Activation of separated Na+ and K+ channels in an excitable model cell: Using stimulating step pre-pulse waveform

Application of constant step voltage in the presence of channel blocker and different extracellular ionic concentration results in activation or inactivation of one or both K⁺ and Na⁺ channel gates in voltage clamp condition. With recording the membrane currents, the kinetic behavior of ionic channel gates are studied. In the present research, the effect of stimulating pre-pulse voltage steps is considered to control the time course of voltage dependent Na⁺ and K⁺ channel activity. Stimulation waveform was designed in order to control the time course of gating and to separate of Na and K channel activity. Then, by applying the stimulus waveform on model and studying the step responses, characteristics and kinetic parameter values were defined. This modeling study has also presented an adequate stimulating signal to separate Na⁺ and K⁺ channel activities with maximum conductance during the stimulation period.