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Chen J, Zhong Y, Wang J, Shen B, Beckel J, de Groat WC, Tai C. Temperature Effect on Nerve Conduction Block Induced by High-Frequency (kHz) Biphasic Stimulation. Neuromodulation 2023; 26:607-613. [PMID: 35088749 PMCID: PMC9206037 DOI: 10.1016/j.neurom.2021.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/05/2021] [Accepted: 10/12/2021] [Indexed: 11/17/2022]
Abstract
OBJECTIVES This study aims to determine temperature effect on nerve conduction block induced by high-frequency (kHz) biphasic stimulation (HFBS). MATERIALS AND METHODS Frog sciatic nerve-muscle preparation was immersed in Ringer's solution at a temperature of 15 or 20 °C. To induce muscle contractions, a bipolar cuff electrode delivered low-frequency (0.25 Hz) stimulation to the nerve. To induce nerve block, a tripolar cuff electrode was placed distal to the bipolar cuff electrode to deliver HFBS (2 or 10 kHz). A bipolar hook electrode distal to the blocking electrode was used to confirm that the nerve block occurred locally at the site of HFBS. A thread tied onto the foot was attached to a force transducer to measure the muscle contraction force. RESULTS At 15 °C, both 2- and 10-kHz HFBSs elicited an initial transient muscle contraction and then produced nerve block during the stimulation (ie, acute block), with the 10 kHz having a significantly (p < 0.001) higher acute block threshold (5.9 ± 0.8 mA peak amplitude) than the 2 kHz (1.9 ± 0.3 mA). When the temperature was increased to 20 °C, the acute block threshold for the 10-kHz HFBS was significantly (p < 0.0001) decreased from 5.2 ± 0.3 to 4.4 ± 0.2 mA, whereas the 2-kHz HFBS induced a tonic muscle contraction during the stimulation but elicited nerve block after terminating the 2-kHz HFBS (ie, poststimulation block) with an increased block duration at a higher stimulation intensity. CONCLUSION Temperature has an important influence on HFBS-induced nerve block. The blocking mechanisms underlying acute and poststimulation nerve blocks are likely to be very different.
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Affiliation(s)
- Jialiang Chen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Urology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yihua Zhong
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bing Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Beckel
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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Zhong Y, Zhang X, Beckel J, de Groat WC, Tai C. Intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency biphasic stimulation. J Neural Eng 2022; 19. [PMID: 35850095 PMCID: PMC9355690 DOI: 10.1088/1741-2552/ac81ef] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/18/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE 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). APPROACH 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 seconds) 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 seconds to determine if the axonal conduction block could be maintained. MAIN RESULTS 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 disrupted the post-stimulation block caused by the increased intracellular sodium concentration, while at the high intensity (>4.2 mA) the membrane potential oscillation was strong enough to maintain the block and further increased the intracellular sodium concentration. SIGNIFICANCE 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.
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Affiliation(s)
- Yihua Zhong
- University of Pittsburgh, Department of Urology, 700 Kaufmann Building, Pittsburgh, Pennsylvania, 15261, UNITED STATES
| | - Xu Zhang
- Capital Medical University, School of Biomedical Engineering and Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, China, Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University,100069, Beijing, China, Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Capital Medical University, Beijing 100069, China, Beijing, 100054, CHINA
| | - Jonathan Beckel
- University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, Pittsburgh, Pennsylvania, 15261, UNITED STATES
| | - William C de Groat
- University of Pittsburgh School of Medicine, 4200 Fifth Ave, Pittsburgh,, Pittsburgh, Pennsylvania, 15261, UNITED STATES
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA 15213, USA, Pittsburgh, Pennsylvania, 15261, UNITED STATES
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Tarotin I, Mastitskaya S, Ravagli E, Perkins JD, Holder D, Aristovich K. Overcoming temporal dispersion for measurement of activity-related impedance changes in unmyelinated nerves. J Neural Eng 2022; 19. [PMID: 35413701 DOI: 10.1088/1741-2552/ac669a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 04/11/2022] [Indexed: 11/11/2022]
Abstract
Objective.Fast neural electrical impedance tomography is an imaging technique that has been successful in visualising electrically evoked activity of myelinated fibres in peripheral nerves by measurement of the impedance changes (dZ) accompanying excitation. However, imaging of unmyelinated fibres is challenging due to temporal dispersion (TP) which occurs due to variability in conduction velocities of the fibres and leads to a decrease of the signal below the noise with distance from the stimulus. To overcome TP and allow electrical impedance tomography imaging in unmyelinated nerves, a new experimental and signal processing paradigm is required allowing dZ measurement further from the site of stimulation than compound neural activity is visible. The development of such a paradigm was the main objective of this study.Approach.A finite element-based statistical model of TP in porcine subdiaphragmatic nerve was developed and experimentally validatedex-vivo. Two paradigms for nerve stimulation and processing of the resulting data-continuous stimulation and trains of stimuli, were implemented; the optimal paradigm for recording dispersed dZ in unmyelinated nerves was determined.Main results.While continuous stimulation and coherent spikes averaging led to higher signal-to-noise ratios (SNRs) at close distances from the stimulus, stimulation by trains was more consistent across distances and allowed dZ measurement at up to 15 cm from the stimulus (SNR = 1.8 ± 0.8) if averaged for 30 min.Significance.The study develops a method that for the first time allows measurement of dZ in unmyelinated nerves in simulation and experiment, at the distances where compound action potentials are fully dispersed.
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Affiliation(s)
- Ilya Tarotin
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Svetlana Mastitskaya
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Enrico Ravagli
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Justin D Perkins
- Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, Hatfield, United Kingdom
| | - David Holder
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Kirill Aristovich
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom
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Zhong Y, Wang J, Beckel J, de Groat WC, Tai C. High-frequency stimulation induces axonal conduction block without generating initial action potentials. J Comput Neurosci 2021; 50:203-215. [PMID: 34800252 PMCID: PMC9035068 DOI: 10.1007/s10827-021-00806-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/05/2021] [Accepted: 11/17/2021] [Indexed: 10/19/2022]
Abstract
The purpose of this modeling study is to develop a novel method to block nerve conduction by high frequency biphasic stimulation (HFBS) without generating initial action potentials. An axonal conduction model including both ion concentrations and membrane ion pumps is used to analyze the axonal response to 1 kHz HFBS. The intensity of HFBS is increased in multiple steps while maintaining the intensity at a sub-threshold level to avoid generating an action potential. Axonal conduction block by HFBS is defined as the failure of action potential propagation at the site of HFBS. The simulation analysis shows that step-increases in sub-threshold intensity during HFBS can successfully block axonal conduction without generating an initial response because the excitation threshold of the axon can be gradually increased by the sub-threshold HFBS. The mechanisms underlying the increase in excitation threshold involve changes in intracellular and extracellular sodium and potassium concentration, change in the resting potential, partial inactivation of the sodium channel and partial activation of the potassium channel by HFBS. When the excitation threshold reaches a sufficient level, an acute block occurs first and after additional sub-threshold HFBS it is followed by a post-stimulation block. This study indicates that step-increases in sub-threshold HFBS intensity induces a gradual increase in axonal excitation threshold that may allow HFBS to block nerve conduction without generating an initial response. If this finding is proven to be true in human, it will significantly impact clinical applications of HFBS to treat chronic pain.
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Affiliation(s)
- Yihua Zhong
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.,School of Biomedical Engineering, Capital Medical University, Beijing, P.R. China
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Beckel
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA. .,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA. .,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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Chen J, Jian J, Wang J, Shen Z, Shen B, Wang W, Beckel J, de Groat WC, Chermansky C, Tai C. Low pressure voiding induced by stimulation and 1 kHz post-stimulation block of the pudendal nerves in cats. Exp Neurol 2021; 346:113860. [PMID: 34487735 DOI: 10.1016/j.expneurol.2021.113860] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 08/27/2021] [Accepted: 09/01/2021] [Indexed: 11/28/2022]
Abstract
The goal of this study is to induce low-pressure voiding by stimulation and bilateral 1 kHz post-stimulation block of the pudendal nerves. In anesthetized cats, wire hook electrodes were placed on the left and/or right pudendal nerves. Stimulus pulses (30 Hz, 0.2 ms) were applied to one pudendal nerve to induce a reflex bladder contraction and to produce contractions of the external urethral sphincter (EUS). High frequency (1 kHz) biphasic stimulation was applied to block axonal conduction in both pudendal nerves and block EUS activity. In 4 cats, a catheter was inserted into the distal urethra to perfuse and measure the back pressure caused by the EUS contraction. In another 5 cats, a catheter was inserted into the bladder dome and the urethra was left open to allow voiding. The 1 kHz stimulation (30-60 s, 0.5-5 mA) delivered via a wire hook electrode completely blocked pudendal nerve conduction for ≥2 min after terminating the stimulation, i.e., a post-stimulation block. The block gradually disappeared in 6-18 min. The block duration increased with increasing amplitude or duration of the 1 kHz stimulation. Without the 1 kHz block, 30 Hz stimulation alone induced high-pressure (90 cmH2O) voiding. When combined with the 1 kHz block, the 30 Hz stimulation induced low-pressure (≤50 cmH2O) voiding with a high voiding efficiency (80%). In summary, a minimally invasive surgical approach might be developed to restore voiding function after spinal cord injury by stimulation and block of the pudendal nerves using lead electrodes.
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Affiliation(s)
- Jialiang Chen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Urology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, PR China
| | - Jianan Jian
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zhijun Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bing Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Beckel
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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