Figure 6.

 Kinetics of the Cav1 channel subtypes. One‐second square‐step depolarizing pulses were applied at −10 mV every 5 min. (a) Inactivation kinetics. Left, Ca²⁺ current remaining at the end of a 1‐s pulse expressed as a percentage of the peak current (I ₁₀₀₀/I _peak) in WT (black column) and Cav1.3^−/− cells (grey column); middle, percentage of cells whose inactivation kinetics could be well fitted to a single (τ_{inact single}, black columns) or to a double (τ_{inact double}, grey columns) exponential function in WT and Cav1.3^−/−; right, the average τ_{inact single} yielded by the single exponential fitting, and τ_{inact double}, which exhibited two components, a fast component (τ_{inact fast}) and a slow component (τ_{inact slow}), were plotted for WT and Cav1.3^−/− cells (black and grey columns, respectively). (b) Original traces of the Cav1 channel currents recorded in WT and Cav1.3^−/−cells were averaged, superimposed and scaled to the peak WT Cav1 channel current. Number of cells indicated in parentheses. Data were obtained in three paired cultures of WT and Cav1.3^−/− cells, using two mice of each strain.