Synchronization of Na/K pump molecules by a train of squared pulses

Abstract

We experimentally studied the Na/K pump currents evoked by a train of squared pulses whose pulse-duration is about the time course of Na-extrusion at physiological conditions. The magnitude of the measured pump current can be as much as three-fold of that induced by the traditional single pulse measurement. The increase in the pump current is directly dependent on the number of pre-pulses. The larger the number of the pre-pulses is, the higher the current magnitude can be obtained. At a particular number of pre-pulses, the pump current becomes saturated. These results suggest that a large number of pre-pulses may synchronize the pump molecules to work at the same pace. As a result, the pump molecules may extrude Na ions at the same time corresponding to the stimulation pulses, and pump in K ions at the same time during the pulse intervals. Therefore, the measured pump current is three-fold of that measured by a single pulse where the outward and inward pump currents are canceled each other.

Synchronization of Ion Exchangers by an Oscillating Electric Field: Theory

“…This result along with the results of our systemic experimental studies [20][21][22] demonstrates synchronization of the Na/K pumps through the application of a well-designed oscillating electric field. Each pump molecule extrudes three Na ions out of the cell and pumps in two K ions in each cycle, resulting in one net charge outflux.…”

Reducing ischemic kidney injury through application of a synchronization modulation electric field to maintain Na + /K + -ATPase functions

“…We chose to focus on the pumping cycle, wherein the outward Na + and inward K + transports result in alternating opposite pump currents. Thus, application of an oscillating electric field might be able to activate the pump functions by alternately activating two ion transport steps (29)(30)(31)(32). However, there are millions of pump molecules in each cell, running independently with random paces and different pump rates, making it impossible to use one electric field to control all the pump molecules.…”

“…However, there are millions of pump molecules in each cell, running independently with random paces and different pump rates, making it impossible to use one electric field to control all the pump molecules. We previously addressed this limitation by developing a technique that applies an oscillating electric field to first synchronize the pump molecules and then modulate their pumping rates (29)(30)(31)(32)(33)(34)(35). We dubbed this technique as the synchronization modulation electric field (SMEF).…”

“…The first generation of this technique (1 st gen-SMEF) (36) synchronized the two ion transport steps in the pumping cycle and controlled the pump rates (29)(30)(31)(32). We subsequently improved this technique so that the Na/K pumps could be synchronized down to the individual steps of the pump cycle, resulting in the real-time semisingle pump current (2 nd gen-SMEF) (37).…”

Distribution of the Na/K Pumps’ Turnover Rates As a Function of Membrane Potential, Temperature, and Ion Concentration Gradients and Effect of Fluctuations

“…Consequently, the pump currents show only outward currents due to the cancellation of the inward K and outward Na currents from different pumps. Recently, we developed a technique of synchronization modulation to electrically activate the pumping rate of Na/K pumps [1][2][3][4][5] on amphibian skeletal muscle fibers and mammalian cardiomyocytes. The first step in this technique is to use an oscillating electric field to synchronize the pump molecules to work at the same pumping rate and phase.…”