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Grau JW, Hudson KE, Johnston DT, Partipilo SR. Updating perspectives on spinal cord function: motor coordination, timing, relational processing, and memory below the brain. Front Syst Neurosci 2024; 18:1184597. [PMID: 38444825 PMCID: PMC10912355 DOI: 10.3389/fnsys.2024.1184597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 01/29/2024] [Indexed: 03/07/2024] Open
Abstract
Those studying neural systems within the brain have historically assumed that lower-level processes in the spinal cord act in a mechanical manner, to relay afferent signals and execute motor commands. From this view, abstracting temporal and environmental relations is the province of the brain. Here we review work conducted over the last 50 years that challenges this perspective, demonstrating that mechanisms within the spinal cord can organize coordinated behavior (stepping), induce a lasting change in how pain (nociceptive) signals are processed, abstract stimulus-stimulus (Pavlovian) and response-outcome (instrumental) relations, and infer whether stimuli occur in a random or regular manner. The mechanisms that underlie these processes depend upon signal pathways (e.g., NMDA receptor mediated plasticity) analogous to those implicated in brain-dependent learning and memory. New data show that spinal cord injury (SCI) can enable plasticity within the spinal cord by reducing the inhibitory effect of GABA. It is suggested that the signals relayed to the brain may contain information about environmental relations and that spinal cord systems can coordinate action in response to descending signals from the brain. We further suggest that the study of stimulus processing, learning, memory, and cognitive-like processing in the spinal cord can inform our views of brain function, providing an attractive model system. Most importantly, the work has revealed new avenues of treatment for those that have suffered a SCI.
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Affiliation(s)
- James W. Grau
- Lab of Dr. James Grau, Department of Psychological and Brain Sciences, Cellular and Behavioral Neuroscience, Texas A&M University, College Station, TX, United States
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Mandloi S, Syed M, Ailes I, Shoraka O, Leiby B, Miao J, Thalheimer S, Heller J, Mohamed FB, Sharan A, Harrop J, Krisa L, Alizadeh M. Exploring Functional Connectivity in Chronic Spinal Cord Injury Patients With Neuropathic Pain Versus Without Neuropathic Pain. Neurotrauma Rep 2024; 5:16-27. [PMID: 38249324 PMCID: PMC10797176 DOI: 10.1089/neur.2023.0070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024] Open
Abstract
The great majority of spinal cord injury (SCI) patients have debilitating chronic pain. Despite decades of research, these pain pathways of neuropathic pain (NP) are unknown. SCI patients have been shown to have abnormal brain pain pathways. We hypothesize that SCI NP patients' pain matrix is altered compared to SCI patients without NP. This study examines the functional connectivity (FC) in SCI patients with moderate-severe chronic NP compared to SCI patients with mild-no NP. These groups were compared to control subjects. The Neuropathic Pain Questionnaire and neurological evaluation based on the International Standard Neurological Classification of SCI were utilized to define the severity and level of injury. Of the 10 SCI patients, 7 (48.6 ± 17.02 years old, 6 male and 1 female) indicated that they had NP and 3 did not have NP (39.33 ± 8.08 years old, 2 male and 1 female). Ten uninjured neurologically intact participants were used as controls (24.8 ± 4.61 years old, 5 male and 5 female). FC metrics were obtained from the comparisons of resting-state functional magnetic resonance imaging among our various groups (controls, SCI with NP, and SCI without NP). For each comparison, a region-of-interest (ROI)-to-ROI connectivity analysis was pursued, encompassing a total of 175 ROIs based on a customized atlas derived from the AAL3 atlas. The analysis accounted for covariates such as age and sex. To correct for multiple comparisons, a strict Bonferroni correction was applied with a significance level of p < 0.05/NROIs. When comparing SCI patients with moderate-to-severe pain to those with mild-to-no pain, specific thalamic nuclei had altered connections. These nuclei included: medial pulvinar; lateral pulvinar; medial geniculate nucleus; lateral geniculate nucleus; and mediodorsal magnocellular nucleus. There was increased FC between the lateral geniculate nucleus and the anteroventral nucleus in NP post-SCI. Our analysis additionally highlights the relationships between the frontal lobe and temporal lobe with pain. This study successfully identifies thalamic neuroplastic changes that occur in patients with SCI who develop NP. It additionally underscores the pain matrix and involvement of the frontal and temporal lobes as well. Our findings complement that the development of NP post-SCI involves cognitive, emotional, and behavioral influences.
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Affiliation(s)
- Shreya Mandloi
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mashaal Syed
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Isaiah Ailes
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Omid Shoraka
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Benjamin Leiby
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jingya Miao
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Sara Thalheimer
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Joshua Heller
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Feroze B. Mohamed
- Thomas Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ashwini Sharan
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - James Harrop
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Laura Krisa
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mahdi Alizadeh
- Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
- Thomas Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Tadege G, Sirak B, Abebe D, Nureye D. Antinociceptive and antiinflammatory activities of crude leave extract and solvent fractions of Commelina latifolia Hochst. ex C.B.Clarke (Commelinaceae) leaves in murine model. Front Pharmacol 2023; 14:1284087. [PMID: 38130405 PMCID: PMC10733449 DOI: 10.3389/fphar.2023.1284087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 11/29/2023] [Indexed: 12/23/2023] Open
Abstract
Ethnopharmacological relevance: In the past, Ethiopian traditional medicine employed the leaves of the native Commelina latifolia Hochst. ex C.B. Clarke plant to treat wounds, pain, and malaria. Aim of the study: The crude extract and solvent fractions of C. latifolia Hochst. ex C.B. Clarke leaves were examined in the present investigation to determine their ability to have an antiinflammatory effect and provide an antinociceptive effect in animal models. Materials and methods: The leaves of C. latifolia were extracted with 80% methanol, and the CL crude extract was further fractionated with chloroform, pure methanol, and distilled water. The carrageenan-induced paw edema model was used to test the extracts' ability to reduce inflammation. The hotplate model and the acetic acid-induced writhing test on rodents were used to test the extracts' potential antinociceptive effect to reduce pain. Results: Inflammation was decreased by 64.59% with CL crude extract (400 mg/kg); 56.34% (400 mg/kg) of methanol fraction, 64.59% of aqueous fraction (400 mg/kg), and 38.27% of chloroform fraction in the carrageenan-induced inflammatory model. All extracts demonstrated a considerable lengthening of the nociception reaction time in the hot plate test, with a maximum antinociceptive effect of 78.98% (crude extract) and 71.65% (solvent fractions). At a dosage of 400 mg/kg, the natural C. latifolia crude extract and aqueous fraction demonstrated considerable antinociceptive effects against acetylsalicylic acid (ASA) during the writhing test (48.83% and 45.37than%, respectively). The current findings support Ethiopia's traditional user's assertions that the herb can alleviate inflammation and pain.
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Affiliation(s)
- Getnet Tadege
- Department of Pharmacy, College of Health Sciences, Debre Markos University, Debre Marqos, Ethiopia
| | - Betelhem Sirak
- Department of Pharmacy, College of Medicine Health Sciences, Arbaminch University, Arba Minch, Ethiopia
| | - Dehnnet Abebe
- Department of Pharmacy, College of Health Sciences, Debre Markos University, Debre Marqos, Ethiopia
| | - Dejen Nureye
- School of Pharmacy, Institute of Health, Jimma University, Jimma, Oromia, Ethiopia
- School of Pharmacy, College of Medicine and Health Sciences, Mizan-Tepi University, Mizan-Aman, Ethiopia
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Dorton MC, Kramer JK, de Groot S, Post MWM, Claydon VE. Relationships between cardiovascular disease risk, neuropathic pain, mental health, and autonomic function in chronic spinal cord injury. Spinal Cord 2023; 61:548-555. [PMID: 37749189 DOI: 10.1038/s41393-023-00933-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 08/28/2023] [Accepted: 09/06/2023] [Indexed: 09/27/2023]
Abstract
STUDY DESIGN Multicentre, cross-sectional study. OBJECTIVES To determine if clinical measures of poor mental health (MH-) and neuropathic pain (NP) are related to increased CVD risk in individuals with chronic spinal cord injury (SCI), and further elucidate the relationships between CVD risk, autonomic function, NP, and MH-. SETTING Eight SCI rehabilitation centres in the Netherlands. METHODS Individuals (n = 257) with a traumatic, chronic (≥10 yrs) SCI, with age at injury between 18-35 years, completed a self-report questionnaire and a one-day visit to a rehabilitation centre for testing. CVD risk was calculated using Framingham risk score. NP was inferred using The Douleur Neuropathique 4 clinical examination, and MH- was assessed using the five-item Mental Health Inventory questionnaire. Cardiovascular autonomic function was determined from peak heart rate during maximal exercise (HRpeak). RESULTS There was a high prevalence of both NP (39%) and MH- (45%) following SCI. MH- was significantly correlated with an adverse CVD risk profile (r = 0.174; p = 0.01), increased the odds of adverse 30-year CVD risk by 2.2 (CI 0.92-2.81, p = 0.02), and is an important variable in determining CVD risk (importance=0.74, p = 0.05). Females (p = 0.05) and those with a higher HRpeak (p = 0.046) tended to be more likely to have NP. CONCLUSIONS Clinical measures of MH-, but not NP, are important factors for increased CVD risk following SCI. NP tended to be more prevalent in those with more preserved cardiovascular autonomic function. The interrelationships between secondary consequences of SCI are complex and need further exploration.
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Affiliation(s)
- Matthew C Dorton
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- International Collaboration on Repair and Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
| | - John K Kramer
- International Collaboration on Repair and Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
| | - Sonja de Groot
- Amsterdam Rehabilitation Research Center, Reade, Amsterdam, The Netherlands
- University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, The Netherlands
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Marcel W M Post
- Center of Excellence in Rehabilitation Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, and de Hoogstraat Rehabilitation, Utrecht, The Netherlands
- University of Groningen, University Medical Center Groningen, Center for Rehabilitation, Department of Rehabilitation Medicine, Groningen, The Netherlands
| | - Victoria E Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
- International Collaboration on Repair and Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada.
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Furlan JC, Loh E, Boulos MI. The potential effects of untreated sleep-related breathing disorders on neuropathic pain, spasticity, and cardiovascular dysfunction following spinal cord injury: A cross-sectional prospective study protocol. PLoS One 2023; 18:e0282860. [PMID: 37130111 PMCID: PMC10153696 DOI: 10.1371/journal.pone.0282860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 02/13/2023] [Indexed: 05/03/2023] Open
Abstract
INTRODUCTION Sleep-related breathing disorders (SRBDs), neuropathic pain, spasticity and cardiovascular autonomic dysfunction are common after spinal cord injury (SCI). Prior studies suggest that systemic inflammation following SCI may be implicated in the development of neuropathic pain, spasticity and cardiovascular dysfunction. Given that SRBDs also cause a systemic inflammatory response, we hypothesized that individuals with SCI who develop more severe SRBDs would experience more intense neuropathic pain, more severe spasticity and more significant cardiovascular autonomic dysfunction. METHODS This cross-sectional prospective study will explore the previously understudied hypothesis that SRBDs are associated with increased neuropathic pain, spasticity, and cardiovascular autonomic dysfunction in adult individuals with low-cervical/high-thoracic (injury level at C5 to T6), complete/incomplete (ASIA Impairment Scale A, B, C or D) SCI. DISCUSSION To our knowledge, no prior study has addressed this clinically relevant question on whether the degree of SRBDs affects the intensity of neuropathic pain, spasticity, and cardiovascular autonomic dysfunction in individuals with SCI. We anticipate that the results of this original study will provide key information for a future clinical trial on the use of continuous positive airway pressure (CPAP) therapy for moderate-to-severe SRBDs, which may better control neuropathic pain, spasticity, and cardiovascular autonomic dysfunction among individuals with SCI. TRIAL REGISTRATION The research protocol for this study was registered in the ClinicalTrials.gov website (NCT05687097). https://clinicaltrials.gov/ct2/show/NCT05687097.
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Affiliation(s)
- Julio Cesar Furlan
- Toronto Rehabilitation Institute, Lyndhurst Centre, University Health Network, Toronto, Ontario, Canada
- KITE Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada
| | - Eldon Loh
- Department of Physical Medicine and Rehabilitation, University of Western Ontario, London, ON, Canada
- Parkwood Institute Research, Lawson Health Research Institute, London, ON, Canada
| | - Mark Iskander Boulos
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Sunnybrook Research Institute and Sunnybrook Health Sciences Centre, Hurvitz Brain Sciences Research Program, Toronto, ON, Canada
- Department of Medicine, Division of Neurology, University of Toronto, Toronto, ON, Canada
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The effects of lavandula aromatherapy on pain relief after coronary artery bypass graft surgery: A randomized clinical trial. Appl Nurs Res 2022; 68:151638. [PMID: 36473717 DOI: 10.1016/j.apnr.2022.151638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 08/17/2022] [Accepted: 10/25/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND AIMS Coronary artery bypass graft surgery (CABG) is a primary treatment in coronary artery disease (CAD). Patients experience pain after CABG. Pain may increase postoperative complications and decrease quality of life (QoL). This study aims to determine the lavandula aromatherapy effect on patients' pain after CABG. METHODS 98 patients undergoing CABG were randomly assigned to intervention and placebo groups. The intervention group inhaled 5-drops of 20 % lavandula essential oil (LEO) and the placebo group was exposed to 5-drop of distilled water. LEO or distilled water were dropped into a sterile gauze converted to the form of a necklace. The subjects wore necklace for three consecutive days and intervention was performed each 24 h. The pain intensity, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured before each intervention and 30 min after it. Also, the mean analgesic intake was recorded. SPSS version 16 was used to analyze the data. RESULTS The mean pain score measured in the intervention group showed a more decrease than that obtained in the placebo group after the first and second interventions. Additionally, the mean pain score in the intervention group demonstrated a significant decrease than the placebo group after the second intervention (P=0.008). Moreover, mean SBP after the second intervention (P=0.046) and mean DBP after the first intervention (P=0.029) revealed a significant difference between two groups. Moreover, the intervention group received less analgesic than the placebo group. CONCLUSIONS Lavandula aromatherapy can reduce pain and received analgesic dose after CABG.
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Zheng Q, Xie W, Lückemeyer DD, Lay M, Wang XW, Dong X, Limjunyawong N, Ye Y, Zhou FQ, Strong JA, Zhang JM, Dong X. Synchronized cluster firing, a distinct form of sensory neuron activation, drives spontaneous pain. Neuron 2022; 110:209-220.e6. [PMID: 34752775 PMCID: PMC8776619 DOI: 10.1016/j.neuron.2021.10.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 09/01/2021] [Accepted: 10/13/2021] [Indexed: 01/21/2023]
Abstract
Spontaneous pain refers to pain occurring without external stimuli. It is a primary complaint in chronic pain conditions and remains difficult to treat. Moreover, the mechanisms underlying spontaneous pain remain poorly understood. Here we employed in vivo imaging of dorsal root ganglion (DRG) neurons and discovered a distinct form of abnormal spontaneous activity following peripheral nerve injury: clusters of adjacent DRG neurons firing synchronously and sporadically. The level of cluster firing correlated directly with nerve injury-induced spontaneous pain behaviors. Furthermore, we demonstrated that cluster firing is triggered by activity of sympathetic nerves, which sprout into DRGs after injury, and identified norepinephrine as a key neurotransmitter mediating this unique firing. Chemogenetic and pharmacological manipulations of sympathetic activity and norepinephrine receptors suggest that they are necessary and sufficient for DRG cluster firing and spontaneous pain behavior. Therefore, blocking sympathetically mediated cluster firing may be a new paradigm for treating spontaneous pain.
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Affiliation(s)
- Qin Zheng
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA
| | - Wenrui Xie
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Debora D Lückemeyer
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Mark Lay
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA
| | - Xue-Wei Wang
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA
| | - Xintong Dong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA
| | - Nathachit Limjunyawong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA
| | - Yaqing Ye
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA
| | - Feng-Quan Zhou
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA
| | - Judith A Strong
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Jun-Ming Zhang
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21209, USA.
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Sherman K, Woyach V, Eisenach JC, Hopp FA, Cao F, Hogan QH, Dean C. Heterogeneity in patterns of pain development after nerve injury in rats and the influence of sex. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2021; 10:100069. [PMID: 34381929 PMCID: PMC8339380 DOI: 10.1016/j.ynpai.2021.100069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
The genesis of neuropathic pain is complex, as sensory abnormalities may differ between patients with different or similar etiologies, suggesting mechanistic heterogeneity, a concept that is largely unexplored. Yet, data are usually grouped for analysis based on the assumption that they share the same underlying pathogenesis. Sex is a factor that may contribute to differences in pain responses. Neuropathic pain is more prevalent in female patients, but pre-clinical studies that can examine pain development in a controlled environment have typically failed to include female subjects. This study explored patterns of development of hyperalgesia-like behavior (HLB) induced by noxious mechanical stimulation in a neuropathic pain model (spared nerve injury, SNI) in both male and female rats, and autonomic dysfunction that is associated with chronic pain. HLB was analyzed across time, using both discrete mixture modeling and rules-based longitudinal clustering. Both methods identified similar groupings of hyperalgesia trajectories after SNI that were not evident when data were combined into groups by sex only. Within the same hyperalgesia development group, mixed models showed that development of HLB in females was delayed relative to males and reached a magnitude similar to or higher than males. The data also indicate that sympathetic tone (as indicated by heart rate variability) drops below pre-SNI level before or at the onset of development of HLB. This study classifies heterogeneity in individual development of HLB and identifies sexual dimorphism in the time course of development of neuropathic pain after nerve injury. Future studies addressing mechanisms underlying these differences could facilitate appropriate pain treatments.
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Affiliation(s)
- Katherine Sherman
- Research Division, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, United States
| | - Victoria Woyach
- Research Division, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, United States
- Department of Anesthesiology, Medical College of Wisconsin and Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53226, United States
| | - James C. Eisenach
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Francis A. Hopp
- Research Division, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, United States
| | - Freddy Cao
- College of Nursing, University of Wisconsin – Milwaukee, Milwaukee, WI 53222, United States
| | - Quinn H. Hogan
- Research Division, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, United States
- Department of Anesthesiology, Medical College of Wisconsin and Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53226, United States
| | - Caron Dean
- Research Division, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, United States
- Department of Anesthesiology, Medical College of Wisconsin and Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53226, United States
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Santarcangelo EL, Carli G. Individual Traits and Pain Treatment: The Case of Hypnotizability. Front Neurosci 2021; 15:683045. [PMID: 34149351 PMCID: PMC8206467 DOI: 10.3389/fnins.2021.683045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/05/2021] [Indexed: 12/11/2022] Open
Affiliation(s)
- Enrica Laura Santarcangelo
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Giancarlo Carli
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
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Nie S, Lu J, Huang Y, Li QA. Zonisamide-loaded triblock copolymer nanomicelle as a controlled drug release platform for the treatment of oxidative stress -induced spinal cord neuronal damage. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.115233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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WeiWei Y, WenDi F, Mengru C, Tuo Y, Chen G. The cellular mechanism by which the rostral ventromedial medulla acts on the spinal cord during chronic pain. Rev Neurosci 2021; 32:545-558. [PMID: 33565739 DOI: 10.1515/revneuro-2020-0121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 12/18/2020] [Indexed: 11/15/2022]
Abstract
Clinical therapies for chronic pain are limited. While targeted drugs are promising therapies for chronic pain, they exhibit insufficient efficacy and poor targeting. The occurrence of chronic pain partly results from central changes caused by alterations in neurons in the rostral ventromedial medulla (RVM) in the brainstem regulatory pathway. The RVM, which plays a key role in the descending pain control pathway, greatly contributes to the development and maintenance of pain. However, the exact roles of the RVM in chronic pain remain unclear, making it difficult to develop new drugs targeting the RVM and related pathways. Here, we first discuss the roles of the RVM and related circuits in chronic pain. Then, we analyze synaptic transmission between RVM neurons and spinal cord neurons, specifically focusing on the release of neurotransmitters, to explore the cellular mechanisms by which the RVM regulates chronic pain. Finally, we propose some ideas for the development of drugs targeting the RVM.
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Affiliation(s)
- Yu WeiWei
- Key Laboratory of Neuroregeneration of Jiangsu and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong226001, China
| | - Fei WenDi
- Key Laboratory of Neuroregeneration of Jiangsu and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong226001, China
| | - Cui Mengru
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong226001, China
| | - Yang Tuo
- Department of Hand Surgery, China-Japan Union Hospital of Jilin University, Changchun130033, China
| | - Gang Chen
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong226001, China.,Department of Tissue and Embryology, Medical School of Nantong University, Co-innovation Center of Neuroregeneration, Nantong University, Nantong226001, China
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Alterations of Dopamine-Related Transcripts in A11 Diencephalospinal Pathways after Spinal Cord Injury. Neural Plast 2021; 2021:8838932. [PMID: 33510781 PMCID: PMC7822663 DOI: 10.1155/2021/8838932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/04/2020] [Accepted: 01/05/2021] [Indexed: 12/15/2022] Open
Abstract
The diencephalic A11 nuclei are the primary source of spinal dopamine (DA). Neurons in this region project to all levels of the spinal cord. Traumatic spinal cord injury (SCI) often interrupts descending and ascending neuronal pathways and further elicits injury-induced neuronal plasticity. However, it is unknown how A11 neurons and projections respond to SCI-induced axotomy. Based on preliminary observation, we hypothesized that A11 DA-ergic neurons rostral to the lesion site might change their capacity to synthesize DA after SCI. Adult rats received a complete spinal cord transection at the 10th thoracic (T10) level. After 3 or 8 weeks, rostral (T5) and caudal (L1) spinal cord tissue was collected to measure mRNA levels of DA-related genes. Meanwhile, A11 neurons in the brain were explicitly isolated by laser capture microdissection, and single-cell qPCR was employed to evaluate mRNA levels in the soma. Histological analysis was conducted to assess the number of A11 DA-ergic neurons. The results showed that, compared to naïve rats, mRNA levels of tyrosine hydroxylase (TH), dopamine decarboxylase (DDC), and D2 receptors in the T5 spinal segment had a transient decrease and subsequent recovery. However, dopamine-β-hydroxylase (DBH), D1 receptors, and DA-associated transcription factors did not change following SCI. Furthermore, axon degeneration below the lesion substantially reduced mRNA levels of TH and D2 in the L1 spinal segment. However, DDC transcript underwent only a temporary decrease. Similar mRNA levels of DA-related enzymes were detected in the A11 neuronal soma between naïve and SCI rats. In addition, immunostaining revealed that the number of A11 DA neurons did not change after SCI, indicating a sustention of capacity to synthesize DA in the neuroplasm. Thus, impaired A11 diencephalospinal pathways following SCI may transiently reduce DA production in the spinal cord rostral to the lesion but not in the brain.
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Gourlan M, Pellechia A, Robineau S, Foulon B, Gault D, Lefort M, Goossens D, Mathieu S, Laffont I, Dupeyron A, Ninot G, Gelis A. "What pressure ulcers mean to me?" Representations of pressure ulcer in persons with spinal cord injury: A qualitative study. J Tissue Viability 2020; 29:324-330. [PMID: 32830010 DOI: 10.1016/j.jtv.2020.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Explore the perceptions and beliefs related to pressure ulcers (PU), their prevention and treatment strategies, in order to discuss potential learning objectives for PU-related therapeutic education in persons with spinal cord injury (SCI). DESIGN Qualitative study, using grounded theory for the analysis of data collected via a questionnaire. SETTING Nine SCI referral centers, inpatient care. PARTICIPANTS 131 persons with SCI were included. 76% were male, and 65% presented with paraplegia. The median age was 48 years (33.5; 58) and median time since injury was 11 years (3; 24.5). 70% had experience with PU. INTERVENTIONS None. MAIN OUTCOME MEASURES Data collection via an open-ended questionnaire on the representation of PU, its prevention and life experience of having a PU. RESULTS Six categories were identified: (1) identifying what might become problematic, (2) daily preventive actions, (3) detecting the early signs, (4) managing the early signs, (5) need for care, (6) experience with PU and being bedridden. Pressure ulcers have dramatic consequences on psychosocial health. Prevention and treatment require self-management skills, such as self-risk assessment abilities, self-detection skills and problem-solving strategies, to optimise daily PU prevention in persons with SCI. CONCLUSION PU prevention tackled by persons with SCI bears some specificities that the physician must take into account in the construction of a self-management program in this high-risk population.
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Affiliation(s)
- Mathieu Gourlan
- Laboratoire Epsylon EA 4556, Université de Montpellier, University, Rue Henri Serre, Montpellier, France
| | - Alessandra Pellechia
- Unité Transversale D'éducation Du Patient (UTEP), CHU Montpellier, Hôpital La Colombière, 39 Avenue Charles Flahault, 34295, Montpellier, Cedex 5, France
| | - Sandrine Robineau
- Pôle de Médecine Physique et de Réadaptation Saint Helier, 54 Rue Saint Helier, Rennes, France
| | - Bernard Foulon
- Association des Paralysés de France, 1620 Rue de Saint Priest, 34090, Montpellier, France
| | - Dominique Gault
- Centre de Rééducation Clemenceau, 45 Boulevard Clemenceau, 67000, Strasbourg, France
| | - Marc Lefort
- Département de Médecine Physique et de Réadaptation, CHU Saint Jacques, 85 Rue Saint-Jacques, 44093, Nantes, France
| | - David Goossens
- Centre de Rééducation de La Tour de Gassies, 33520, Bruges, France
| | - Sarah Mathieu
- Centre de Rééducation Fonctionnelle de Kerpape, Ploemeur, 92 Rue de L'Anse Du Stole, 56270, France
| | - Isabelle Laffont
- Département de Médecine Physique et de Réadaptation, CHU Lapeyronie, 371 Avenue Du Doyen Gaston GIRAUD, Montpellier, France
| | - Arnaud Dupeyron
- Département de Médecine Physique et de Réadaptation, CHU Caremeau, 4 Rue Du Pr Debré, Nîmes, France
| | - Gregory Ninot
- Laboratoire Epsylon EA 4556, Université de Montpellier, University, Rue Henri Serre, Montpellier, France
| | - Anthony Gelis
- Laboratoire Epsylon EA 4556, Université de Montpellier, University, Rue Henri Serre, Montpellier, France; Département de Médecine Physique et de Réadaptation, CHU Lapeyronie, 371 Avenue Du Doyen Gaston GIRAUD, Montpellier, France; Centre Mutualiste Neurologique PROPARA, 263 Rue Du Caducée, Montpellier, France.
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O'Reilly ML, Tom VJ. Neuroimmune System as a Driving Force for Plasticity Following CNS Injury. Front Cell Neurosci 2020; 14:187. [PMID: 32792908 PMCID: PMC7390932 DOI: 10.3389/fncel.2020.00187] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/29/2020] [Indexed: 12/15/2022] Open
Abstract
Following an injury to the central nervous system (CNS), spontaneous plasticity is observed throughout the neuraxis and affects multiple key circuits. Much of this spontaneous plasticity can elicit beneficial and deleterious functional outcomes, depending on the context of plasticity and circuit affected. Injury-induced activation of the neuroimmune system has been proposed to be a major factor in driving this plasticity, as neuroimmune and inflammatory factors have been shown to influence cellular, synaptic, structural, and anatomical plasticity. Here, we will review the mechanisms through which the neuroimmune system mediates plasticity after CNS injury. Understanding the role of specific neuroimmune factors in driving adaptive and maladaptive plasticity may offer valuable therapeutic insight into how to promote adaptive plasticity and/or diminish maladaptive plasticity, respectively.
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Affiliation(s)
- Micaela L O'Reilly
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Veronica J Tom
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
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Yasko JR, Moss IL, Mains RE. Transcriptional Profiling of Non-injured Nociceptors After Spinal Cord Injury Reveals Diverse Molecular Changes. Front Mol Neurosci 2019; 12:284. [PMID: 32038157 PMCID: PMC6988781 DOI: 10.3389/fnmol.2019.00284] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/08/2019] [Indexed: 01/01/2023] Open
Abstract
Traumatic spinal cord injury (SCI) has devastating implications for patients, including a high predisposition for developing chronic pain distal to the site of injury. Chronic pain develops weeks to months after injury, consequently, patients are treated after irreparable changes have occurred. Nociceptors are central to chronic pain; however, the diversity of this cellular population presents challenges to understanding mechanisms and attributing pain modalities to specific cell types. To begin to address how peripheral sensory neurons below the injury level may contribute to the below-level pain reported by SCI patients, we examined SCI-induced changes in gene expression in lumbar dorsal root ganglia (DRG) below the site of injury. SCI was performed at the T10 vertebral level, with injury produced by a vessel clip with a closing pressure of 15 g for 1 min. Alterations in gene expression produce long-term sensory changes, therefore, we were interested in studying SCI-induced transcripts before the onset of chronic pain, which may trigger changes in downstream signaling pathways and ultimately facilitate the transmission of pain. To examine changes in the nociceptor subpopulation in DRG distal to the site of injury, we retrograde labeled sensory neurons projecting to the hairy hindpaw skin with fluorescent dye and collected the corresponding lumbar (L2–L6) DRG 4 days post-injury. Following dissociation, labeled neurons were purified by fluorescence-activated cell sorting (FACS). RNA was extracted from sorted sensory neurons of naïve, sham, or SCI mice and sequenced. Transcript abundances validated that the desired population of nociceptors were isolated. Cross-comparisons to data sets from similar studies confirmed, we were able to isolate our cells of interest and identify a unique pattern of gene expression within a subpopulation of neurons projecting to the hairy hindpaw skin. Differential gene expression analysis showed high expression levels and significant transcript changes 4 days post-injury in SCI cell populations relevant to the onset of chronic pain. Regulatory interrelationships predicted by pathway analysis implicated changes within the synaptogenesis signaling pathway as well as networks related to inflammatory signaling mechanisms, suggesting a role for synaptic plasticity and a correlation with pro-inflammatory signaling in the transition from acute to chronic pain.
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Affiliation(s)
- Jessica R Yasko
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Isaac L Moss
- Department of Orthopedic Surgery and the Comprehensive Spine Center, University of Connecticut Health Center, Farmington, CT, United States
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
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Feldman-Goriachnik R, Hanani M. The effects of sympathetic nerve damage on satellite glial cells in the mouse superior cervical ganglion. Auton Neurosci 2019; 221:102584. [PMID: 31494528 DOI: 10.1016/j.autneu.2019.102584] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 08/23/2019] [Accepted: 08/23/2019] [Indexed: 12/14/2022]
Abstract
Neurons in sensory, sympathetic, and parasympathetic ganglia are surrounded by satellite glial cell (SGCs). There is little information on the effects of nerve damage on SGCs in autonomic ganglia. We studied the consequences of damage to sympathetic nerve terminals by 6-hydroxydopamine (6-OHDA) on SGCs in the mouse superior cervical ganglia (Sup-CG). Immunostaining revealed that at 1-30 d post-6-OHDA injection, SGCs in Sup-CG were activated, as assayed by upregulation of glial fibrillary acidic protein. Intracellular labeling showed that dye coupling between SGCs around different neurons increased 4-6-fold 1-14 d after 6-OHDA injection. Behavioral testing 1-7 d post-6-OHDA showed that withdrawal threshold to tactile stimulation of the hind paws was reduced by 65-85%, consistent with hypersensitivity. A single intraperitoneal injection of the gap junction blocker carbenoxolone restored normal tactile thresholds in 6-OHDA-treated mice, suggesting a contribution of SGC gap junctions to pain. Using calcium imaging we found that after 6-OHDA treatment responses of SGCs to ATP were increased by about 30% compared with controls, but responses to ACh were reduced by 48%. The same experiments for SGCs in trigeminal ganglia from 6-OHDA injected mice showed no difference from controls, confirming that 6-OHDA acted selectively on sympathetic nerves. However, systemic inflammation induced by lipopolysaccharide did not affect SGCs of Sup-CG, but did influence SGCs in trigeminal ganglia in the same manner as 6-OHDA did on SGCs in Sup-CG. We conclude that even though SGCs in sympathetic and sensory ganglia are morphologically similar, they are quite different functionally, particularly after damage.
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Affiliation(s)
- Rachel Feldman-Goriachnik
- Laboratory of Experimental Surgery, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem 91240, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Menachem Hanani
- Laboratory of Experimental Surgery, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem 91240, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Israel.
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Karri J, Li S, Chen YT, Stampas A, Li S. Observations of Autonomic Variability Following Central Neuromodulation for Chronic Neuropathic Pain in Spinal Cord Injury. Neuromodulation 2019; 24:427-433. [PMID: 31199549 DOI: 10.1111/ner.12979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/31/2019] [Accepted: 05/08/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND Spinal cord injury (SCI) persons with chronic neuropathic pain (NP) demonstrate maladaptive autonomic profiles compared to SCI counterparts without NP (SCI - NP) or able-bodied (AB) controls. These aberrations may be secondary to maladaptive neuroplasticity in the shared circuitry of the pain neuromatrix-central autonomic network interface (PNM-CAN). In this study, we explored the proposed PNM-CAN mechanism in SCI + NP and AB cohorts following centrally-directed neuromodulation to assess if the PNM and CAN are capable of being differentially modulated. MATERIALS AND METHODS Central neuromodulation was administered via breathing-controlled electrical stimulation (BreEStim), previously evidenced to operate at the PNM. To quantify CAN activity, conventional heart rate variability (HRV) recordings were used to gather time and frequency domain parameters of autonomic modulation. SCI + NP (n = 10) and AB (n = 13) cohorts received null and active BreEStim randomly in crossover fashion. HRV data were gathered pretest and 30 minutes posttest. Pain modulation was quantified at both time-points by visual analog scale (VAS) for SCI + NP persons and electrical detection and pain threshold levels (EDT, EPT) for AB persons. RESULTS Following active BreEStim only, SCI + NP persons demonstrated increased parasympathetic tone (increased NN50, p = 0.03, and pNN50, p = 0.02, HRV parameters). This parasympathetic restoration was associated with analgesia (VAS reduction, p < 0.01). Similarly, AB persons demonstrated increased noxious tolerance (increased EPT, p = 0.03, with preserved EDL, p = 0.78) only following active BreEStim. However, this increased pain threshold was not associated with autonomic changes. CONCLUSIONS Central modulation targeting the PNM produced autonomic changes in SCI + NP persons but not AB persons. These findings suggest that AB persons exhibit intact CAN mechanisms capable of compensating for PNM aberrations or simply that SCI + NP persons exhibit altered PNM-CAN machinery altogether. Our collective findings confirm the interconnectedness and maladaptive plasticity of PNM-CAN machinery in SCI + NP persons and suggest that the PNM and CAN circuitry can be differentially modulated.
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Affiliation(s)
- Jay Karri
- Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX, USA.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA
| | - Shengai Li
- TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA.,Department of Physical Medicine and Rehabilitation, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yen-Ting Chen
- TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA.,Department of Physical Medicine and Rehabilitation, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Argyrios Stampas
- TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA.,Department of Physical Medicine and Rehabilitation, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Sheng Li
- TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA.,Department of Physical Medicine and Rehabilitation, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
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Chariker JH, Gomes C, Brabazon F, Harman KA, Ohri SS, Magnuson DSK, Whittemore SR, Petruska JC, Rouchka EC. Transcriptome of dorsal root ganglia caudal to a spinal cord injury with modulated behavioral activity. Sci Data 2019; 6:83. [PMID: 31175296 PMCID: PMC6555821 DOI: 10.1038/s41597-019-0088-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/29/2019] [Indexed: 12/30/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating clinical condition resulting in significant disabilities. Apart from local injury within the spinal cord, SCI patients develop a myriad of complications including multi-organ dysfunction. Some of the dysfunctions may be directly or indirectly related to the sensory neurons of the dorsal root ganglia (DRG), which signal to both the spinal cord and the peripheral organs. After SCI, some classes of DRG neurons exhibit sensitization and undergo axonal sprouting both peripherally and centrally. Such physiological and anatomical re-organization after SCI contributes to both adaptive and maladaptive plasticity processes, which may be modulated by activity and exercise. In this study, we collected comprehensive gene expression data in whole DRG below the levels of the injury to compare the effects of SCI with and without two different forms of exercise in rats.
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Affiliation(s)
- Julia H Chariker
- Department of Neuroscience Training, University of Louisville, 522 East Gray Street, Louisville, Kentucky, 40202, USA
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, 522 East Gray Street, Louisville, Kentucky, 40202, USA
| | - Cynthia Gomes
- Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
| | - Fiona Brabazon
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA
- Wiley Publishing, Hoboken, NJ, 07030, USA
| | - Kathryn A Harman
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Health & Sport Sciences, University of Louisville, 2100 South Floyd Street, Louisville, KY, 40208, USA
| | - Sujata Saraswat Ohri
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA
| | - David S K Magnuson
- Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA
| | - Scott R Whittemore
- Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA
| | - Jeffrey C Petruska
- Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA.
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA.
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA.
| | - Eric C Rouchka
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, 522 East Gray Street, Louisville, Kentucky, 40202, USA.
- Department of Computer Engineering and Computer Science, Speed School of Engineering, University of Louisville, Duthie Center for Engineering, 2301 South 3rd St., Louisville, Kentucky, 40292, USA.
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Odem MA, Bavencoffe AG, Cassidy RM, Lopez ER, Tian J, Dessauer CW, Walters ET. Isolated nociceptors reveal multiple specializations for generating irregular ongoing activity associated with ongoing pain. Pain 2018; 159:2347-2362. [PMID: 30015712 PMCID: PMC6193853 DOI: 10.1097/j.pain.0000000000001341] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ongoing pain has been linked to ongoing activity (OA) in human C-fiber nociceptors, but rodent models of pain-related OA have concentrated on allodynia rather than ongoing pain, and on OA generated in non-nociceptive Aβ fibers rather than C-fiber nociceptors. Little is known about how ongoing pain or nociceptor OA is generated. To define neurophysiological alterations underlying nociceptor OA, we have used isolated dorsal root ganglion neurons that continue to generate OA after removal from animals displaying ongoing pain. We subclassify OA as either spontaneous activity generated solely by alterations intrinsic to the active neuron or as extrinsically driven OA. Both types of OA were implicated previously in nociceptors in vivo and after isolation following spinal cord injury, which produces chronic ongoing pain. Using novel automated algorithms to analyze irregular changes in membrane potential, we have found, in a distinctive, nonaccommodating type of probable nociceptor, induction by spinal cord injury of 3 alterations that promote OA: (1) prolonged depolarization of resting membrane potential, (2) a hyperpolarizing shift in the voltage threshold for action potential generation, and (3) an increase in the incidence of large depolarizing spontaneous fluctuations (DSFs). Can DSFs also be enhanced acutely to promote OA in neurons from uninjured animals? A low dose of serotonin failed to change resting membrane potential but lowered action potential threshold. When combined with artificial depolarization to model inflammation, serotonin also strongly potentiated DSFs and OA. These findings reveal nociceptor specializations for generating OA that may promote ongoing pain in chronic and acute conditions.
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Affiliation(s)
- Max A. Odem
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Alexis G. Bavencoffe
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Ryan M. Cassidy
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Elia R. Lopez
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Jinbin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Carmen W. Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Edgar T. Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
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Shiao R, Lee-Kubli CA. Neuropathic Pain After Spinal Cord Injury: Challenges and Research Perspectives. Neurotherapeutics 2018; 15:635-653. [PMID: 29736857 PMCID: PMC6095789 DOI: 10.1007/s13311-018-0633-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that remains difficult to treat because underlying mechanisms are not yet fully understood. In part, this is due to limitations of evaluating neuropathic pain in animal models in general, and SCI rodents in particular. Though pain in patients is primarily spontaneous, with relatively few patients experiencing evoked pains, animal models of SCI pain have primarily relied upon evoked withdrawals. Greater use of operant tasks for evaluation of the affective dimension of pain in rodents is needed, but these tests have their own limitations such that additional studies of the relationship between evoked withdrawals and operant outcomes are recommended. In preclinical SCI models, enhanced reflex withdrawal or pain responses can arise from pathological changes that occur at any point along the sensory neuraxis. Use of quantitative sensory testing for identification of optimal treatment approach may yield improved identification of treatment options and clinical trial design. Additionally, a better understanding of the differences between mechanisms contributing to at- versus below-level neuropathic pain and neuropathic pain versus spasticity may shed insights into novel treatment options. Finally, the role of patient characteristics such as age and sex in pathogenesis of neuropathic SCI pain remains to be addressed.
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Affiliation(s)
- Rani Shiao
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines, La Jolla, California, 92073, USA
| | - Corinne A Lee-Kubli
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines, La Jolla, California, 92073, USA.
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Yasko JR, Mains RE. Chronic pain following spinal cord injury: Current approaches to cellular and molecular mechanisms. TRENDS IN CELL & MOLECULAR BIOLOGY 2018; 13:67-84. [PMID: 33564218 PMCID: PMC7869846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Traumatic spinal cord injury (SCI) has devastating implications for patients, including a high prevalence of chronic pain. Despite advancements in our understanding of the mechanisms involved post-SCI, there are no effective treatments for chronic pain following injury. The development of new treatment interventions for pain is needed, but this requires improved models to assess injury-related cellular, neurophysiological and molecular changes in the spinal cord. Here, we will discuss recent animal models for SCI, molecular screening for altered patterns of gene expression, and the importance of injury severity and timing after SCI.
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