Changes to erythrocyte membrane cation permeability induced by a bacterial toxin

Vibrio parahaemolyticus secretes an exotoxin prepared as Kanagawa haemolysin (KH) which causes marked alterations to the function of epithelial, cardiac and other cell types, but whose cellular mode of action is poorly understood. Using human red cells as a model system with radiotracer flux techniques, we have shown that KH (1) markedly elevated the basal leak to K⁺, (2) raised Ca²⁺ influx, and as a consequence of this, (3) stimulated the Ca²⁺-activated K⁺ channel. These results suggest that an important deleterious effect of this toxin is to elevate cation permeability, which will have both direct and indirect actions on the behaviour of a variety of cell typesin vivo.