Figure 4. Effect of DHA on the voltage dependence of inactivation in adult rat ventricular myocytes.

A, sodium currents were evoked by voltage steps to −30 mV from various holding potentials, as depicted (upper panel). Plotted below are currents evoked at −130, −120, −110, −100, −90, −80, −70, −60 and −50 mV, shown superimposed. B, the peak current amplitude is shown plotted against the holding potential. Points represent typical control data (^) or in the presence of 25 μM DHA (•). The continuous line shows the least squares best fit of eqn (2) for control or DHA. The parameters for the best fit in each case were: control, I_max = −746 pA, V′ = −75.2 mV and k = 5.28 mV⁻¹; and in the presence of 25 μM DHA, I_max = −320 pA, V′ = −99.9 mV and k = 6.60 mV⁻¹. The dashed line shows the data points for DHA scaled to the same maximum as the control data.