New Pharmacologic Aspects of β-Diethyl-Aminoethyl 2,2-Diphenylpentanoate

In a comparison with atropine and structurally related adiphenine using a gross in vivo screen in rats, β-diethyl-aminoethyl 2,2-diphenylpentanoate (SKF 525-A) appeared to act peripherally as a parasympatholytic and/or sympathomimetic. SKF 525-A apparently has some selective activity on the central nervous system (blepharoptosis, hypothermia) indicating a capacity to cross the blood-brain barrier. Drug-receptor interactions were studied on the isolated rat jejunum using furtrethonium as the agonist. SKF 525-A was primarily a noncompetitive antagonist with a competitive component and qualitatively different from the activities of atropine, adiphenine, and papaverine. The respective pA2 and pD'2 values are reported. The SKF 525-A receptor appears composed of the cholinergic receptor plus another spasmogen receptor. SKF 525-A did not inhibit the action of acetylcholinesterase, but was a potent inhibitor of monoamine oxidase at physiological concentrations.