions of the guinea pig ileum.