SOME STRUCTURAL REQUIREMENTS OF DRUGS THAT STIMULATE THE PULMONARY ARTERY REFLEXOGENIC ZONE

¹ Department of Pharmacology, School of Medicine, UCLA Center for Health Sciences, Los Angeles, California

The sensory stimulating properties of a heterogeneous group of nicotinic and muscarinic drugs on the reflexogenic area in the region of the pulmonary artery bifurcation have been studied. Reflexogenic potency was assayed in the lightly a-chloralose anesthetized cat against lobeline utilizing the reflex hypotensive response. It was found that not all drugs that stimulate the ganglia, and only a few typically muscarinic drugs, have reflexogenic potency. The following were the most active compounds in decreasing order of potency-lobeline, acetylcholine, nicotine, choline phenyl ether, DMPP, metanicotine and 2 ,4-dimethylphenacyl tetramethylammonium. Tetramethylammonium and derivatives with a purely hydrocarbon side chain were inactive. Carbachol and mecholyl showed marked tachyphylaxis.