FIG. 3.
DPPX knockdown decreases CA1 input resistance. A: subthreshold voltage transients generated in response to 900-ms current injections for siDPPX (red traces) and control neurons (black traces) recorded 2 days after infection. Current injections were −200, −150, −100, −50, and +50 pA. Smaller voltage deflections are seen in the siDPPX cell for all injections. B: current-voltage relationship for the peak (left) and steady-state (∼900 ms, right) voltages for negative control siRNA-expressing cells (black symbols) and siDPPX-expressing cells (red symbols). Lines are linear regression fits of the data. Both peak and steady-state responses are reduced compared with control in siDPPX-expressing neurons after 2 days postinfection (day 2–3, red circles) but not 1 day postinfection (day 1, red triangles). C: plot showing the “sag” (difference between peak and steady-state voltages) for each current injection. On hyperpolarization, less sag is seen for siDPPX on after day 2 indicating less Ih activation. D: sag is plotted against the peak voltage. This relationship did not differ between experimental groups indicating that the changes in Ih seen in C are due to siDPPX-dependent reduction in the peak voltage reached early during the current injection. Error bars represent SE.