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Persistent muscle hyperalgesia after adolescent stress is exacerbated by a mild-nociceptive input in adulthood and is associated with microglia activation. Sci Rep 2022; 12:18324. [PMID: 36316425 PMCID: PMC9622712 DOI: 10.1038/s41598-022-21808-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/04/2022] [Indexed: 11/07/2022] Open
Abstract
Non-specific low back pain (LBP) is a major global disease burden and childhood adversity predisposes to its development. The mechanisms are largely unknown. Here, we investigated if adversity in young rats augments mechanical hyperalgesia and how spinal cord microglia contribute to this. Adolescent rats underwent restraint stress, control animals were handled. In adulthood, all rats received two intramuscular injections of NGF/saline or both into the lumbar multifidus muscle. Stress induced in rats at adolescence lowered low back pressure pain threshold (PPT; p = 0.0001) and paw withdrawal threshold (PWT; p = 0.0007). The lowered muscle PPT persisted throughout adulthood (p = 0.012). A subsequent NGF in adulthood lowered only PPT (d = 0.87). Immunohistochemistry revealed changes in microglia morphology: stress followed by NGF induced a significant increase in ameboid state (p < 0.05). Repeated NGF injections without stress showed significantly increased cell size in surveilling and bushy states (p < 0.05). Thus, stress in adolescence induced persistent muscle hyperalgesia that can be enhanced by a mild-nociceptive input. The accompanying morphological changes in microglia differ between priming by adolescent stress and by nociceptive inputs. This novel rodent model shows that adolescent stress is a risk factor for the development of LBP in adulthood and that morphological changes in microglia are signs of spinal mechanisms involved.
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Duan-Mu CL, Zhang XN, Shi H, Su YS, Wan HY, Wang Y, Qu ZY, He W, Wang XY, Jing XH. Electroacupuncture-Induced Muscular Inflammatory Pain Relief Was Associated With Activation of Low-Threshold Mechanoreceptor Neurons and Inhibition of Wide Dynamic Range Neurons in Spinal Dorsal Horn. Front Neurosci 2021; 15:687173. [PMID: 34305519 PMCID: PMC8295590 DOI: 10.3389/fnins.2021.687173] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/04/2021] [Indexed: 12/29/2022] Open
Abstract
Acupuncture is an effective alternative therapy for pain management. Evidence suggests that acupuncture relieves pain by exciting somatic afferent nerve fibers. However, the mechanism underlying the interaction between neurons in different layers of the spinal dorsal horn induced by electroacupuncture (EA) remains unclear. The aim of this study was to explore the mechanism of EA relieving inflammatory muscle pain, which was associated with activation of the spontaneous firing of low-threshold mechanoreceptor (LTM) neurons and inhibition of wide dynamic range (WDR) neuronal activities in the spinal dorsal horn of rats. Inflammatory muscle pain was induced by injecting complete Freund’s adjuvant into the right biceps femoris muscle. EA with intensity of threshold of A fibers (Ta) in Liangqiu (ST34) muscle considerably inhibited the abnormal spontaneous activities of electromyography (EMG) due to muscle inflammation. While EA with intensity of C-fiber threshold (Tc) increased the abnormal activities of EMG. EA with Ta also ameliorated the imbalance of weight-bearing behavior. A microelectrode array with 750-μm depth covering 32 channels was used to record the neuronal activities of WDR and LTM in different layers of the spinal dorsal horn. The spontaneous firing of LTM neurons was enhanced by EA-Ta, while the spontaneous firing of WDR neurons was inhibited. Moreover, EA-Ta led to a significant inverse correlation between changes in the frequency of WDR and LTM neurons (r = −0.64, p < 0.05). In conclusion, the results indicated that EA could alleviate inflammatory muscle pain, which was associated with facilitation of the spontaneous firing of LTM neurons and inhibition of WDR neuronal activities. This provides a promising evidence that EA-Ta could be applied to relieve muscular inflammatory pain in clinical practice.
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Affiliation(s)
- Cheng-Lin Duan-Mu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiao-Ning Zhang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hong Shi
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yang-Shuai Su
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hong-Ye Wan
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yi Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zheng-Yang Qu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Wei He
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiao-Yu Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiang-Hong Jing
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
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Rat dorsal horn neurons primed by stress develop a long-lasting manifest sensitization after a short-lasting nociceptive low back input. Pain Rep 2021; 6:e904. [PMID: 33688602 PMCID: PMC7935483 DOI: 10.1097/pr9.0000000000000904] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/29/2020] [Accepted: 01/15/2021] [Indexed: 11/26/2022] Open
Abstract
Background A single injection of nerve growth factor (NGF) into a low back muscle induces a latent sensitization of rat dorsal horn neurons (DHNs) that primes for a manifest sensitization by a subsequent second NGF injection. Repeated restraint stress also causes a latent DHN sensitization. Objective In this study, we investigated whether repeated restraint stress followed by a single NGF injection causes a manifest sensitization of DHNs. Methods Rats were stressed repeatedly in a narrow plastic restrainer (1 hour on 12 consecutive days). Control animals were handled but not restrained. Two days after stress paradigm, behavioral tests and electrophysiological in vivo recordings from single DHNs were performed. Mild nociceptive low back input was induced by a single NGF injection into the lumbar multifidus muscle just before the recording started. Results Restraint stress slightly lowered the low back pressure pain threshold (Cohen d = 0.83). Subsequent NGF injection increased the proportion of neurons responsive to deep low back input (control + NGF: 14%, stress + NGF: 39%; P = 0.041), mostly for neurons with input from outside the low back (7% vs 26%; P = 0.081). There was an increased proportion of neurons with resting activity (28% vs 55%; P = 0.039), especially in neurons having deep input (0% vs 26%; P = 0.004). Conclusions The results indicate that stress followed by a short-lasting nociceptive input causes manifest sensitization of DHNs to deep input, mainly from tissue outside the low back associated with an increased resting activity. These findings on neuronal mechanisms in our rodent model suggest how stress might predispose to radiating pain in patients.
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Sessler K, Blechschmidt V, Hoheisel U, Mense S, Schirmer L, Treede RD. Spinal cord fractalkine (CX3CL1) signaling is critical for neuronal sensitization in experimental nonspecific, myofascial low back pain. J Neurophysiol 2021; 125:1598-1611. [PMID: 33596743 DOI: 10.1152/jn.00348.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Neuroactive substances released by activated microglia contribute to hyperexcitability of spinal dorsal horn neurons in many animal models of chronic pain. An important feedback loop mechanism is via release of fractalkine (CX3CL1) from primary afferent terminals and dorsal horn neurons and binding to CX3CR1 receptors on microglial cells. We studied the involvement of fractalkine signaling in latent and manifest spinal sensitization induced by two injections of nerve growth factor (NGF) into the lumbar multifidus muscle as a model for myofascial low back pain. Single dorsal horn neurons were recorded in vivo to study their receptive fields and spontaneous activity. Under intrathecal vehicle application, the two NGF injections led to an increased proportion of neurons responding to stimulation of deep tissues (41%), to receptive field expansion into the hindlimb (15%), and to resting activity (53%). Blocking fractalkine signaling by continuous intrathecal administration of neutralizing antibodies completely prevented these signs of spinal sensitization to a similar extent as in a previous study with the microglia inhibitor minocycline. Reversely, fractalkine itself induced similar sensitization in a dose-dependent manner (for 200 ng/mL: 45% deep tissue responses, 24% receptive field expansion, and 45% resting activity) as repeated nociceptive stimulation by intramuscular NGF injections. A subsequent single NGF injection did not have an additive effect. Our data suggest that neuron-to-microglia signaling via the CX3CL1-CX3CR1 pathway is critically involved in the initiation of nonspecific, myofascial low back pain through repetitive nociceptive stimuli.NEW & NOTEWORTHY Blocking fractalkine signaling by neutralizing antibodies completely prevented spinal sensitization induced by repetitive mild nociceptive input [2 nerve growth factor (NGF) injections into the multifidus muscle] Conversely, fractalkine given intrathecally caused the same pattern of spinal sensitization as the nociceptive NGF injections. Fractalkine signaling is critically involved in sensitization of dorsal horn neurons induced by repeated nociceptive low back muscle stimulation and may hence be a potential target for the prevention of nonspecific, myofascial low back pain.
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Affiliation(s)
- Katharina Sessler
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Vivian Blechschmidt
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Ulrich Hoheisel
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Siegfried Mense
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Lucas Schirmer
- Department of Neurology, Mannheim Center for Translational Neurosciences, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Wang T, Vahdatinia R, Humbert S, Stecco A. Myofascial Injection Using Fascial Layer-Specific Hydromanipulation Technique (FLuSH) and the Delineation of Multifactorial Myofascial Pain. MEDICINA (KAUNAS, LITHUANIA) 2020; 56:medicina56120717. [PMID: 33419263 PMCID: PMC7766734 DOI: 10.3390/medicina56120717] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/09/2020] [Accepted: 12/18/2020] [Indexed: 12/16/2022]
Abstract
Background and objectives: The aims of this study were to delineate the contribution of specific fascial layers of the myofascial unit to myofascial pain and introduce the use of ultrasound-guided fascial layer-specific hydromanipulation (FLuSH) as a novel technique in the treatment of myofascial pain. Materials and Methods: The clinical data of 20 consecutive adult patients who underwent myofascial injections using FLuSH technique for the treatment of myofascial pain were reviewed. The FLuSH technique involved measuring the pain pressure threshold using an analog algometer initially and after each ultrasound guided injection of normal saline into the specific layers of the myofascial unit (superficial fascia, deep fascia, or muscle) in myofascial points corresponding with Centers of Coordination/Fusion (Fascial Manipulation®). The outcome measured was the change in pain pressure threshold after injection of each specific fascial layer. Results: Deep fascia was involved in 73%, superficial fascia in 55%, and muscle in 43% of points. A non-response to treatment of all three layers occurred in 10% of all injected points. The most common combinations of fascial layer involvement were deep fascia alone in 23%, deep fascia and superficial fascia in 22%, and deep fascia and muscle in 18% of injected points. Each individual had on average of 3.0 ± 1.2 different combinations of fascial layers contributing to myofascial pain. Conclusions: The data support the hypothesis that multiple fascial layers are responsible for myofascial pain. In particular, for a given patient, pain may develop from discrete combinations of fascial layers unique to each myofascial point. Non-response to treatment of the myofascial unit may represent a centralized pain process. Adequate treatment of myofascial pain may require treatment of each point as a distinct pathologic entity rather than uniformly in a given patient or across patients.
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Affiliation(s)
- Tina Wang
- School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA; (R.V.); (S.H.)
- Correspondence:
| | - Roya Vahdatinia
- School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA; (R.V.); (S.H.)
| | - Sarah Humbert
- School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA; (R.V.); (S.H.)
| | - Antonio Stecco
- Department of Rehabilitation Medicine, Grossman School of Medicine, New York University, New York, NY 10016, USA;
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Alteration in REM sleep and sleep spindles’ characteristics by a model of immobilization stress in rat. Sleep Biol Rhythms 2020. [DOI: 10.1007/s41105-020-00263-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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8
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Wettstein M, Eich W, Bieber C, Tesarz J. Profiles of Subjective Well-being in Patients with Chronic Back Pain: Contrasting Subjective and Objective Correlates. PAIN MEDICINE 2019; 20:668-680. [PMID: 30272221 DOI: 10.1093/pm/pny162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The detrimental impact of nonspecific chronic low back pain (CLBP) on quality of life is well known. However, patients with CLBP represent a remarkably heterogeneous group, and not all of them report compromised well-being. METHODS In this study, we investigated this heterogeneity by identifying profiles (or clusters) of well-being and their correlates in 239 CLBP patients. To take the multidimensionality of subjective well-being into account, we included multiple well-being indicators (depression, anxiety, affective distress, perceived control over life). For an in-depth characterization of the well-being profiles, we assessed 1) sociodemographic indicators (age, gender, education, marital status, occupational status), 2) pain-related measures (pain intensity, subjective and objective pain disability, number of pain locations), 3) psychosocial resources (mental health, resilience, perceived support), 4) biographical factors (trauma), and 5) somatosensory profiles based on quantitative sensory testing. RESULTS Based on two-step cluster analysis, we identified three distinct well-being profiles, characterized by either generally high well-being (cluster 1, n = 51), moderate well-being (cluster 2, n = 104), or consistently low well-being (cluster 3, n = 77), respectively. Most differences between the derived well-being profiles regarding sociodemographic, psychosocial, and biographical measures were of weak to moderate effect size. Larger effect sizes were observed for differences in pain intensity and subjective, but not objective, pain disability. Finally, the largest effects were found for differences in psychosocial resources. CONCLUSIONS Our findings suggest that not only in nonclinical samples, but also in patients with chronic pain, well-being is more closely associated with psychological resources and subjective evaluations than with objective parameters.
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Affiliation(s)
- Markus Wettstein
- Department of General Internal Medicine and Psychosomatics, Medical Hospital, Heidelberg University, Heidelberg, Germany.,German Centre of Gerontology, Berlin, Germany
| | - Wolfgang Eich
- Department of General Internal Medicine and Psychosomatics, Medical Hospital, Heidelberg University, Heidelberg, Germany
| | - Christiane Bieber
- Department of General Internal Medicine and Psychosomatics, Medical Hospital, Heidelberg University, Heidelberg, Germany
| | - Jonas Tesarz
- Department of General Internal Medicine and Psychosomatics, Medical Hospital, Heidelberg University, Heidelberg, Germany
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9
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Abstract
Adult pain perception is influenced substantially by interactions between mind, body, and social environment during early life. Early stress exposure and traumatic life events induce powerful psychophysical stress reactions that exert multiple neurofunctional processes. This has significant implications for pain perception and pain processing. As part of this review, the complex relationships between traumatic stress experiences and associated psychobiological mechanisms of chronic pain will be discussed. Based on selected studies, psychophysiological findings are presented and possible underlying mechanisms are discussed. The article concludes with a discussion of potential implications for treatment.
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10
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de Azambuja G, Hortscht U, Hoheisel U, Oliveira Fusaro MC, Mense S, Treede RD. Short-term swimming exercise attenuates the sensitization of dorsal horn neurons in rats with NGF-induced low back pain. Eur J Pain 2018; 22:1409-1418. [PMID: 29635722 DOI: 10.1002/ejp.1230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2018] [Indexed: 01/25/2023]
Abstract
BACKGROUND Physical exercise has been shown to be an effective therapy for non-specific low back pain. The study investigated if swimming exercise is a means to reduce the spinal sensitization in an animal model of non-specific low back pain. METHODS In deeply anesthetized rats, dorsal horn neurons were recorded in spinal segment L2. To induce sensitization of dorsal horn neurons, two injections of nerve growth factor were made into the lumbar multifidus muscle at an interval of 5 days. Swimming exercise for 30 min was performed on the 5 days between both NGF injections. A control group received the NGF injections without exercise treatment. RESULTS Swimming exercise caused a significant decrease in the NGF-induced hyperexcitability of dorsal horn neurons. Compared to control, the proportion of neurons with input from deep somatic tissues and of convergent neurons with input from at least two types of different tissues decreased significantly (50% vs. 25% and 37% vs. 15%; both p < 0.05). Swimming exercise also reduced the NGF-induced increase in neuronal resting activity. Both the proportion of active neurons and the mean discharge frequency of all neurons decreased significantly (60%, 76.3 ± 23.1 imp/min; vs. 25%, 51.7 ± 35.1 imp/min; both p < 0.01). CONCLUSIONS In our animal model of low back pain, short-term swimming exercise effectively reduced the latent sensitization of spinal dorsal horn neurons. Swimming exercise decreased the hyperexcitability of the neurons to low back input and lowered the resting activity of sensitized neurons. SIGNIFICANCE Physical exercise is a common treatment for low back pain. The possible mechanisms underlying the effects of exercise are probably multifold. This work shows that swimming exercise prevents sensitization of dorsal horn neurons, which may be one mechanism for the positive effects of exercise.
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Affiliation(s)
- G de Azambuja
- Department of Neurophysiology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Laboratory of Pain and Inflammation Research, School of Applied Sciences, State University of Campinas, Limeira, Brazil
| | - U Hortscht
- Department of Neurophysiology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - U Hoheisel
- Department of Neurophysiology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - M C Oliveira Fusaro
- Laboratory of Pain and Inflammation Research, School of Applied Sciences, State University of Campinas, Limeira, Brazil
| | - S Mense
- Department of Neurophysiology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - R-D Treede
- Department of Neurophysiology, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Herzog JI, Schmahl C. Adverse Childhood Experiences and the Consequences on Neurobiological, Psychosocial, and Somatic Conditions Across the Lifespan. Front Psychiatry 2018; 9:420. [PMID: 30233435 PMCID: PMC6131660 DOI: 10.3389/fpsyt.2018.00420] [Citation(s) in RCA: 257] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 08/15/2018] [Indexed: 01/08/2023] Open
Abstract
Introduction: Adverse childhood experiences (ACE) such as sexual and physical abuse or neglect are frequent in childhood and constitute a massive stressor with long-lasting adverse effects on the brain, mental and physical health.The aim of this qualitative review is to present a concise overview of the present literature on the impact of ACE on neurobiology, mental and somatic health in later adulthood. Methods: The authors reviewed the existing literature on the impact of ACE on neurobiology, mental and somatic health in later adulthood and summarized the results for a concise qualitative overview. Results: In adulthood, the history of ACE can result in complex clinical profiles with several co-occurring mental and somatic disorders such as posttraumatic stress disorder, depression, borderline personality disorder, obesity and diabetes. Although a general stress effect in the development of the disorders and neural alterations can be assumed, the role of type and timing of ACE is of particular interest in terms of prevention and treatment of ACE-related mental and somatic conditions. It has been suggested that during certain vulnerable developmental phases the risk for subsequent ACE-related disorders is increased. Moreover, emerging evidence points to sensitive periods and specificity of ACE-subtypes in the development of neurobiological alterations, e.g., volumetric and functional changes in the amygdala and hippocampus. Conclusion: Longitudinal studies are needed to investigate complex ACE-related characteristics and mechanisms relevant for mental and somatic disorders by integrating state of the art knowledge and methods. By identifying and validating psychosocial and somatic risk factors and diagnostic markers one might improve the development of innovative somatic and psychological treatment options for individuals suffering from ACE-related disorders.
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Affiliation(s)
- Julia I Herzog
- Department of Psychosomatic Medicine and Psychotherapy, Central Institute of Mental Health Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Christian Schmahl
- Department of Psychosomatic Medicine and Psychotherapy, Central Institute of Mental Health Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Department of Psychiatry, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
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12
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Zhang J, Mense S, Treede RD, Hoheisel U. Prevention and reversal of latent sensitization of dorsal horn neurons by glial blockers in a model of low back pain in male rats. J Neurophysiol 2017; 118:2059-2069. [PMID: 28615336 DOI: 10.1152/jn.00680.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 12/13/2022] Open
Abstract
In an animal model of nonspecific low back pain, recordings from dorsal horn neurons were made to investigate the influence of glial cells in the central sensitization process. To induce a latent sensitization of the neurons, nerve growth factor (NGF) was injected into the multifidus muscle; the manifest sensitization to a second NGF injection 5 days later was used as a read-out. The sensitization manifested in increased resting activity and in an increased proportion of neurons responding to stimulation of deep somatic tissues. To block microglial activation, minocycline was continuously administered intrathecally starting 1 day before or 2 days after the first NGF injection. The glia inhibitor fluorocitrate that also blocks astrocyte activation was administrated 2 days after the first injection. Minocycline applied before the first NGF injection reduced the manifest sensitization after the second NGF injection to control values. The proportion of neurons responsive to stimulation of deep tissues was reduced from 50% to 17.7% (P < 0.01). No significant changes occurred when minocycline was applied after the first injection. In contrast, fluorocitrate administrated after the first NGF injection reduced significantly the proportion of neurons with deep input (15.8%, P < 0.01). A block of glia activation had no significant effect on the increased resting activity. The data suggest that blocking microglial activation prevented the NGF-induced latent spinal sensitization, whereas blocking astrocyte activation reversed it. The induction of spinal neuronal sensitization in this pain model appears to depend on microglia activation, whereas its maintenance is regulated by activated astrocytes.NEW & NOTEWORTHY Activated microglia and astrocytes mediate the latent sensitization induced by nerve growth factor in dorsal horn neurons that receive input from deep tissues of the low back. These processes may contribute to nonspecific low back pain.
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Affiliation(s)
- Juanjuan Zhang
- Chair of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany; and.,Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Siegfried Mense
- Chair of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany; and
| | - Rolf-Detlef Treede
- Chair of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany; and
| | - Ulrich Hoheisel
- Chair of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany; and
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14
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Abstract
Pain research is based broadly on physiological disciplines and its development follows the methodological progress of the era, from classical psychophysiology to electrophysiological investigations at peripheral and central nociceptive systems, single cells and ion channels to modern imaging of nociceptive processing. Physiological pain research in Germany has long been part of an interdisciplinary research network extending beyond all political boundaries, and this situation has continued since molecular techniques started to dominate all biomedical research. Current scientific questions, such as intracellular nociceptive signal mechanisms, interactions with other physiological systems including the immune system, or the genetic basis of epidemic and chronic pain diseases can only be solved interdisciplinary and with international collaboration.
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Affiliation(s)
- K Messlinger
- Institut für Physiologie und Pathophysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 17, 91054, Erlangen, Deutschland.
| | - H O Handwerker
- Institut für Physiologie und Pathophysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 17, 91054, Erlangen, Deutschland
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Hansen AE, Marcus NJ. Is It Time to Consider Soft Tissue as a Pain Generator in Nonspecific Low Back Pain? PAIN MEDICINE 2016; 17:1969-1970. [PMID: 27570247 DOI: 10.1093/pm/pnw204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ann E Hansen
- *Department of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Boise Veterans Affairs Medical Center, Boise, Idaho
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Altered pressure pain thresholds and increased wind-up in adult patients with chronic back pain with a history of childhood maltreatment: a quantitative sensory testing study. Pain 2016; 157:1799-1809. [DOI: 10.1097/j.pain.0000000000000586] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Affiliation(s)
- W Jänig
- Physiologisches Institut, Christian-Albrechts-Universität zu Kiel, Germany
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