Figure 6. Sr²⁺ blocks I_K(IR) in a voltage-dependent manner.

A, I_K(IR) traces during strong hyperpolarizing pulses (−180 to +20 mV) from a holding potential of −60 mV from a HCEC perfused with standard external solution. B, current traces from the same cell in the presence of 5 mm Sr²⁺. Both the transient and steady-state components of the inward current were blocked. C, current-voltage plot for the peak current (▪) and the current at the end of the pulse (•) in standard bath solution, and the peak current (□) and the steady-state current (○) in 5 mm Sr²⁺.