Figure 9.

Comparison of diclofenac enhancement of the F1489Q mutant current in external solutions containing high and low concentrations of Na⁺. (A) The oocyte expressing the F1489Q mutant channel was held at −120 mV in the ND-96 solution (containing 96 mM Na⁺) or in the ND-22 solution (containing only 22 mM Na⁺, see materials and methods) and stepped to −20 mV for 100 ms to elicit the Na⁺ currents. 1 mM diclofenac significantly enhances the F1489Q mutant current measured in the ND-96 solution, but has only a negligible effect on the current measured in the ND-22 solution. The dotted line indicates the zero current level. (B) The relative peak current in the ND-96 and in the ND-22 solutions is determined by the same way as that in Fig. 5 C. The dashed line indicates the relative peak current of 1. Diclofenac enhancement of the F1489Q mutant current is evidently weaker with the lower concentration of external Na⁺.