Synchronization of Na/K pump molecules by a train of squared pulses.
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.
Chen
Wei
W
Center for Cellular and Molecular Biophysics, Department of Physics, University of South Florida, 4020 E. Fowler Ave., Tampa, FL 33620, USA. wchen@cas.usf.edu
Zhang
Zhong Sheng
ZS
D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D004558:Electric Stimulation; D017136:Ion Transport / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D011894:Rana pipiens; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013997:Time Factors
D000254:Sodium-Potassium-Exchanging ATPase