Fig 10. Ultra-long and bistable action potentials in the Qu-Chung [16] model.

(A) Repolarization failure induced by slowing the activation rate (1/γ) of the delayed rectifier potassium current. (B) Repolarization failure induced by negatively shifting the voltage-dependence of L-type calcium current inactivation by Δ mV. (C) Monostable and bistable action potential configurations used in subsequent simulations. The values γ = 4 and Δ = −15 were chosen to produce a robust bistable action potential that does not repolarize in the isolated cell. All other parameters are indentical to [16] except for I_K1,max = 0.3.