ZAPA, (Z)‐3‐[(aminoiminomethyl)thio]‐2‐propenoic acid hydrochloride, a potent agonist at GABA‐receptors on the Ascaris muscle cell

Abstract

This study is the first report of a compound which is equal in efficacy to γ‐aminobutyric acid (GABA) at the nematode Ascaris muscle GABA‐receptor. The GABA‐receptor at the Ascaris muscle cell which mediates a membrane hyperpolarization and muscle relaxation has eluded classification. The structure‐activity profile of this receptor is not typical of GABAA or GABAB‐receptors. Here we report that the isothiouronium compound ZAPA is as potent as GABA at this receptor. This finding has important implications for the characterization of the Ascaris GABA‐receptor and the design of novel anthelmintics. 1988 British Pharmacological Society