[Demonstration of the inhibitory effect of ethacrynic acid on permeability to chlorine].

Ethacrynic acid specifically inhibits chloride permeability in Ox erythrocyte. The I50 is 7 x 10(-6) M. The inhibitory effect is instantaneous and completely reversed by washing the cells with a Ringer solution. Dihydroethacrynic acid, a derivative that lacks the ability to combine with SH groups, also inhibits chloride permeability and the characteristics of inhibition are strictly identical. It is a proof that ethacrytic acid does not act by its reactivity with thiol groups.