Basolateral membrane ionic conductance in frog skin.

The basolateral membrane resistance of frog skin was determined using standard equivalent circuit analysis. Data obtained with different formal approaches were found to deviate sometimes drastically; however, the data do not permit to identify the origin of this inconsistency nor do they indicate which kind of equivalent circuit calculation yields inappropriate results. Within either formulation, response to experimental perturbation appears to be qualitatively accessible. Using increasing concentrations of amiloride to inhibit transcellular current flow, I/V relationships of the basolateral membrane were obtained which showed pronounced non-linearity with decreasing resistance at decreasing current (and hyperpolarizing membrane). The shape of the I/V relationship was opposite after serosal Ba2+. It is suggested that the potassium channels of the basolateral membrane might show kind of inward or "anomalous" rectification known from other membranes.