Figure 1.

Roscovitine slowed activation of Ca_(V)1.2 channels. (a) Ca_(V)1.2 currents were activated during 25-ms voltage steps to 30 mV. Roscovitine (Rosc; 100 μM) induced a slowing of activation and inhibition compared to currents before (Cntl) and upon recovery from (WO) roscovitine application. (b) The current–voltage (I–V) relationship shows roscovitine-induced inhibition across all current-generating voltages compared to control and washout. (c) The activation–voltage relationship was measured from tail currents and is shown normalized to maximum current to highlight the small changes induced by roscovitine (symbols are same as in b). The smooth lines are fits using a single Boltzmann function with V_1/2=7.9, 6.6 and 9.1 mV, and slope (k)=12.1, 9.9 and 12.9 for control, roscovitine and washout, respectively. (d) Activation τ (τ_Act) was generated from single exponential fits to current activation (after a 0.3-ms delay) in control, 100 μM roscovitine and washout (symbols are same as in b).