Action of Ganglion Blocking Drugs on Choline Acetylase

Abstract

THE first practical hypotensive drugs which acted by causing autonomic ganglionic block were bis-quaternary ammonium salts; recently, substances containing only a single secondary or tertiary amine group have been introduced as hypotensive agents of a similar type. There are, however, differences in the details of the pharmacological actions of the two types of drugs; for example, the mono-amine compounds, mecamylamine and pempidine, are slower in onset of action but more prolonged when compared with the older group (for example, hexamethonium or pentolinium). The bis-quaternary ammonium drugs paralyse ganglia by extracellular competition with acetylcholine for synaptic receptor sites; the differences in action might be explicable if the newer compounds acted in some other way, for example, by inhibition of acetylcholine formation. Their ability to penetrate cell lipid membranes or barriers makes such an intracellular action plausible.