Intracellular calcium modulates basolateral K+-permeability in frog skin epithelium

Cytosolic calcium ([Ca²⁺]_i) has been suggested as a key modulator in the regulation of active sodium transport across electrically tight (high resistance) epithelia. In this study we investigated the effects of calcium on cellular electrophysiological parameters in a classical model tissue, the frog skin. [Ca²⁺]_i was measured with fura-2 in an epifluorescence microscope setup. An inhibition of basolateral potassium permeability was observed when cytosolic calcium was increased. This inhibition was reversible upon removal of calcium from the serosal solution.