Yihua Zhong1,2, Jicheng Wang1, Jonathan Beckel3, William C de Groat3, Changfeng Tai1,3,4. 1. Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA. 2. School of Biomedical Engineering, Capital Medical University, Beijing, China. 3. Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA. 4. Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
Abstract
OBJECTIVE: To reveal the possible mechanisms underlying poststimulation block induced by high-frequency biphasic stimulation (HFBS). MATERIALS AND METHODS: A new axonal conduction model is developed for unmyelinated axons. This new model is different from the classical axonal conduction model by including both ion concentrations and membrane ion pumps to allow analysis of axonal responses to long-duration stimulation. Using the new model, the post-HFBS block phenomenon reported in animal studies is simulated and analyzed for a wide range of stimulation frequencies (100 Hz-10 kHz). RESULTS: HFBS can significantly change the Na+ and K+ concentrations inside and outside the axon to produce a post-HFBS block of either short-duration (<500 msec) or long-duration (>3 sec) depending on the duration of HFBS. The short-duration block is due to the fast recovery of the Na+ and K+ concentrations outside the axon in periaxonal space by diffusion of ions into and from the large extracellular space, while the long-duration block is due to the slow restoration of the normal Na+ concentration inside the axon by membrane ion pumps. The 100 Hz HFBS requires the minimal electrical energy to achieve the post-HFBS block, while the 10 kHz stimulation is the least effective frequency requiring high intensity and long duration to achieve the block. CONCLUSION: This study reveals two possible ionic mechanisms underlying post-HFBS block of axonal conduction. Understanding these mechanisms is important for improving clinical applications of HFBS block and for developing new nerve block methods employing HFBS.
OBJECTIVE: To reveal the possible mechanisms underlying poststimulation block induced by high-frequency biphasic stimulation (HFBS). MATERIALS AND METHODS: A new axonal conduction model is developed for unmyelinated axons. This new model is different from the classical axonal conduction model by including both ion concentrations and membrane ion pumps to allow analysis of axonal responses to long-duration stimulation. Using the new model, the post-HFBS block phenomenon reported in animal studies is simulated and analyzed for a wide range of stimulation frequencies (100 Hz-10 kHz). RESULTS: HFBS can significantly change the Na+ and K+ concentrations inside and outside the axon to produce a post-HFBS block of either short-duration (<500 msec) or long-duration (>3 sec) depending on the duration of HFBS. The short-duration block is due to the fast recovery of the Na+ and K+ concentrations outside the axon in periaxonal space by diffusion of ions into and from the large extracellular space, while the long-duration block is due to the slow restoration of the normal Na+ concentration inside the axon by membrane ion pumps. The 100 Hz HFBS requires the minimal electrical energy to achieve the post-HFBS block, while the 10 kHz stimulation is the least effective frequency requiring high intensity and long duration to achieve the block. CONCLUSION: This study reveals two possible ionic mechanisms underlying post-HFBS block of axonal conduction. Understanding these mechanisms is important for improving clinical applications of HFBS block and for developing new nerve block methods employing HFBS.
Authors: Guangning Yang; Zhiying Xiao; Jicheng Wang; Bing Shen; James R Roppolo; William C de Groat; Changfeng Tai Journal: Med Biol Eng Comput Date: 2016-07-01 Impact factor: 2.602
Authors: Jialiang Chen; Yihua Zhong; Jicheng Wang; Bing Shen; Jonathan Beckel; William C de Groat; Changfeng Tai Journal: Neuromodulation Date: 2021-12-18
Authors: Yihua Zhong; Jicheng Wang; Jonathan Beckel; William C de Groat; Changfeng Tai Journal: J Comput Neurosci Date: 2021-11-20 Impact factor: 1.453