Figure 4.

Effects of H-89, calyculin A and isoprenaline on recovery of I_Ca from voltage-dependent inactivation. (a) The inset in the bottom part of the figure shows the double-pulse protocol during which myocytes were depolarised from −40 to 0 mV with a progressively increasing interpulse interval (20 ms increments). The other panels in (a) show representative tracings illustrating the recovery of I_Ca in control conditions and in the presence of calyculin A (1 μmol l⁻¹), isoprenaline (1 μmol l⁻¹) and H-89 (10 μmol l⁻¹). (b) Mean (±s.e.m.) time course of I_Ca recovery fitted with the Boltzmann equation. (c) Mean (±s.e.m.) T_0.5 under control conditions (n=6) and in the presence of calyculin A (n=6), isoprenaline (n=4) and H-89 (n=9). ^*P<0.05.