Figure 5.
DA modulation of Ih activation. A, Current measurements in control and DA, obtained from stepping from a holding potential of −30 mV to potentials between −40 and −120 mV for 15 s. B, Activation curves for Ih conductances in control, DA, and wash. Statistical differences between treatments at given step voltages were determined using two-way ANOVA and Fisher's PLSD post hoc comparisons. The gray shading indicates “biologically relevant” potentials. C, Activation curves from conductance measurements normalized to the maximal conductances. D, Percentage difference of conductances (DA/control). The gray shading indicates biologically relevant potentials. Conductances in DA were calculated both with the mean reversal potential measured in DA, and with the same reversal potential as in control. E–G, Maximal conductances, voltage of half-activation, and slope factor values determined from first-order Boltzman fits to the individual plots of conductance over voltage. Statistical significance was determined by repeated-measures ANOVA and Fisher's PLSD post hoc comparisons. *p < 0.05; **p < 0.01; ***p < 0.001. Error bars are SEM.