Potent, selective blocker of the volume-sensitive anion channel (VSAC) in rat pancreatic β-cells (IC50 ~ 2 μM) and ICl,swell in various cardiovascular tissues (IC50 = 4.1 μM in CPAE cells); blockade is voltage-independent. Displays minimal inhibition of other Cl- and K+ currents (< 10% inhibition at 10 μM). Inhibits glucose-stimulated insulin secretion in intact β-cells via VSAC inhibition and indirect KATP channel activation. Reverses cell swelling-induced action potential duration shortening in atrial myocytes and inhibits astroglial swelling in vitro.