EFFECTS OF HEAVY METAL IONS ON THE ELECTRICAL PROPERTIES OF MUCOUS EPITHELIAL CELLS IN THE NEWT STOMACH

Abstract

Zinc ion, Cu²⁺ and Cd²⁺ at 10^-4M or lower concentrations caused a marked decrease in the membrane potential of mucous epithelial cells in the isolated newt stomach without appreciable change in the effective membrane resistance and electrical coupling ratio. Cysteine and acetylpenicillamine antagonized the action of these ions. These ions as well as ouabain blocked the hyperpolarization of membrane due to an increase in intracellular Na+^. The effect of the ions on the relationship between external K⁺-concentration and membrane potential was similar to that of ouabain. Discussion is made on the possibility that the ions inhibit active ion transport by combining with a SH-group of the cell mem brane and, thus, bring about a decrease in membrane potential.