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Abd-Elsayed A, Vardhan S, Aggarwal A, Vardhan M, Diwan SA. Mechanisms of Action of Dorsal Root Ganglion Stimulation. Int J Mol Sci 2024; 25:3591. [PMID: 38612402 PMCID: PMC11011701 DOI: 10.3390/ijms25073591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/12/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
The dorsal root ganglion (DRG) serves as a pivotal site for managing chronic pain through dorsal root ganglion stimulation (DRG-S). In recent years, the DRG-S has emerged as an attractive modality in the armamentarium of neuromodulation therapy due to its accessibility and efficacy in alleviating chronic pain refractory to conventional treatments. Despite its therapeutic advantages, the precise mechanisms underlying DRG-S-induced analgesia remain elusive, attributed in part to the diverse sensory neuron population within the DRG and its modulation of both peripheral and central sensory processing pathways. Emerging evidence suggests that DRG-S may alleviate pain by several mechanisms, including the reduction of nociceptive signals at the T-junction of sensory neurons, modulation of pain gating pathways within the dorsal horn, and regulation of neuronal excitability within the DRG itself. However, elucidating the full extent of DRG-S mechanisms necessitates further exploration, particularly regarding its supraspinal effects and its interactions with cognitive and affective networks. Understanding these mechanisms is crucial for optimizing neurostimulation technologies and improving clinical outcomes of DRG-S for chronic pain management. This review provides a comprehensive overview of the DRG anatomy, mechanisms of action of the DRG-S, and its significance in neuromodulation therapy for chronic pain.
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Affiliation(s)
- Alaa Abd-Elsayed
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53792, USA
| | - Swarnima Vardhan
- Department of Internal Medicine, Yale New Haven Health, Bridgeport Hospital, Bridgeport, CT 06605, USA; (S.V.); (A.A.)
- Advanced Spine on Park Avenue, New York, NY 10461, USA;
| | - Abhinav Aggarwal
- Department of Internal Medicine, Yale New Haven Health, Bridgeport Hospital, Bridgeport, CT 06605, USA; (S.V.); (A.A.)
| | - Madhurima Vardhan
- Argonne Leadership Computing Facility, Argonne National Laboratory, Lemont, IL 60439, USA;
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Chapman KB, Sayed D, Lamer T, Hunter C, Weisbein J, Patel KV, Dickerson D, Hagedorn JM, Lee DW, Amirdelfan K, Deer T, Chakravarthy K. Best Practices for Dorsal Root Ganglion Stimulation for Chronic Pain: Guidelines from the American Society of Pain and Neuroscience. J Pain Res 2023; 16:839-879. [PMID: 36942306 PMCID: PMC10024474 DOI: 10.2147/jpr.s364370] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 01/17/2023] [Indexed: 03/14/2023] Open
Abstract
With continued innovations in neuromodulation comes the need for evolving reviews of best practices. Dorsal root ganglion stimulation (DRG-S) has significantly improved the treatment of complex regional pain syndrome (CRPS), and it has broad applicability across a wide range of other conditions. Through funding and organizational leadership by the American Society for Pain and Neuroscience (ASPN), this best practices consensus document has been developed for the selection, implantation, and use of DRG stimulation for the treatment of chronic pain syndromes. This document is composed of a comprehensive narrative literature review that has been performed regarding the role of the DRG in chronic pain and the clinical evidence for DRG-S as a treatment for multiple pain etiologies. Best practice recommendations encompass safety management, implantation techniques, and mitigation of the potential complications reported in the literature. Looking to the future of neuromodulation, DRG-S holds promise as a robust intervention for otherwise intractable pain.
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Affiliation(s)
- Kenneth B Chapman
- The Spine & Pain Institute of New York, New York, NY, USA
- Department of Anesthesiology, Zucker School of Medicine at Hofstra Northwell, Manhasset, NY, USA
- Department of Anesthesiology, NYU Langone Medical Center, New York, NY, USA
- Correspondence: Kenneth B Chapman, NYU Langone Medical Center, Zucker School of Medicine at Hofstra/Northwell, Pain Medicine at Staten Island University Hospital, 1360 Hylan Boulevard, Staten Island, NY, 10305, USA, Email
| | - Dawood Sayed
- Department of Anesthesiology, The University of Kansas Medical Center (KUMC), Kansas City, KS, USA
| | - Tim Lamer
- Department of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA
| | - Corey Hunter
- Ainsworth Institute of Pain Management, New York, NY, USA
| | | | - Kiran V Patel
- The Spine & Pain Institute of New York, New York, NY, USA
- Department of Anesthesiology, Zucker School of Medicine at Hofstra Northwell, Manhasset, NY, USA
- Department of Anesthesiology, NYU Langone Medical Center, New York, NY, USA
| | - David Dickerson
- Department of Anesthesiology, Critical Care and Pain Medicine, NorthShore University Health System, Evanston, IL, USA
- Department of Anesthesia & Critical Care, University of Chicago, Chicago, IL, USA
| | | | - David W Lee
- Fullerton Orthopedic Surgery Medical Group, Fullerton, CA, USA
| | | | - Timothy Deer
- The Spine and Nerve Center of the Virginias, Charleston, WV, USA
| | - Krishnan Chakravarthy
- Department of Anesthesiology and Pain Medicine, University of California San Diego Health Sciences, San Diego, CA, USA
- VA San Diego Healthcare System, San Diego, CA, USA
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Lund AM, Hannibal J. Localization of the neuropeptides pituitary adenylate cyclase-activating polypeptide, vasoactive intestinal peptide, and their receptors in the basal brain blood vessels and trigeminal ganglion of the mouse CNS; an immunohistochemical study. Front Neuroanat 2022; 16:991403. [PMID: 36387999 PMCID: PMC9643199 DOI: 10.3389/fnana.2022.991403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/04/2022] [Indexed: 11/26/2022] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are structurally related neuropeptides that are widely expressed in vertebrate tissues. The two neuropeptides are pleiotropic and have been associated with migraine pathology. Three PACAP and VIP receptors have been described: PAC1, VPAC1, and VPAC2. The localization of these receptors in relation to VIP and PACAP in migraine-relevant structures has not previously been shown in mice. In the present study, we used fluorescence immunohistochemistry, well-characterized antibodies, confocal microscopy, and three-dimensional reconstruction to visualize the distribution of PACAP, VIP, and their receptors in the basal blood vessels (circle of Willis), trigeminal ganglion, and brain stem spinal trigeminal nucleus (SP5) of the mouse CNS. We demonstrated a dense network of circularly oriented VIP fibers on the basal blood vessels. PACAP nerve fibers were fewer in numbers compared to VIP fibers and ran along the long axis of the blood vessels, colocalized with calcitonin gene-related peptide (CGRP). The nerve fibers expressing CGRP are believed to be sensorial, with neuronal somas localized in the trigeminal ganglion and PACAP was found in a subpopulation of these CGRP-neurons. Immunostaining of the receptors revealed that only the VPAC1 receptor was present in the basal blood vessels, localized on the surface cell membrane of vascular smooth muscle cells and innervated by VIP fibers. No staining was seen for the PAC1, VPAC1, or VPAC2 receptor in the trigeminal ganglion. However, distinct PAC1 immunoreactivity was found in neurons innervated by PACAP nerve terminals located in the spinal trigeminal nucleus. These findings indicate that the effect of VIP is mediated via the VPAC1 receptor in the basal arteries. The role of PACAP in cerebral arteries is less clear. The localization of PACAP in a subpopulation of CGRP-expressing neurons in the trigeminal ganglion points toward a primary sensory function although a dendritic release cannot be excluded which could stimulate the VPAC1 receptor or the PAC1 and VPAC2 receptors on immune cells in the meninges, initiating neurogenic inflammation relevant for migraine pathology.
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Affiliation(s)
- Anne Marie Lund
- Faculty of Health and Medical Sciences, Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Faculty of Health Sciences, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Jens Hannibal
- Faculty of Health and Medical Sciences, Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Faculty of Health Sciences, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Jens Hannibal,
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Chapman KB, Kloosterman J, Schor JA, Girardi GE, van Helmond N, Yousef TA. Objective Improvements in Peripheral Arterial Disease from Dorsal Root Ganglion Stimulation: A Case Series. Ann Vasc Surg 2021; 74:519.e7-519.e16. [PMID: 33549777 DOI: 10.1016/j.avsg.2021.01.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/02/2021] [Accepted: 01/05/2021] [Indexed: 11/25/2022]
Abstract
BACKGROUND The sympathetic nervous system (SNS) is important in the regulation of perfusion. Dorsal root ganglion stimulation (DRG-S) modulates sympathetic tone and is approved to treat complex regional pain syndrome, a disorder related to SNS dysfunction. We herein present 3 cases of DRG-S therapy to improve blood flow and symptoms of ischemia in peripheral arterial disease (PAD). METHODS Patient 1 is a 44-year-old female with dry gangrene of the third and fourth digits of her right hand due to Raynaud's syndrome who was scheduled for amputation of the affected digits. DRG-S leads were placed at the right C6, 7, and 8 DRG. Pulse volume recordings (PVR) were measured at baseline and after DRG-S. Patient 2 is a 55-year-old female with a non-healing ulcer of her left foot secondary to PAD scheduled for a below the knee amputation who underwent a DRG-S trial with leads placed at the left L4 and L5 DRG followed by a spinal cord stimulation trial with leads placed at the T9-T10 spinal levels for comparison. Transcutaneous oximetry (TcPO2) was measured at baseline and after 3 days of each therapy. Patient 3 is a 69-year-old female with persistent left foot pain at rest secondary to PAD with DRG-S leads placed at the left L4 and S1 levels. RESULTS All 3 patients experienced a significant reduction in pain with DRG-S, along with improvements in blood flow of the involved extremities, avoiding or limiting amputation. PVR improved dramatically with DRG-S in patient 1. A greater improvement in TcPO2 was seen with the DRG-S trial compared to spinal cord stimulation trial in patient 2. Patient 3 experienced an increase in walking distance and demonstrated long term efficacy and limb salvage at 32 months postimplantation. CONCLUSIONS Modulation of SNS output from DRG-S through orthodromic and antidromic autonomic pathways is likely responsible for improving blood flow. DRG-S may be a treatment option for PAD.
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Affiliation(s)
- Kenneth B Chapman
- Spine & Pain Institute of New York, New York City, NY; Department of Anesthesiology, New York University Langone Medical Center, New York City, NY; Zucker School of Medicine at Hofstra/Northwell, New York City, NY.
| | - Jaap Kloosterman
- College of Medicine, Radboud University, Nijmegen, The Netherlands
| | - Jonathan A Schor
- Department of Surgery, Division of Vascular Surgery, Staten Island University Hospital, New York, NY
| | | | - Noud van Helmond
- Spine & Pain Institute of New York, New York City, NY; Department of Anesthesiology, Cooper Medical School of Rowan University, Cooper University Hospital, Camden, NJ
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Shreckengost J, Halder M, Mena-Avila E, Garcia-Ramirez DL, Quevedo J, Hochman S. Nicotinic receptor modulation of primary afferent excitability with selective regulation of Aδ-mediated spinal actions. J Neurophysiol 2020; 125:568-585. [PMID: 33326305 DOI: 10.1152/jn.00228.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Somatosensory input strength can be modulated by primary afferent depolarization (PAD) generated predominantly via presynaptic GABAA receptors on afferent terminals. We investigated whether ionotropic nicotinic acetylcholine receptors (nAChRs) also provide modulatory actions, focusing on myelinated afferent excitability in in vitro murine spinal cord nerve-attached models. Primary afferent stimulation-evoked synaptic transmission was recorded in the deep dorsal horn as extracellular field potentials (EFPs), whereas concurrently recorded dorsal root potentials (DRPs) were used as an indirect measure of PAD. Changes in afferent membrane excitability were simultaneously measured as direct current (DC)-shifts in membrane polarization recorded in dorsal roots or peripheral nerves. The broad nAChR antagonist d-tubocurarine (d-TC) selectively and strongly depressed Aδ-evoked synaptic EFPs (36% of control) coincident with similarly depressed A-fiber DRP (43% of control), whereas afferent electrical excitability remained unchanged. In comparison, acetylcholine (ACh) and the nAChR agonists, epibatidine and nicotine, reduced afferent excitability by generating coincident depolarizing DC-shifts in peripheral axons and intraspinally. Progressive depolarization corresponded temporally with the emergence of spontaneous axonal spiking and reductions in the DRP and all afferent-evoked synaptic actions (31%-37% of control). Loss of evoked response was long-lasting, independent of DC repolarization, and likely due to mechanisms initiated by spontaneous C-fiber activity. DC-shifts were blocked with d-TC but not GABAA receptor blockers and retained after tetrodotoxin block of voltage-gated Na+ channels. Notably, actions tested were comparable between three mouse strains, in rat, and when performed in different labs. Thus, nAChRs can regulate afferent excitability via two distinct mechanisms: by central Aδ-afferent actions, and by transient extrasynaptic axonal activation of high-threshold primary afferents.NEW & NOTEWORTHY Primary afferents express many nicotinic ACh receptor (nAChR) subtypes but whether activation is linked to presynaptic inhibition, facilitation, or more complex and selective activity modulation is unknown. Recordings of afferent-evoked responses in the lumbar spinal cord identified two nAChR-mediated modulatory actions: 1) selective control of Aδ afferent transmission and 2) robust changes in axonal excitability initiated via extrasynaptic shifts in DC polarization. This work broadens the diversity of presynaptic modulation of primary afferents by nAChRs.
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Affiliation(s)
| | - Mallika Halder
- Department of Physiology, Emory University, Atlanta, Georgia
| | - Elvia Mena-Avila
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - David Leonardo Garcia-Ramirez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Jorge Quevedo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Shawn Hochman
- Department of Physiology, Emory University, Atlanta, Georgia
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Chapman KB, Van Roosendaal BKW, Van Helmond N, Yousef TA. Unilateral Dorsal Root Ganglion Stimulation Lead Placement With Resolution of Bilateral Lower Extremity Symptoms in Diabetic Peripheral Neuropathy. Cureus 2020; 12:e10735. [PMID: 33145140 PMCID: PMC7599049 DOI: 10.7759/cureus.10735] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Dorsal root ganglion stimulation (DRG-S) is a form of neuromodulation that can target specific dermatomes to obtain better coverage of the distal extremity. Previously proposed mechanisms of action for DRG-S focused on the dorsal root ganglion (DRG) itself, without consideration of orthodromic effects in the dorsal horn and antidromic effects on the nerve root and sympathetic chain. Diabetic peripheral neuropathy (DPN) is an axonal neuropathy that affects around half of all patients with diabetes mellitus, causing severe pain and sensory impairment in the distal extremities. We present a case of a patient with DPN in both feet, in addition to low back pain, who underwent a DRG-S trial with right T12 and S1 leads. The trial was performed unilaterally for seven days, allowing the patient to compare the treated versus the untreated (left) side. Pain, disability, general health status, and quality of life measures improved significantly. In addition to the significant pain relief in the low back and feet, the patient had near resolution of other DPN-related symptoms, including numbness, bluish discoloration, and allodynia of both feet. He also demonstrated functional and psychological benefits with only a single-sided lead. Overall, the placement of unilateral T12 and S1 DRG-S leads resulted in symmetric improvement of DPN symptoms. A possible mechanism of action is antidromic propagation of action potential signaling into the sympathetic chain to a central ganglion and then to the contralateral sympathetic chain. Given the DRG's ability to directly affect afferent sympathetic fibers with low-frequency stimulation, DRG-S may be an effective neuromodulatory treatment for DPN.
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Affiliation(s)
- Kenneth B Chapman
- Pain Management, Hofstra Medical School/Northwell Health Systems, New York, USA.,Anesthesiology/Pain Management, New York University Langone Medical Center, New York, USA
| | | | - Noud Van Helmond
- Anesthesiology, Cooper Medical School of Rowan University, Camden, USA
| | - Tariq A Yousef
- Pain Management, The Spine and Pain Institute of New York, New York, USA
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Wang YL, Su YS, He W, Jing XH. Electroacupuncture relieved visceral and referred hindpaw hypersensitivity in colitis rats by inhibiting tyrosine hydroxylase expression in the sixth lumbar dorsal root ganglia. Neuropeptides 2019; 77:101957. [PMID: 31400959 DOI: 10.1016/j.npep.2019.101957] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/27/2019] [Accepted: 07/21/2019] [Indexed: 12/12/2022]
Abstract
Irritable bowel syndrome patients frequently complain of pain in body regions somatotopically distinct from the gut, suggesting the involvement of an exaggerated signaling process in both visceral and somatic sensory pathways. Increasing evidence has shown that sprouting of tyrosine hydroxylase immunoreactive (TH-IR) fibers toward sensory neurons in dorsal root ganglia maintains and exacerbates the neuropathic and inflammatory pain, as well as colonic inflammation. The aim of the present study was to determine whether electroacupuncture could alleviate the visceral and secondary somatic hyperalgesia in colitis rats by suppressing the TH-IR expression in related dorsal root ganglia. After trinitrobenzene sulfonic acid irritation, rats developed inflammatory tissue damage in the distal colon, which was accompanied by visceral hypersensitivity and secondary hind paw hyperalgesia, as indicated by enhanced visceromotor response to colorectal distension and decreased mechanical and thermal withdrawal latency of the hind paw. Additionally, excessive TH-IR fibers sprouted toward calcitonin gene-related peptide immunoreactive sensory neurons, and TH-IR neurons also increased in the sixth lumbar dorsal root ganglia of colitis rats. Both electroacupuncture and guanethidine attenuated visceral and referred hind paw hyperalgesia by inhibiting the over-expression of TH-IR neurons and fibers in the sixth lumbar dorsal root ganglia. Moreover local inflammatory damage in the distal colon was restored after 7 days of electroacupuncture intervention. These results suggest that electroacupuncture relieved visceral and referred hind paw hypersensitivity in colitis rats by inhibiting TH expression in the sixth lumbar dorsal root ganglia.
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Affiliation(s)
- Yi Li Wang
- Research Center of Meridians, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yang Shuai Su
- Research Center of Meridians, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Wei He
- Research Center of Meridians, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China.
| | - Xiang Hong Jing
- Research Center of Meridians, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China.
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Wang S, Liu K, Wang Y, Wang S, He X, Cui X, Gao X, Zhu B. A Proposed Neurologic Pathway for Scalp Acupuncture: Trigeminal Nerve-Meninges-Cerebrospinal Fluid-Contacting Neurons-Brain. Med Acupunct 2017; 29:322-326. [PMID: 29067143 DOI: 10.1089/acu.2017.1231] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Objective: Scalp acupuncture is a somatic stimulation therapy that produces prominent clinical effects when used to treat cerebral diseases. However, this acupuncture's therapeutic mechanisms have not yet been well-addressed. Scalp acupoints are innervated by the trigeminal nerve, which is coincident with the intracranial sensory afferents as well as with the meningeal vessels. In recent years, cerebrospinal fluid-contacting neurons have been found and proved to transmit allergic substances between brain the parenchyma and meninges, representing a possible network between scalp acupuncture and the brain. The aim of the current study was to observe the connections between scalp acupoints and the meninges and to establish a possible mechanism for scalp acupuncture. Materials and Methods: Twenty-five adult Sprague-Dawley rats were used for the present study. Evans Blue dye (Sigma Chemical Co, St. Louis, MO) was injected though each rat's caudal vein after trigeminal stimulation for plasma extravasation observation. Cerebral blood flow (CBF) values of the rat's brain surface were measured at different timepoints before and after electroacupuncture (EA) on GB 15 (Toulinqi) or ST 36 (Zusanli). Results: These preliminary studies indicated that neurogenic plasma extravasation on a rat's skin and dura mater after mechanical or electrical stimulation of the trigeminal nerves is a reliable way to show the pathologic connection between scalp acupoints and the meninges. Moreover, CBF of the rat's brain surface is increased significantly after EA stimulation at GB 15 (Toulinqi), which is located in the receptive field of the supraorbital nerve. Conclusions: These findings suggest that the mechanism of scalp acupuncture might lie in the specific neurologic pathway that could be termed as trigeminal nerve-meninges-cerebrospinal fluid-contacting neurons-brain, which is a possible shortcut to brain functional regulation and cerebral disease treatment.
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Affiliation(s)
- Shuya Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Kun Liu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yuan Wang
- Combination of Acupuncture and Medicine Innovation Research Center, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Shuyou Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xun He
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiang Cui
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xinyan Gao
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Bing Zhu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
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Iyengar S, Ossipov MH, Johnson KW. The role of calcitonin gene-related peptide in peripheral and central pain mechanisms including migraine. Pain 2017; 158:543-559. [PMID: 28301400 PMCID: PMC5359791 DOI: 10.1097/j.pain.0000000000000831] [Citation(s) in RCA: 347] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/09/2016] [Accepted: 12/22/2016] [Indexed: 12/25/2022]
Abstract
Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide found primarily in the C and Aδ sensory fibers arising from the dorsal root and trigeminal ganglia, as well as the central nervous system. Calcitonin gene-related peptide was found to play important roles in cardiovascular, digestive, and sensory functions. Although the vasodilatory properties of CGRP are well documented, its somatosensory function regarding modulation of neuronal sensitization and of enhanced pain has received considerable attention recently. Growing evidence indicates that CGRP plays a key role in the development of peripheral sensitization and the associated enhanced pain. Calcitonin gene-related peptide is implicated in the development of neurogenic inflammation and it is upregulated in conditions of inflammatory and neuropathic pain. It is most likely that CGRP facilitates nociceptive transmission and contributes to the development and maintenance of a sensitized, hyperresponsive state not only of the primary afferent sensory neurons but also of the second-order pain transmission neurons within the central nervous system, thus contributing to central sensitization as well. The maintenance of a sensitized neuronal condition is believed to be an important factor underlying migraine. Recent successful clinical studies have shown that blocking the function of CGRP can alleviate migraine. However, the mechanisms through which CGRP may contribute to migraine are still not fully understood. We reviewed the role of CGRP in primary afferents, the dorsal root ganglion, and in the trigeminal system as well as its role in peripheral and central sensitization and its potential contribution to pain processing and to migraine.
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He W, Wang XY, Shi H, Bai WZ, Cheng B, Su YS, Yu XC, Jing XH, Zhu B. Cutaneous neurogenic inflammation in the sensitized acupoints induced by gastric mucosal injury in rats. Altern Ther Health Med 2017; 17:141. [PMID: 28270193 PMCID: PMC5341424 DOI: 10.1186/s12906-017-1580-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 01/12/2017] [Indexed: 11/10/2022]
Abstract
BACKGROUND In acupuncture practice, the most important step is to confirm the location of a sensitized acupoint which reflects a diagnosis and can be stimulated with a specialized needle to treat the disease. Abnormal symptoms such as hyperalgesia or allodynia at the sensitized acupoints in patients with visceral disorders are considered to be in relation with referred pain and neurogenic inflammation. Yet, limited study has investigated the cutaneous neurochemical changes of the sensitized acuponits. METHODS The resent study developed an animal model of gastric mucosal injury (GMI) by HCl administered into the stomach of the rats. Evans Blue (EB) dye was applied by injection of tail vein after mucosal damage to observe the neurogenic plasma extravasation dots in the skin of the rats. The EB dots extravagated in the skin were compared with locations of acupoints. Immnohistochemistry analysis was used to detect the expression of calcitonin gene-related peptide (CGRP)- or substance P (SP)-labeled nerve fibers, histamine (HA)-, serotonin (5-HT)-, and tryptase-labeled cells in EB dots. Images were recorded and analyzed by Confocal imaging system and Olympus Image Processing Software. RESULTS The results showed that GMI resulted in neurogenic plasma extravasation in the skin of the acupoints over the back and abdomen, which mostly occurred in the T9-11 dermatomere. The EB extravasation dots appeared after GMI and disappeared gradually during the natural self-recovery of the gastric mucosa. More SP and CGRP positive nerve fibers were distributed in EB dots than that in regions beside EB dots and in the control, mostly distributed in the nerve fibers around both the vessels and root of hair follicle. Mast cells also aggregated and degranulated to release algogenic substances of 5-HT and HA around the vessels in areas of the EB dots. CONCLUSIONS Our results indicates that the mechanism of EB extravasation in the skin of the acupoints induced by GMI are closely related to neurogenic inflammation, and that the high expression of local allergic substances and nociceptive neuropeptides in the local skin including SP, CGRP, HA, 5-HT, and mast cell tryptase may be the underlying mechanism of the acupoint sensitization.
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11
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Lobanov OV, Peng YB. Differential contribution of electrically evoked dorsal root reflexes to peripheral vasodilatation and plasma extravasation. J Neuroinflammation 2011; 8:20. [PMID: 21356101 PMCID: PMC3058041 DOI: 10.1186/1742-2094-8-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 02/28/2011] [Indexed: 11/11/2022] Open
Abstract
Background Dorsal root reflexes (DRRs) are antidromic activities traveling along the primary afferent fibers, which can be generated by peripheral stimulation or central stimulation. DRRs are thought to be involved in the generation of neurogenic inflammation, as indicated by plasma extravasation and vasodilatation. The hypothesis of this study was that electrical stimulation of the central stump of a cut dorsal root would lead to generation of DRRs, resulting in plasma extravasation and vasodilatation. Methods Sprague-Dawley rats were prepared to expose spinal cord and L4-L6 dorsal roots under pentobarbital general anesthesia. Electrical stimulation of either intact, proximal or distal, cut dorsal roots was applied while plasma extravasation or blood perfusion of the hindpaw was recorded. Results While stimulation of the peripheral stump of a dorsal root elicited plasma extravasation, electrical stimulation of the central stump of a cut dorsal root generated significant DRRs, but failed to induce plasma extravasation. However, stimulation of the central stump induced a significant increase in blood perfusion. Conclusions It is suggested that DRRs are involved in vasodilatation but not plasma extravasation in neurogenic inflammation in normal animals.
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Affiliation(s)
- Oleg V Lobanov
- Department of Psychology, University of Texas at Arlington, Arlington, TX 76019, USA
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