Synchronization Modulation of Na/K Pumps Induced Membrane Potential Hyperpolarization in Both Physiological and Hyperkalemic Conditions

• DOI: 10.1007/s00232-019-00080-7
• Publication Date: 2019-08-13T06:02:46Z
• Authors: Pengfei Liang; Jason Mast; Wei Chen
• Keywords: 0303 health sciences; Ion Transport; Muscle Fibers, Skeletal; Sodium; Membrane Potentials; Mice; 03 medical and health sciences; Dogs; Potassium; Animals; Myocytes, Cardiac; Sodium-Potassium-Exchanging ATPase; Ouabain

The capability of the synchronization modulation (SM) technique in enhancing the function of Na/K pumps has been demonstrated in various cells and tissues, including cardiomyocytes, a monolayer of cultured MDCK kidney cells, peripheral blood vessels, and frog skeletal muscles. This study characterized the membrane potential hyperpolarization induced by SM in both physiological and high [K+]o conditions on single skeletal muscle fibers. The results showed that SM could consistently induce membrane potential hyperpolarization by a few millivolts, and this hyperpolarization was not possible in the presence of ouabain. In contrast, the same electrical pulses but with random frequencies, constant frequencies, or synchronization with backward-modulation could not hyperpolarize the membrane potential. Prolonged field application and higher field intensity enhanced the effects of SM-induced hyperpolarization. Finally, the effect of SM was tested on skeletal muscle fibers incubated in a solution with high external potassium. Results showed that the SM electric field could hyperpolarize the membrane potential even if the external K+ concentration was higher than the normal, which implied the therapeutic effects of the SM electric field on the hyperkalemic situation.