Figure 10.

 Contribution of Cav1 channel subtypes to pacemaking activity. (a–b) In a different set of experiments performed under the current‐clamp configuration, the spontaneous oscillatory activity resistant to TTX, obtained in half the cells treated with this toxin, was reversibly abolished by 300 nM nifedipine in WT (a) or Cav1.3^−/− cells (b). In the other half of the cells, reversible blockade of spontaneous action potentials by 2 μM TTX in WT (c) or Cav1.3^−/− (d) cells was achieved. Data were obtained in two paired cultures of WT and Cav1.3^−/− cells using two mice of each strain.