In vitro studies with (imidazolinyl-2)-2-benzodioxane-1-4 ((+/-)-170 150), a new potent alpha 2-adrenoceptor blocking agent.

In rat vas deferens, (+/-)-170 150 proved to be an alpha 2-adrenoceptor blocking agent with a high alpha 2/alpha 1 selectivity ratio. In rat cerebrocortical membranes, (+/-)-170 150 was seven times more potent than yohimbine for inhibiting specific [3H]clonidine binding. However, (+/-)-170 150 appeared to be 3.5 times less selective for alpha 2-adrenoceptors sites than yohimbine. These results indicate that (+/-)-170 150 is a potent preferential alpha 2-adrenoceptor blocking agent, as had been shown by in vivo experiments.