Plots of the time course of changes in currents and ion concentrations in the computer simulation following addition of 8 mmol of K ⁺ to the extracellular compartment at time 0. The net inward K⁺ current in the first 10 min is off scale for WT and all three forms of periodic paralysis. (A) Vm. (B) Net Na⁺ current. (C) Net K⁺ current. (D) Intracellular Na⁺ concentration. (E) Extracellular K⁺ concentration. (F) Na/K ATPase current.