Abstract
In dogs under Na pentobarbital anesthesia 5 mg./kg. of 933F will prevent 10 mg./kg. of Dibenamine (dibenzyl-beta-chlorethylamine) from blocking the pressor action of epinephrine. It is proposed that 933F combines reversibly with the same cell receptor that Dibenamine combines with irreversibly when the latter blocks the pressor action of epinephrine.