[Effects of monocarboxylic acid derivatives on cardiac ventricular CFTR Cl- channels in guinea pig].

Using the whole-cell recording technique, the effects of monocarboxylic acid derivatives on cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-)-channel were examined in guinea pig ventricular myocytes. Anthracene-9-carboxylic acid (9-AC) added to the bath solution further enhanced the outward component of isoproterenol-induced currents in a reversible manner, whereas 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) or diphenylamine-2-carboxylic acid (DPC) induced a biphasic effect on the currents. Either NPPB or DPC first produced a transient increase in the outward component of current before ensuing inhibition. Intracellular NPPB was found to potentiate isoproterenol-activated currents. It is concluded that these monocarboxylic acid derivatives have different binding sites in cardiac ventricular myocytes, which might partially account for the varied effects in blocking anion channels.