TABLE 3

Effects of mutations that change the interaction of corticosterone with rOCT1 on the affinity of TBuA⁺ from extracellular

Wild-type rOCT1 or rOCT1 mutants were expressed in oocytes. Inhibition of currents induced by superfusion with 0.2 mM or 2 mM TEA⁺ by extracellular TBuA⁺ was measured as in Fig. 2. The Hill equation was fitted to inhibition curves of individual oocytes and IC₅₀ values were calculated. The data are presented and the K_i values were calculated as in Table 1. The ratios between the mean IC₅₀ values measured with 2 mM TEA⁺ and 0.2 mM TEA⁺ [f_{(part.compet.)}] were used to calculate the K_i values from the IC₅₀ value obtained with 0.2 mM TEA⁺.