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Song W, Jayaprakash N, Saleknezhad N, Puleo C, Al-Abed Y, Martin JH, Zanos S. Transspinal Focused Ultrasound Suppresses Spinal Reflexes in Healthy Rats. Neuromodulation 2024; 27:614-624. [PMID: 37530695 DOI: 10.1016/j.neurom.2023.04.476] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 04/26/2023] [Accepted: 04/29/2023] [Indexed: 08/03/2023]
Abstract
OBJECTIVES Low-intensity, focused ultrasound (FUS) is an emerging noninvasive neuromodulation approach, with improved spatial and temporal resolution and penetration depth compared to other noninvasive electrical stimulation strategies. FUS has been used to modulate circuits in the brain and the peripheral nervous system, however, its potential to modulate spinal circuits is unclear. In this study, we assessed the effect of trans-spinal FUS (tsFUS) on spinal reflexes in healthy rats. MATERIALS AND METHODS tsFUS targeting different spinal segments was delivered for 1 minute, under anesthesia. Monosynaptic H-reflex of the sciatic nerve, polysynaptic flexor reflex of the sural nerve, and withdrawal reflex tested with a hot plate were measured before, during, and after tsFUS. RESULTS tsFUS reversibly suppresses the H-reflex in a spinal segment-, acoustic pressure- and pulse-repetition frequency (PRF)-dependent manner. tsFUS with high PRF augments the degree of homosynaptic depression of the H-reflex observed with paired stimuli. It suppresses the windup of components of the flexor reflex associated with slower, C-afferent, but not faster, A- afferent fibers. Finally, it increases the latency of the withdrawal reflex. tsFUS does not elicit neuronal loss in the spinal cord. CONCLUSIONS Our study provides evidence that tsFUS reversibly suppresses spinal reflexes and suggests that tsFUS could be a safe and effective strategy for spinal cord neuromodulation in disorders associated with hyperreflexia, including spasticity after spinal cord injury and painful syndromes.
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Affiliation(s)
- Weiguo Song
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Naveen Jayaprakash
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Nafiseh Saleknezhad
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Chris Puleo
- General Electric Research, Niskayuna, NY, USA
| | - Yousef Al-Abed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - John H Martin
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY; Elmezzi Graduate School of Molecular Medicine, Manhasset, NY.
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Khasabov SG, Malecha P, Noack J, Tabakov J, Giesler GJ, Simone DA. Hyperalgesia and sensitization of dorsal horn neurons following activation of NK-1 receptors in the rostral ventromedial medulla. J Neurophysiol 2017; 118:2727-2744. [PMID: 28794197 PMCID: PMC5675905 DOI: 10.1152/jn.00478.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/04/2017] [Accepted: 08/06/2017] [Indexed: 11/22/2022] Open
Abstract
Neurons in the rostral ventromedial medulla (RVM) project to the spinal cord and are involved in descending modulation of pain. Several studies have shown that activation of neurokinin-1 (NK-1) receptors in the RVM produces hyperalgesia, although the underlying mechanisms are not clear. In parallel studies, we compared behavioral measures of hyperalgesia to electrophysiological responses of nociceptive dorsal horn neurons produced by activation of NK-1 receptors in the RVM. Injection of the selective NK-1 receptor agonist Sar9,Met(O2)11-substance P (SSP) into the RVM produced dose-dependent mechanical and heat hyperalgesia that was blocked by coadministration of the selective NK-1 receptor antagonist L-733,060. In electrophysiological studies, responses evoked by mechanical and heat stimuli were obtained from identified high-threshold (HT) and wide dynamic range (WDR) neurons. Injection of SSP into the RVM enhanced responses of WDR neurons, including identified neurons that project to the parabrachial area, to mechanical and heat stimuli. Since intraplantar injection of capsaicin produces robust hyperalgesia and sensitization of nociceptive spinal neurons, we examined whether this sensitization was dependent on NK-1 receptors in the RVM. Pretreatment with L-733,060 into the RVM blocked the sensitization of dorsal horn neurons produced by capsaicin. c-Fos labeling was used to determine the spatial distribution of dorsal horn neurons that were sensitized by NK-1 receptor activation in the RVM. Consistent with our electrophysiological results, administration of SSP into the RVM increased pinch-evoked c-Fos expression in the dorsal horn. It is suggested that targeting this descending pathway may be effective in reducing persistent pain.NEW & NOTEWORTHY It is known that activation of neurokinin-1 (NK-1) receptors in the rostral ventromedial medulla (RVM), a main output area for descending modulation of pain, produces hyperalgesia. Here we show that activation of NK-1 receptors produces hyperalgesia by sensitizing nociceptive dorsal horn neurons. Targeting this pathway at its origin or in the spinal cord may be an effective approach for pain management.
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Affiliation(s)
- Sergey G Khasabov
- Department of Diagnostic and Biological Sciences, University of Minnesota, School of Dentistry, Minneapolis, Minnesota; and
| | - Patrick Malecha
- Department of Diagnostic and Biological Sciences, University of Minnesota, School of Dentistry, Minneapolis, Minnesota; and
| | - Joseph Noack
- Department of Diagnostic and Biological Sciences, University of Minnesota, School of Dentistry, Minneapolis, Minnesota; and
| | - Janneta Tabakov
- Department of Diagnostic and Biological Sciences, University of Minnesota, School of Dentistry, Minneapolis, Minnesota; and
| | - Glenn J Giesler
- Department of Neuroscience, University of Minnesota, School of Medicine, Minneapolis, Minnesota
| | - Donald A Simone
- Department of Diagnostic and Biological Sciences, University of Minnesota, School of Dentistry, Minneapolis, Minnesota; and
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Electroacupuncture in conscious free-moving mice reduces pain by ameliorating peripheral and central nociceptive mechanisms. Sci Rep 2016; 6:34493. [PMID: 27687125 PMCID: PMC5043286 DOI: 10.1038/srep34493] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/14/2016] [Indexed: 11/08/2022] Open
Abstract
Integrative approaches such as electroacupuncture, devoid of drug effects are gaining prominence for treating pain. Understanding the mechanisms of electroacupuncture induced analgesia would benefit chronic pain conditions such as sickle cell disease (SCD), for which patients may require opioid analgesics throughout life. Mouse models are instructive in developing a mechanistic understanding of pain, but the anesthesia/restraint required to administer electroacupuncture may alter the underlying mechanisms. To overcome these limitations, we developed a method to perform electroacupuncture in conscious, freely moving, unrestrained mice. Using this technique we demonstrate a significant analgesic effect in transgenic mouse models of SCD and cancer as well as complete Freund's adjuvant-induced pain. We demonstrate a comprehensive antinociceptive effect on mechanical, cold and deep tissue hyperalagesia in both genders. Interestingly, individual mice showed a variable response to electroacupuncture, categorized into high-, moderate-, and non-responders. Mechanistically, electroacupuncture significantly ameliorated inflammatory and nociceptive mediators both peripherally and centrally in sickle mice correlative to the antinociceptive response. Application of sub-optimal doses of morphine in electroacupuncture-treated moderate-responders produced equivalent antinociception as obtained in high-responders. Electroacupuncture in conscious freely moving mice offers an effective approach to develop a mechanism-based understanding of analgesia devoid of the influence of anesthetics or restraints.
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Guan Y, Raja SN. Wide-dynamic-range neurons are heterogeneous in windup responsiveness to changes in stimulus intensity and isoflurane anesthesia level in mice. J Neurosci Res 2010; 88:2272-83. [PMID: 20209628 DOI: 10.1002/jnr.22383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The windup phenomenon in wide-dynamic-range (WDR) neurons represents a short-term neuronal sensitization to repetitive noxious inputs that may share similar mechanisms with those that trigger the development of persistent pain and hyperalgesia. Some WDR cells are readily sensitized and express prominent windup (windup(+)), whereas others do not (windup(-)). We recorded extracellular single-unit activity of deep laminae WDR neurons (350-700 microm) in C57BL/6 mice to determine how changes in stimulus intensity (1x and >2x C-component threshold, n = 53) and concentrations of isoflurane anesthesia (2.0% and 1.0%, n = 30) might differently modulate windup responsiveness in windup(+) and windup(-) cells. Two principally different analysis methods [absolute windup (the number of action potentials) and relative windup (the percentage of action potentials evoked by the first stimulus of the train)] were used to interpret windup data. We observed that increasing the stimulus intensity and decreasing the isoflurane concentration: 1) facilitated windup generation at 0.2-Hz stimulation and significantly enhanced absolute windup at both 0.2-Hz and 0.5-Hz stimulation predominantly in windup(+) cells but did not confer windup capability on windup(-) cells and 2) significantly increased relative windup at 0.2-Hz, but not 0.5-Hz, stimulation in windup(+) cells. Our findings advance our understanding of the neurobiology of deep WDR neurons in mice and demonstrate that two populations of cells differ in their windup responsiveness to changes in experimental conditions. We also elucidate the usefulness and potential limitations of two widely used methods for calculating and presenting windup data.
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Affiliation(s)
- Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Spadavecchia C, Levionnois O, Kronen P, Andersen OK. The effects of isoflurane minimum alveolar concentration on withdrawal reflex activity evoked by repeated transcutaneous electrical stimulation in ponies. Vet J 2010; 183:337-44. [DOI: 10.1016/j.tvjl.2008.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 12/22/2008] [Accepted: 12/22/2008] [Indexed: 11/25/2022]
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Dutton RC, Cuellar JM, Eger EI, Antognini JF, Carstens E. Temporal and Spatial Determinants of Sacral Dorsal Horn Neuronal Windup in Relation to Isoflurane-Induced Immobility. Anesth Analg 2007; 105:1665-74, table of contents. [DOI: 10.1213/01.ane.0000286175.46760.9f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Ng KP, Antognini JF. Isoflurane and Propofol Have Similar Effects on Spinal Neuronal Windup at Concentrations that Block Movement. Anesth Analg 2006; 103:1453-8. [PMID: 17122222 DOI: 10.1213/01.ane.0000247732.33602.f5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND We investigated the actions of isoflurane and propofol on neuronal windup in the spinal cord of intact rats. We hypothesized that propofol would depress windup more than isoflurane. METHODS In a cross-over design, rats received 0.8 and 1.2 minimum alveolar concentration (MAC) isoflurane and 0.8 and 1.2 ED50 (effective dose(50%)) of propofol, as recordings were made from single units in the lumbar cord (n = 13). Electrical stimuli were applied (20 stimuli at 0.1, 1, and 3 Hz). Neuronal responses were analyzed for those occurring in the C-fiber range (100-400 ms after each stimulus), combined C-fiber and afterdischarge range (100-1000 ms) and the 100-333 ms range for the 3 Hz stimuli. Absolute windup was also calculated (the sum of action potentials for 20 stimuli - 20 x response to the first stimulus). RESULTS At 1 Hz, total action potentials (mean, standard error) summed across the 20 stimuli (100-1000 ms range) were 571 +/- 106 and 742 +/- 214 for isoflurane (at 0.8 and 1.2 MAC) and 586 +/- 148 and 641 +/- 143 for propofol (at 0.8 and 1.2 ED50), respectively (P = NS); corresponding values for the 0.1 Hz stimuli were 345 +/- 104, 370 +/- 108, 430 +/- 86, and 403 +/- 106 (P = NS), and for the 3 Hz stimuli (100-333 ms range) were 266 +/- 66, 333 +/- 76, 343 +/- 85, and 252 +/- 72 (P = NS). Absolute windup in the 100-1000 ms range was greater for 1.2 MAC isoflurane at 1 Hz (445 +/- 82, P < 0.01), when compared with absolute windup at 0.8 MAC isoflurane and 0.8 and 1.2 ED50 propofol (232 +/- 31, 88 +/- 65, and 210 +/- 41, respectively). CONCLUSIONS These data suggest that isoflurane and propofol have similar effects on neuronal windup in the spinal cord, although there was enhanced absolute windup at 1.2 MAC isoflurane for the 1 Hz stimulus.
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Affiliation(s)
- Kevin P Ng
- Department of Anesthesiology and Pain Medicine, University of California, Davis, Davis, California 95616, USA
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Mitsuyo T, Dutton RC, Antognini JF, Carstens E. The differential effects of halothane and isoflurane on windup of dorsal horn neurons selected in unanesthetized decerebrated rats. Anesth Analg 2006; 103:753-60. [PMID: 16931692 DOI: 10.1213/01.ane.0000230605.22930.52] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Halothane and isoflurane, in the peri-minimum alveolar anesthetic concentration (MAC) range, exert differential effects on spinal nociceptive neurons, whereby halothane further depresses their responses from 0.8 to 1.2 MAC, whereas isoflurane does not. We presently investigated if these anesthetics differentially affect windup, the progressive increase in neuronal responses to repetitive noxious stimuli, over a broad concentration range from 0 to 1.2 MAC. In decerebrated rats, single-unit recordings were made from dorsal horn neurons exhibiting windup to 20 1-Hz C-fiber strength electrical stimuli. Halothane and isoflurane (0, 0.4, 0.8, and 1.2 MAC) were tested in a counterbalanced crossover protocol. Increasing halothane and isoflurane from 0 to 1.2 MAC progressively suppressed the response to the first stimulus, as well as summed responses to all stimuli (to 34% +/- 8% and 50% +/- 8%, respectively; P < 0.05). Absolute windup (summed response minus 20x the first response) was suppressed by both anesthetics from 0 to 0.8 MAC, with further depression by halothane but not isoflurane at 1.2 MAC. Responses of neurons isolated at 0 MAC were partially, but never totally, depressed at 0.8 MAC. The dose-dependent suppression of windup is consistent with reduced temporal summation of pain. Further depression at 1.2 MAC halothane, but not isoflurane, suggests different sites of immobilizing action for these two anesthetics. Immobility seems to not be mediated by severe anesthetic depression of a subpopulation of nociceptive neurons.
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Affiliation(s)
- Toshihiko Mitsuyo
- Department of Anesthesiology and Resuscitology, Ehime University Medical School, Matsuyama, Japan
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Barter L, Dominguez CL, Carstens E, Antognini JF. The effect of isoflurane and halothane on electroencephalographic activation elicited by repetitive noxious c-fiber stimulation. Neurosci Lett 2005; 382:242-7. [PMID: 15925098 DOI: 10.1016/j.neulet.2005.03.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Revised: 02/02/2005] [Accepted: 03/11/2005] [Indexed: 11/17/2022]
Abstract
Windup is the progressive increase in neuronal response to a repetitive noxious stimulus. This response is most often observed in the spinal cord, but it is unclear how this response is manifested in supraspinal structures. We investigated the effects of isoflurane and halothane on electroencephalographic responses to repetitive noxious electrical stimuli (20 pulses at 0.1, 1 and 3 Hz) applied to the tail in rats. Halothane and isoflurane concentrations were adjusted to 0.8 and 1.2 minimum alveolar concentration (MAC), where MAC is the concentration needed to prevent gross and purposeful movement in 50% of animals. At 0.8 MAC halothane, the 3 Hz stimulus caused electroencephalographic (EEG) activation primarily by increasing the median edge frequency (MEF), while at 1.2 MAC halothane the spectral edge frequency (SEF) was increased by the 1 and 3 Hz stimuli, and the MEF was increased by the 3 Hz stimuli. At 0.8 MAC isoflurane, the 1 and 3 Hz stimuli evoked EEG activation by increasing the MEF and SEF, while at 1.2 MAC only the MEF was increased by the 1 Hz stimulus. No EEG activation occurred with the 0.1 Hz repetitive stimulus with either isoflurane or halothane. These data suggest that repetitive electrical stimulation normally associated with windup in spinal neurons can evoke EEG activation.
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Affiliation(s)
- Linda Barter
- Department of Anesthesiology and Pain Medicine, University of California, Davis, CA 95616, USA
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Cuellar JM, Dutton RC, Antognini JF, Carstens E. Differential effects of halothane and isoflurane on lumbar dorsal horn neuronal windup and excitability. Br J Anaesth 2005; 94:617-25. [PMID: 15734781 DOI: 10.1093/bja/aei107] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Windup of spinal nociceptive neurones may underlie temporal summation of pain, influencing the minimum alveolar concentration (MAC) of anaesthetics required to prevent movement to supramaximal stimuli. We hypothesized that halothane and isoflurane would differentially affect windup of dorsal horn neurones. METHODS We recorded 18 nociceptive dorsal horn neurones exhibiting windup to 1 Hz electrical hindpaw stimuli in rats. Effects of 0.8 and 1.2 MAC isoflurane and halothane were recorded in the same neurones (counterbalanced, crossover design). Windup was calculated as the total number of C-fibre (100-400 ms latency) plus afterdischarge (400-1000 ms latency) spikes/20 stimuli (area under curve, AUC) or absolute windup (C-fibre plus afterdischarge-20 x initial response). RESULTS Increasing isoflurane from 0.8 to 1.2 MAC did not affect AUC, but increased absolute windup from 429 (62) to 618 (84) impulses/20 stimuli (P<0.05) and depressed the initial C-fibre response from 14 (3) to 8 (2) impulses (P<0.05). Increasing halothane from 0.8 to 1.2 MAC depressed AUC from 690 (79) to 537 (65) impulses/20 stimuli (P<0.05) and the initial response from 18 (2) to 13 (2) impulses (P<0.05), but absolute windup was not affected. Absolute windup was 117% greater during 1.2 MAC isoflurane compared with 1.2 MAC halothane. CONCLUSIONS Windup was significantly greater under isoflurane than halothane anaesthesia at 1.2 MAC, whereas the initial C-fibre response was suppressed more by isoflurane. These findings suggest that these two anaesthetics have mechanistically distinct effects on neuronal windup and excitability.
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