Intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency biphasic stimulation

• Published in: Journal of neural engineering 2022-07, Vol.19 (4), p.46024
• Main Authors: Zhong, Yihua, Zhang, Xu, Beckel, Jonathan, de Groat, William C, Tai, Changfeng
• Format: Article
• Language: English
• Subjects: Action Potentials - physiology; axon; Axons - physiology; block; conduction; Electric Stimulation - methods; Membrane Potentials; Models, Neurological; Neural Conduction - physiology; simulation; Sodium
• ISSN: 1741-2560; 1741-2552
• DOI: 10.1088/1741-2552/ac81ef

A new axonal conduction model was used to analyze the interaction between intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency (kHz) biphasic stimulation (HFBS). The model includes intracellular and extracellular sodium and potassium concentrations and ion pumps. First, the HFBS (1 kHz, 5.4 mA) was applied for a duration (59.4 s) long enough to produce an axonal conduction block after terminating the stimulation, i.e. a post-stimulation block. Then, the intensity of HFBS was reduced to a lower level for 4 s to determine if the axonal conduction block could be maintained. The block duration was shortened from 1363 ms to 5 ms as the reduced HFBS intensity was increased from 0 mA to 4.1 mA. The block was maintained for the entire tested period (4000 ms) if the reduced intensity was above 4.2 mA. At the low intensity (4.2 mA) the membrane potential oscillation was strong enough to maintain the block and further increased the intracellular sodium concentration. This study indicates a possibility to develop a new nerve block method to reduce the HFBS intensity, which can extend the battery life for an implantable nerve stimulator in clinical applications to block pain of peripheral origin.