FIG. 2.

Effects of siDPPX on A-type K⁺-channel voltage-dependent properties in CA1 pyramidal neurons. A: efficiency of endogenous DPPX knockdown by siDPPX in hippocampal neurons. Immunoblots of hippocampal neurons (DIV 14), ∼50% infected by the attenuated Sindbis virus-expressing siDPPX or negative control siRNA. The blots show that endogenous DPPX protein is substantially reduced by siDPPX within 2 days after infection, consistent with heterologous CHO cell data. β-actin is shown as control. B: representative traces from outside-out patches from siDPPX (red traces) and Neg. Ctrl. siRNA (black traces)-expressing neurons, scaled to the same peak amplitude for comparison. Voltage steps are depicted above. C: conductance voltage (G/G_max) and steady-state inactivation (I/I_max) curves for A-type currents recorded from somatic outside-out patches in siDPPX (days ^2,3, red circles and fits) and negative control siRNA (black circles and fits)-infected CA1 neurons. There was a rightward shift and significant change in slope for the steady-state activation curve. A rightward shift was also seen in the steady-state inactivation curve with siDPPX with no change in slope. Inset: traces are from whole cell recordings for a step from −120 to −60 mV. Neurons expressing siDPPX have larger currents at −60 mV than negative control siRNA-expressing neurons, consistent with the change in activation curve slope and inactivation curve shift. Subtraction artifacts are clipped for presentation. Scale bars: 50 pA, 100 ms. Error bars represent SE.