The pharmacological profile of BAM 18.

The opioid receptor selectivity of BAM 18 was determined by radioligand binding and peripheral tissue bioassay. Using selective radioligand binding conditions, BAM 18 bound to the mu opioid receptor with an affinity twice that of the K receptor and over 10 times that of the delta opioid receptor (Ki = 0.29, 0.84 and 3.9 nM, respectively). Ke values for naloxone antagonism of BAM 18 activity in the electrically stimulated guinea pig ileum and the mouse vas deferens were 4.3 and 9.9 nM respectively. The pharmacological profile of BAM 18 was similar to that of metorphamide.