Fig. 3.
The simulated leak conductances and window current components of low-threshold calcium current (IT) and fast transient A-type potassium current (IA) recapitulate the remaining component after elimination of IKir, Ih, and INaP. A: voltage-clamp ramp recordings before (black trace) and after (gray trace) application of 50 μM Ba2+, 300 nM TTX, and 10 μM ZD-7288 to a wild-type TC neuron. B: voltage-clamp ramp recordings before (black trace) and after (gray trace) application of 300 nM TTX and 10 μM ZD-7288 to a Kir2.2 KO TC neuron. C: average values (symbols ± SE) from 10 Kir2.2 KO cells after application of TTX and ZD-7288 (remaining component). Solid lines are simulated I-V plots of the leaks (sodium and potassium), the leaks plus IT, the leaks plus IA, and the leaks plus IT and IA as indicated. Simulations were obtained with the corresponding models (see methods) using ḡKleak = 1.0 × 10−5 S/cm2, ḡNaleak = 3.0 × 10−6 S/cm2, ḡA = 5.5 × 10−3 S/cm2, and pT (maximum permeability) = 5.0 × 10−5 cm/s. D: average voltage-clamp ramp data (±SE) from 24 wild-type TC neurons in the absence of pharmacological agents. Solid line is a voltage-clamp ramp simulation using the model cell with all 7 subthreshold conductances turned on, using the same maximum conductances as in Figs. 1D, 2C, and 3C (default maximum conductances).