Figure 8. Activation of I_Cl,ATP by ATPγS is prevented by inhibition of endogenous PKA by Rp-cAMP in mouse ventricular myocytes.

A, time course of changes in whole-cell currents at +80 mV and −80 mV continuously monitored (voltage-clamp protocol is shown on the top) when the cell was consecutively exposed to control solution for 10 min, ATPγS (100 μM) until the changes in current amplitudes reached steady state (≈15 min), and ATPγS + Rp-cAMP (100 μM) until the changes in currents reached steady state. Rp-cAMP eventually abolished the activation of the current even in the presence of ATPγS. B, in the presence of Rp-cAMP (100 μM) ATPγS (100 μM) failed to activate I_Cl,ATP. Same protocol as in A was used to monitor the time course of whole-cell currents.