TABLE 2

Potassium currents recorded from cardiomyocytes isolated from CYP2J2 Tr mice and Wt control mice Current density (picoamperes per picofarad) was calculated by the amplitude of currents divided by the membrane capacitance of individual cardiomyocytes. I_{to, peak} is the maximal peak transient outward K⁺ currents; I_{to,280 ms} is the transient outward K⁺ current measured at the point of _{280 ms}. I_to was elicited by a 300-ms test pulse from a holding potential of -60 to +50 mV every 10 s. I_{K, slow}, a slowly inactivating outward K⁺ current was measured as the maximal current during a 100-ms test pulse from -60 to +50 mV after a 200-ms conditioning pulse from -50 to +40 mV and a 5-ms interval at -50 mV (see the protocol of Figure 3D). I_K1 was measured as the maximal inward currents elicited by 300-ms hyperpolarizing pulses from a holding potential of -40 to -100 mV. All values are mean ± S.E.M. The peak current density data under control conditions and after MS-PPOH and cAMP treatments were reported elsewhere in preliminary form (Xiao, 2007).