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Yu Q, Cao W, Wang X, He W, Sun X, Chen L, Su Y, Zhang Z, Jing X. The Effect of Pre-Electroacupuncture on Nociceptive Discharges of Spinal Wide Dynamic Range Neurons in Rat. J Pain Res 2023; 16:695-706. [PMID: 36915279 PMCID: PMC10007980 DOI: 10.2147/jpr.s396481] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/21/2023] [Indexed: 03/09/2023] Open
Abstract
Purpose Spinal wide dynamic range (WDR) neurons are well studied in pain models and they play critical roles in regulating nociception. Evidence has started to accumulate that acupuncture produces a good analgesic effect via activating different primary fibers with distinct intensities. The purpose of the present study was to compare the distinct intensities of pre-electroacupuncture (pre-EA) at local muscular receptive fields (RFs), adjacent or contralateral non-RFs regulating the nociceptive discharges of spinal WDR neurons evoked by hypertonic saline (HS). Materials and Methods Spinal segments of electrophysiological recording were identified by neural tracers applied at the left gastrocnemius muscle. The thresholds of Aβ (TAβ), Aδ (TAδ) and C (TC) components of WDR neurons were measured to determine the intensity of pre-EA by extracellular recording. The discharges of WDR neurons induced by distinct intensities of pre-EA and 200 µL HS (6%) injection in left gastrocnemius muscle of rats were observed by extracellular recording. Results The spinal segments of WDR neurons were confirmed in lumbar (L)5-6 area according to the projective segments of dorsal root ganglion. TAβ, TAδ and TC of WDR neurons was determined to be 0.5, 1, and 2 mA, respectively. The pre-EA with intensities of TAβ (P < 0.05), TAδ (P < 0.05), TC (P < 0.05) or 2TC (P < 0.01) at ipsilateral adjacent non-RFs significantly reduced the discharges of WDR neurons, while at local RFs only pre-EA of TAδ (P < 0.05), TC (P < 0.05) and 2TC (P < 0.01) could inhibit the nociceptive discharges. In addition, intensity of pre-EA at contralateral non-RFs should reach at least TC to effectively inhibit the firing rates of WDR neurons (P < 0.01). Conclusion Pre-EA could suppress nociceptive discharges of WDR neurons and the inhibitory effects were dependent on the distinct intensities and locations of stimulation.
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Affiliation(s)
- Qingquan Yu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
| | - Wanying Cao
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
| | - Xiaoyu Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
| | - Wei He
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
| | - Xiaoyue Sun
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
| | - Lizhen Chen
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
| | - Yangshuai Su
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
| | - Zhiyun Zhang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
| | - Xianghong Jing
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China
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Valenzuela F, Rana M, Sitaram R, Uribe S, Eblen-Zajjur A. Non-Invasive Functional Evaluation of the Human Spinal Cord by Assessing the Peri-Spinal Neurovascular Network With Near Infrared Spectroscopy. IEEE Trans Neural Syst Rehabil Eng 2021; 29:2312-2321. [PMID: 34705650 DOI: 10.1109/tnsre.2021.3123587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Current medical care lacks an effective functional evaluation for the spinal cord. Magnetic resonance imaging and computed tomography mainly provide structural information of the spinal cord, while spinal somatosensory evoked potentials are limited by a low signal to noise ratio. We developed a non-invasive approach based on near-infrared spectroscopy in dual-wavelength (760 and 850 nm for deoxy- or oxyhemoglobin respectively) to record the neurovascular response (NVR) of the peri-spinal vascular network at the 7th cervical and 10th thoracic vertebral levels of the spinal cord, triggered by unilateral median nerve electrical stimulation (square pulse, 5-10 mA, 5 ms, 1 pulse every 4 minutes) at the wrist. Amplitude, rise-time, and duration of NVR were characterized in 20 healthy participants. A single, painless stimulus was able to elicit a high signal-to-noise ratio and multi-segmental NVR (mainly from Oxyhemoglobin) with a fast rise time of 6.18 [4.4-10.4] seconds (median [Percentile 25-75]) followed by a slow decay phase for about 30 seconds toward the baseline. Cervical NVR was earlier and larger than thoracic and no left/right asymmetry was detected. Stimulus intensity/NVR amplitude fitted to a 2nd order function. The characterization and feasibility of the peri-spinal NVR strongly support the potential clinical applications for a functional assessment of spinal cord lesions.
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Ramírez-Morales A, Hernández E, Rudomin P. Nociception induces a differential presynaptic modulation of the synaptic efficacy of nociceptive and proprioceptive joint afferents. Exp Brain Res 2021; 239:2375-2397. [PMID: 34101000 DOI: 10.1007/s00221-021-06140-6] [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: 09/26/2020] [Accepted: 05/22/2021] [Indexed: 11/25/2022]
Abstract
A previous study has indicated that during the state of central sensitization induced by the intradermic injection of capsaicin, there is a gradual facilitation of the dorsal horn neuronal responses produced by stimulation of the high-threshold articular afferents that is counteracted by a concurrent increase of descending inhibitory actions. Since these changes occurred without significantly affecting the responses produced by stimulation of the low-threshold articular afferents, it was suggested that the capsaicin-induced descending inhibition included a preferential presynaptic modulation of the synaptic efficacy of the slow conducting nociceptive joint afferents (Ramírez-Morales et al., Exp Brain Res 237:1629-1641, 2019). The present study was aimed to investigate more directly the contribution of presynaptic mechanisms in this descending control. We found that in the barbiturate anesthetized cat, stimulation of the high-threshold myelinated afferents in the posterior articular nerve (PAN) produces primary afferent hyperpolarization (PAH) in the slow conducting (25-35 m/s) and primary afferent depolarization (PAD) in the fast conducting (40-50 m/s) articular fibers. During the state of central sensitization induced by capsaicin, there is a supraspinally mediated shift of the autogenic PAH to PAD that takes place in the slow conducting fibers, basically without affecting the autogenic PAD generated in the fast conducting afferents. It is suggested that the change of presynaptic facilitation to presynaptic inhibition induced by capsaicin on the slow articular afferents is part of an homeostatic process aimed to keep the nociceptive-induced neuronal activity within manageable limits while preserving the proprioceptive information required for proper control of movement.
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Affiliation(s)
- A Ramírez-Morales
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - E Hernández
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - P Rudomin
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.
- El Colegio Nacional, Mexico City, Mexico.
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Qu Z, Liu L, Yang Y, Zhao L, Xu X, Li Z, Zhu Y, Jing X, Wang X, Zhang CS, Fisher M, Li B, Wang L. Electro-acupuncture inhibits C-fiber-evoked WDR neuronal activity of the trigeminocervical complex: Neurophysiological hypothesis of a complementary therapy for acute migraine modeled rats. Brain Res 2020; 1730:146670. [PMID: 31953213 DOI: 10.1016/j.brainres.2020.146670] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/07/2020] [Accepted: 01/11/2020] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Acupuncture has become a relevant complementary and alternative treatment for acute migraine; however, the neurophysiological mechanism (C-fibers) underlying this effect remains unclear. C-fibers play a crucial role for diffuse noxious inhibitory controls (DNIC) at wide dynamic range (WDR) neurons in the trigeminocervical complex (TCC) in migraine attacks, and we supposed that this may be the mechanism of acupuncture analgesia. This study aimed to examine the neurophysiology of acupuncture intervention in an acute migraine rat model. METHODS Inflammatory soup (IS) or saline was injected into the dura mater to establish a migraine and control model in rats. To explore the neurobiological mechanism of acupuncture for migraine, we implemented electro-acupuncture (EA), non-electric-stimulation acupuncture, and no-acupuncture in IS and saline injected rats, and recorded the single-cell extraneural neurophysiology of the atlas (C1) spinal dorsal horn neurons in the TCC. RESULTS Our research shows that electro-acupuncture at GB8 (Shuaigu), located in the periorbital region receptive field of the trigeminal nerve, may rapidly reduce the C-fiber evoked WDR neuronal discharges of the TCC within 60 s. DISCUSSION This study provides pioneering evidence of a potential neurobiological mechanism for the analgesic effect on migraine attacks achieved by electro-acupuncture intervention via DNIC. The data indicates that EA may become a crucial supplementary and alternative therapy for migraineurs that failed to respond to acute medications, e.g., fremanezumab, which achieves its analgesic effect via modulating Aσ-fibers, not C-fibers.
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Affiliation(s)
- Zhengyang Qu
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Lu Liu
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China; Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yi Yang
- Department of History, University College London, London, UK
| | - Luopeng Zhao
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China; Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Institute of Traditional Chinese Medicine, Beijing, China
| | - Xiaobai Xu
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Zhijuan Li
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Yupu Zhu
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Xianghong Jing
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaoyu Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Claire Shuiqing Zhang
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Marc Fisher
- Division of Stroke and Cerebrovascular Diseases, Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Bin Li
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Linpeng Wang
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China.
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Yu L, Wang W, Li L, Qin Q, Yu Y, Liu K, Zhao Y, Rong P, Zhu B. Inhibition of electroacupuncture on nociceptive responses of dorsal horn neurons evoked by noxious colorectal distention in an intensity-dependent manner. J Pain Res 2019; 12:231-242. [PMID: 30655692 PMCID: PMC6322705 DOI: 10.2147/jpr.s182876] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background The transmission of visceral nociception can be inhibited by electroacupuncture (EA) at the spinal level. However, relationships between current intensity and EA-induced analgesia are still lacking. This study compares the effects of different intensities of EA at local acupoints and heterotopic acupoints on nociceptive responses of spinal wide dynamic range (WDR) neurons induced by noxious colorectal distension (CRD). Materials and methods Experiments were conducted on 40 Sprague Dawley rats anesthetized with 10% urethane. Discharges of WDR neurons in the L1–L3 segments of the dorsal horn of the spinal cord were recorded extracellularly by glass micropipettes. Different intensities of EA (0.5, 1, 2, 4, 6, and 8 mA, 0.5 ms, 2 Hz) were applied to contralateral “Zusanli” (ST 36) or “Neiguan” (PC 6), with either the same or different segmental innervation of the colon. Results In local acupoints, the increased discharges of WDR neurons evoked by CRD were significantly inhibited by EA at 0.5–8 mA. A positive relationship between current intensity and the inhibiting rate was observed within 0.5–4 mA, but the inhibiting rate reached a plateau when EA exceeded 4 mA. In heterotopic acupoints, the increased discharges of WDR neurons evoked by CRD were significantly inhibited by EA at 2–8 mA. A positive relationship between current intensity and the inhibiting rate was observed within 2–6 mA. Further increase in the current beyond 6 mA also resulted in a plateau effect. Conclusion Within a certain range, the nociceptive responses of dorsal horn neurons induced by CRD could be inhibited by EA in an intensity-dependent manner.
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Affiliation(s)
- Lingling Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.,Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China, ;
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Liang Li
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China, ;
| | - Qingguang Qin
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China, ;
| | - Yutian Yu
- 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, ;
| | - Yufeng Zhao
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China, ;
| | - Peijing Rong
- 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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Meléndez-Gallardo J, Eblen-Zajjur A. Thermo-dependence of noxious mechanical heterotopic stimulation-dependent modulation of the spinal dorsal horn response to somatosensory stimulation. J Integr Neurosci 2018; 17:413-424. [PMID: 29562550 DOI: 10.3233/jin-180076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Despite the frequent clinical hyper- or hypothermia cases, thermal-dependence of the endogenous pain modulation system at the spinal cord is not well understood. We evaluate spinal dorsal horn neuronal network responses during mechanical heterotopic noxious stimuli (HNS) at three different body temperatures (34; 37 or 40°C) by measuring lumbar cord dorsum potentials activated by electrical stimulation of the ipsilateral sural nerve in adult thiopental anesthetized rats. A noxious clamp was applied randomly to the tail, right hindpaw, right forepaw, muzzle and left forepaw. HNS induced a decrease of the N wave amplitude and duration at 37°C. This effect was reduced at 40°C for both amplitude (-18.2% for 37-40°C; P<0.0005) and duration (-16.4% for 37-40°C; P<0.0001). P wave did not show neither amplitude nor duration changes at neither 3 tested temperatures. Clinical range changes of temperature could modify pain sensation, moreover, hyperthermia increases nociceptive sensory input to dorsal horn, and could exacerbate pain sensation in individuals with fever.
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Affiliation(s)
- J Meléndez-Gallardo
- Centro de Biofísica y Bioquímica del Instituto Venezolano de Investigaciones Científicas, IVIC, Caracas, Venezuela.,Centro de Biofísica y Neurociencias, CBN-UC, Facultad de Ciencias de la Salud, Universidad de Carabobo, Valencia, Venezuela
| | - A Eblen-Zajjur
- Centro de Biofísica y Neurociencias, CBN-UC, Facultad de Ciencias de la Salud, Universidad de Carabobo, Valencia, Venezuela.,Instituto de Ingeniería Biológica y Médica, Facultades de Ingeniería, Medicina y Biología, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, P.O. 7820436, Santiago de Chile, Chile
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