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Cui X, Zhang Z, Xi H, Liu K, Zhu B, Gao X. Sympathetic-Sensory Coupling as a Potential Mechanism for Acupoints Sensitization. J Pain Res 2023; 16:2997-3004. [PMID: 37667684 PMCID: PMC10475306 DOI: 10.2147/jpr.s424841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/15/2023] [Indexed: 09/06/2023] Open
Abstract
A series of studies have demonstrated acupoint sensitization, in which acupoints can be activated in combination with sensory hypersensitivity and functional plasticity during visceral disorders. However, the mechanisms of acupoint sensitization remain unclear. Neuroanatomy evidence showed nociceptors innervated in acupoints contribute to the mechanism of acupoint sensitization. Increasing studies suggested sympathetic nerve plays a key role in modulating sensory transmission by sprouting or coupling with sensory neuron/nociceptor in the peripheral, forming the functional structure of the sympathetic-sensory coupling. Notably, the sensory inputs of the disease-induced sensitized acupoint contribute to the homeostatic regulation and also involve in delivering therapeutic information under acupuncture, hence, the role of sprouted sympathetic in acupoint function should be given attention. We herein reviewed the current knowledge of sympathetic and its sprouting in pain modulation, then discussed and highlighted the potential value of sympathetic-sensory coupling in acupoint functional plasticity.
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Affiliation(s)
- Xiang Cui
- Department of Physiology, Institute of Acupuncture and Moxibustion, Academy of Chinese Medical Sciences, Beijing, 100700, People’s Republic of China
| | - Ziyi Zhang
- Department of Physiology, Institute of Acupuncture and Moxibustion, Academy of Chinese Medical Sciences, Beijing, 100700, People’s Republic of China
- College of Acupuncture and Tuina, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi Province, 712046, People’s Republic of China
| | - Hanqing Xi
- Department of Physiology, Institute of Acupuncture and Moxibustion, Academy of Chinese Medical Sciences, Beijing, 100700, People’s Republic of China
| | - Kun Liu
- Department of Physiology, Institute of Acupuncture and Moxibustion, Academy of Chinese Medical Sciences, Beijing, 100700, People’s Republic of China
| | - Bing Zhu
- Department of Physiology, Institute of Acupuncture and Moxibustion, Academy of Chinese Medical Sciences, Beijing, 100700, People’s Republic of China
| | - Xinyan Gao
- Department of Physiology, Institute of Acupuncture and Moxibustion, Academy of Chinese Medical Sciences, Beijing, 100700, People’s Republic of China
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2
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Zheng Q, Dong X, Green DP, Dong X. Peripheral mechanisms of chronic pain. MEDICAL REVIEW 2022; 2:251-270. [PMID: 36067122 PMCID: PMC9381002 DOI: 10.1515/mr-2022-0013] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 06/13/2022] [Indexed: 11/15/2022]
Abstract
Abstract
Acutely, pain serves to protect us from potentially harmful stimuli, however damage to the somatosensory system can cause maladaptive changes in neurons leading to chronic pain. Although acute pain is fairly well controlled, chronic pain remains difficult to treat. Chronic pain is primarily a neuropathic condition, but studies examining the mechanisms underlying chronic pain are now looking beyond afferent nerve lesions and exploring new receptor targets, immune cells, and the role of the autonomic nervous system in contributing chronic pain conditions. The studies outlined in this review reveal how chronic pain is not only confined to alterations in the nervous system and presents findings on new treatment targets and for this debilitating disease.
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Affiliation(s)
- Qin Zheng
- Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Xintong Dong
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Dustin P. Green
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Howard Hughes Medical Institute, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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3
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Sahbaie P, Li WW, Guo TZ, Shi XY, Kingery WS, Clark JD. Autonomic Regulation of Nociceptive and Immunologic Changes in a Mouse Model of Complex Regional Pain Syndrome. THE JOURNAL OF PAIN 2022; 23:472-486. [PMID: 34699985 PMCID: PMC8920776 DOI: 10.1016/j.jpain.2021.09.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 09/27/2021] [Indexed: 01/16/2023]
Abstract
Chronic pain frequently develops after limb injuries, and its pathogenesis is poorly understood. We explored the hypothesis that the autonomic nervous system regulates adaptive immune system activation and nociceptive sensitization in a mouse model of chronic post-traumatic pain with features of complex regional pain syndrome (CRPS). In studies sympathetic signaling was reduced using 6-hydroxydopamine (6-OHDA) or lofexidine, while parasympathetic signaling was augmented by nicotine administration. Hindpaw allodynia, unweighting, skin temperature, and edema were measured at 3 and 7 weeks after fracture. Hypertrophy of regional lymph nodes and IgM deposition in the skin of injured limbs were followed as indices of adaptive immune system activation. Passive transfer of serum from fracture mice to recipient B cell deficient (muMT) mice was used to assess the formation of pain-related autoantibodies. We observed that 6-OHDA or lofexidine reduced fracture-induced hindpaw nociceptive sensitization and unweighting. Nicotine had similar effects. These treatments also prevented IgM deposition, hypertrophy of popliteal lymph nodes, and the development of pronociceptive serum transfer effects. We conclude that inhibiting sympathetic or augmenting parasympathetic signaling inhibits pro-nociceptive immunological changes accompanying limb fracture. These translational results support the use of similar approaches in trials potentially alleviating persistent post-traumatic pain and, possibly, CRPS. PERSPECTIVE: Selective treatments aimed at autonomic nervous system modulation reduce fracture-related nociceptive and functional sequelae. The same treatment strategies limit pain-supporting immune system activation and the production of pro-nociceptive antibodies. Thus, the therapeutic regulation of autonomic activity after limb injury may reduce the incidence of chronic pain.
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Affiliation(s)
- Peyman Sahbaie
- Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California; Department of Anesthesia, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California.
| | - Wen-Wu Li
- Anesthesiology Service; Veterans Affairs Palo Alto Health Care System; 3801 Miranda Ave, Palo Alto, CA 94304, U.S.A,Department of Anesthesia, Perioperative and Pain Medicine; Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tian-Zhi Guo
- Anesthesiology Service; Veterans Affairs Palo Alto Health Care System; 3801 Miranda Ave, Palo Alto, CA 94304, U.S.A,Palo Alto Veterans Institute for Research, 3801 Miranda Ave, Palo Alto, CA 94304, USA
| | - Xiao-you Shi
- Anesthesiology Service; Veterans Affairs Palo Alto Health Care System; 3801 Miranda Ave, Palo Alto, CA 94304, U.S.A,Department of Anesthesia, Perioperative and Pain Medicine; Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wade S. Kingery
- Palo Alto Veterans Institute for Research, 3801 Miranda Ave, Palo Alto, CA 94304, USA
| | - J David Clark
- Anesthesiology Service; Veterans Affairs Palo Alto Health Care System; 3801 Miranda Ave, Palo Alto, CA 94304, U.S.A,Department of Anesthesia, Perioperative and Pain Medicine; Stanford University School of Medicine, Stanford, CA 94305, USA
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4
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Ji Y, Shi W, Yang J, Ma B, Jin T, Cao B, Liu X, Ma K. Effect of sympathetic sprouting on the excitability of dorsal root ganglion neurons and afferents in a rat model of neuropathic pain. Biochem Biophys Res Commun 2022; 587:49-57. [PMID: 34864395 DOI: 10.1016/j.bbrc.2021.11.096] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 11/06/2021] [Accepted: 11/27/2021] [Indexed: 01/06/2023]
Abstract
Increased sympathetic nerve excitability has been reported to aggravate a variety of chronic pain conditions, and an increase in the number of sympathetic nerve fibers in the dorsal root ganglion (DRG) has been found in neuropathic pain (NP) models. However, the mechanism of the neurotransmitter norepinephrine (NE) released by sympathetic nerve fiber endings on the excitability of DRG neurons is still controversial, and the adrenergic receptor subtypes involved in this biological process are also controversial. In our study, we have two objectives: (1) To determine the effect of the neurotransmitter NE on the excitability of different neurons in DRG; (2) To determine which adrenergic receptors are involved in the excitability of DRG neurons by NE released by sprouting sympathetic fibers. In this experiment, a unique field potential recording method of spinal cord dorsal horn was innovatively adopted, which can be used for electrophysiological study in vivo. The results showed that: Forty days after SNI, patch clamp and field potential recording methods confirmed that NE enhanced the excitability of ipsilateral DRG large neurons, and then our in vivo electrophysiological results showed that the α2 receptor blocker Yohimbine could block the excitatory effect of NE on A-fiber and the inhibitory effect on C-fiber, while the α2A-adrenergic receptor agonist guanfacine (100 μM) had the same biological effect as NE. Finally, we concluded that NE from sympathetic fiber endings is involved in the regulation of pain signaling by acting on α2A-adrenergic receptors in DRG.
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Affiliation(s)
- Yun Ji
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wenjiao Shi
- Department of Anesthesiology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jie Yang
- Department of Physiology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Bingjie Ma
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Tian Jin
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Bingbing Cao
- Department of Anesthesiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, China
| | - Xianguo Liu
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.
| | - Ke Ma
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
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Wistrom E, Chase R, Smith PR, Campbell ZT. A compendium of validated pain genes. WIREs Mech Dis 2022; 14:e1570. [PMID: 35760453 PMCID: PMC9787016 DOI: 10.1002/wsbm.1570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/28/2022] [Accepted: 06/06/2022] [Indexed: 12/30/2022]
Abstract
The development of novel pain therapeutics hinges on the identification and rigorous validation of potential targets. Model organisms provide a means to test the involvement of specific genes and regulatory elements in pain. Here we provide a list of genes linked to pain-associated behaviors. We capitalize on results spanning over three decades to identify a set of 242 genes. They support a remarkable diversity of functions spanning action potential propagation, immune response, GPCR signaling, enzymatic catalysis, nucleic acid regulation, and intercellular signaling. Making use of existing tissue and single-cell high-throughput RNA sequencing datasets, we examine their patterns of expression. For each gene class, we discuss archetypal members, with an emphasis on opportunities for additional experimentation. Finally, we discuss how powerful and increasingly ubiquitous forward genetic screening approaches could be used to improve our ability to identify pain genes. This article is categorized under: Neurological Diseases > Genetics/Genomics/Epigenetics Neurological Diseases > Molecular and Cellular Physiology.
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Affiliation(s)
- Eric Wistrom
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Rebecca Chase
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Patrick R. Smith
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Zachary T. Campbell
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA,Center for Advanced Pain StudiesUniversity of Texas at DallasRichardsonTexasUSA
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Sillevis R, Trincado G, Shamus E. The immediate effect of a single session of pain neuroscience education on pain and the autonomic nervous system in subjects with persistent pain, a pilot study. PeerJ 2021; 9:e11543. [PMID: 34131526 PMCID: PMC8174152 DOI: 10.7717/peerj.11543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 05/10/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND The autonomic nervous system is a system that operates at the subconscious level and has been associated with neurobehavioral aspects of pain. Overall, persistent pain has a stimulating effect on the sympathetic nervous system. A promising emerging nonpharmacological treatment to manage persistent pain is neuroscience-based pain education. The overarching goal of neuroscience-based pain education is to change cognitions about pain and the pain experience through education. The aim was to determine the immediate and short-term impact of a neuroscience-based pain education video on the autonomic nervous system and pain in a subgroup of individuals with persistent pain. METHODS A convenience sample of 26 subjects were recruited for this study. Each subject indicated their pain level at the time of testing using a Visual Analogue Scale. Automated pupillometry was utilized to measure pupil diameter. After two minutes of accommodation to the goggles, the pupil was measured continuously for 60 s. Following this a 5-minute video presentation "Understanding Pain" was watched, followed by a continuous pupil measurement for 60 s. Three minutes after this measure, the final pupil diameter measurement was taken for 60 s. After completing the final pupil measure, the subject was asked to fill out a second Visual Analogue Scale and a Global Rate of Change. OUTCOMES Each subject completed a Global Rating of Change Scale and the mean score was 1.14 (SD = 1.61 and a SEM = 0.), supporting the hypothesis of an overall self-perceived benefit from the intervention. There was a statistically significant difference in pain following the video, P < 0.01. A significant correlation was observed between the self-perceived decrease in pain level and the Global Rating of Change score, p = 0.02. There was no statistically significant difference in the mean pupil diameter following the video with p = 0.76 for the right eye and p = 0.250 for the left eye. DISCUSSION This pilot study demonstrated that a 5-minute neuroscience-based pain education video reduced perceived pain in a small sample of subjects with persistent pain. Watching the neuroscience-based pain education video did not seem to result in an immediate generalized autonomic nervous system response. However, it resulted in a different reaction on each eye. This unequal response might be the result of the hemispheric lateralization of the ANS. This study supports the fact that the pain experience is determined by the balance between conscious cognitive processes and subconscious processes based on previous psychological experiences.
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Affiliation(s)
- Rob Sillevis
- Rehabilitations Sciences, Florida Gulf Coast University, Ft. Myers, FL, United States of America
| | - Gabriel Trincado
- Rehabilitations Sciences, Florida Gulf Coast University, Ft. Myers, FL, United States of America
| | - Eric Shamus
- Rehabilitations Sciences, Florida Gulf Coast University, Ft. Myers, FL, United States of America
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7
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Wei S, Qiu CY, Jin Y, Liu TT, Hu WP. Dexmedetomidine Inhibits ASIC Activity via Activation of α 2A Adrenergic Receptors in Rat Dorsal Root Ganglion Neurons. Front Pharmacol 2021; 12:685460. [PMID: 34108881 PMCID: PMC8181722 DOI: 10.3389/fphar.2021.685460] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/11/2021] [Indexed: 01/13/2023] Open
Abstract
Dexmedetomidine (DEX), a selective α2 adrenergic receptor (α2-AR) agonist, has been shown to have peripheral analgesic effects in a variety of pain conditions. However, the precise molecular mechanisms have not yet been fully elucidated. Acid sensing ion channels (ASICs) are the major player in pain associated with tissue acidosis. Given that both α2-ARs and ASICs exist in dorsal root ganglia (DRG) neurons, we therefore investigated the effects of DEX on the functional activity of ASICs. Herein, whole-cell patch-clamp recordings demonstrated that DEX suppressed ASIC-mediated and acid-evoked currents and action potentials in dissociated rat DRG neurons. DEX shifted downwards concentration-response curve to protons, with a decrease of 35.83 ± 3.91% in the maximal current response to pH 4.5. DEX-induced inhibition of ASIC currents was blocked by the α2A-AR antagonist BRL44408 in DRG neurons. DEX also inhibited ASIC3 currents in CHO cells co-expressing ASIC3 and α2A-ARs, but not in ASIC3 transfected CHO cells without α2A-ARs expression. DEX-induced inhibition of ASIC currents was mimicked by the protein kinase A inhibitor H-89, and blocked by intracellular application of the Gi/o protein inhibitor pertussis toxin and the cAMP analog 8-Br-cAMP. In addition, peripherally administration of DEX dose-dependently relieved nociceptive responses to intraplantar injection of acetic acid in rats through local α2A-ARs. Our results indicated that DEX inhibited the functional activity of ASICs via α2A-ARs and intracellular Gi/o proteins and cAMP/protein kinase A signaling pathway in rat DRG neurons, which was a novel potential mechanism that probably mediated peripheral analgesia of DEX.
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Affiliation(s)
- Shuang Wei
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China.,Department of Pharmacology, Hubei University of Science and Technology, Xianning, China
| | - Chun-Yu Qiu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Ying Jin
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Ting-Ting Liu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Wang-Ping Hu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
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8
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Chen W, McRoberts JA, Ennes HS, Marvizon JC. cAMP signaling through protein kinase A and Epac2 induces substance P release in the rat spinal cord. Neuropharmacology 2021; 189:108533. [PMID: 33744339 DOI: 10.1016/j.neuropharm.2021.108533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 03/01/2021] [Accepted: 03/11/2021] [Indexed: 11/18/2022]
Abstract
Using neurokinin 1 receptor (NK1R) internalization to measure of substance P release in rat spinal cord slices, we found that it was induced by the adenylyl cyclase (AC) activator forskolin, by the protein kinase A (PKA) activators 6-Bnz-cAMP and 8-Br-cAMP, and by the activator of exchange protein activated by cAMP (Epac) 8-pCPT-2-O-Me-cAMP (CPTOMe-cAMP). Conversely, AC and PKA inhibitors decreased substance P release induced by electrical stimulation of the dorsal root. Therefore, the cAMP signaling pathway mediates substance P release in the dorsal horn. The effects of forskolin and 6-Bnz-cAMP were not additive with NMDA-induced substance P release and were decreased by the NMDA receptor blocker MK-801. In cultured dorsal horn neurons, forskolin increased NMDA-induced Ca2+ entry and the phosphorylation of the NR1 and NR2B subunits of the NMDA receptor. Therefore, cAMP-induced substance P release is mediated by the activating phosphorylation by PKA of NMDA receptors. Voltage-gated Ca2+ channels, but not by TRPV1 or TRPA1, also contributed to cAMP-induced substance P release. Activation of PKA was required for the effects of forskolin and the three cAMP analogs. Epac2 contributed to the effects of forskolin and CPTOMe-cAMP, signaling through a Raf - mitogen-activated protein kinase pathway to activate Ca2+ channels. Epac1 inhibitors induced NK1R internalization independently of substance P release. In rats with latent sensitization to pain, the effect of 6-Bnz-cAMP was unchanged, whereas the effect of forskolin was decreased due to the loss of the stimulatory effect of Epac2. Hence, substance P release induced by cAMP decreases during pain hypersensitivity.
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Affiliation(s)
- Wenling Chen
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA; Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, 90073, USA
| | - James A McRoberts
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Helena S Ennes
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Juan Carlos Marvizon
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA; Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, 90073, USA.
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Chen W, Marvizón JC. A Src family kinase maintains latent sensitization in rats, a model of inflammatory and neuropathic pain. Brain Res 2020; 1746:146999. [PMID: 32579948 PMCID: PMC10866137 DOI: 10.1016/j.brainres.2020.146999] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/29/2020] [Accepted: 06/17/2020] [Indexed: 02/06/2023]
Abstract
Latent sensitization is a long-term model of chronic pain in which hyperalgesia is continuously suppressed by opioid receptors, as demonstrated by the induction of mechanical allodynia by opioid antagonists. Different intracellular signals may mediate the initiation, maintenance and expression of latent sensitization. Our criterion for the involvement of a signal in the maintenance of latent sensitization is that inhibitors should permanently eliminate the allodynia produced by an opioid antagonist. We hypothesized that Src family kinases (SFKs) maintain latent sensitization and tested this hypothesis by inducing latent sensitization in rats with complete Freund's adjuvant (CFA) or spared nerve injury. After measures of mechanical allodynia returned to baseline, vehicle or the SFK inhibitor PP2 were injected intrathecally. The opioid antagonist naltrexone injected intrathecally 15 min later produced allodynia in control rats but not in rats injected with PP2. Vehicle or PP2 were injected daily for two more days and naltrexone was injected five days later. Again, naltrexone induced allodynia in the control rats but not in the rats injected with PP2. Results were similar when latent sensitization was induced with CFA or spared nerve injury. We concluded that an SFK, likely Fyn, maintains latent sensitization induced by inflammation or nerve injury.
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Affiliation(s)
- Wenling Chen
- Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States; Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, United States
| | - Juan Carlos Marvizón
- Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States; Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, United States.
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10
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Chen W, Marvizon JC. Neurokinin 1 receptor activation in the rat spinal cord maintains latent sensitization, a model of inflammatory and neuropathic chronic pain. Neuropharmacology 2020; 177:108253. [PMID: 32736088 PMCID: PMC10863619 DOI: 10.1016/j.neuropharm.2020.108253] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/16/2020] [Accepted: 07/23/2020] [Indexed: 12/21/2022]
Abstract
Latent sensitization is a model of chronic pain in which a persistent state of pain hypersensitivity is suppressed by opioid receptors, as evidenced by the ability of opioid antagonists to induce a period of mechanical allodynia. Our objective was to determine if substance P and its neurokinin 1 receptor (NK1R) mediate the maintenance of latent sensitization. Latent sensitization was induced by injecting rats in the hindpaw with complete Freund's adjuvant (CFA), or by tibial spared nerve injury (SNI). When responses to von Frey filaments returned to baseline (day 28), the rats were injected intrathecally with saline or the NK1R antagonist RP67580, followed 15 min later by intrathecal naltrexone. In both pain models, the saline-injected rats developed allodynia for 2 h after naltrexone, but not the RP67580-injected rats. Saline or RP67580 were injected daily for two more days. Five days later (day 35), naltrexone was injected intrathecally. Again, the saline-injected rats, but not the RP67580-injected rats, developed allodynia in response to naltrexone. To determine if there is sustained activation of NK1Rs during latent sensitization, NK1R internalization was measured in lamina I neurons in rats injected in the paw with saline or CFA, and then injected intrathecally with saline or naltrexone on day 28. The rats injected with CFA had a small amount of NK1R internalization that was significantly higher than in the saline-injected rats. Naltrexone increased NK1R internalization in the CFA-injected rats but nor in the saline-injected rats. Therefore, sustained activation of NK1Rs maintains pain hypersensitivity during latent sensitization.
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Affiliation(s)
- Wenling Chen
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA; Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, 90073, USA
| | - Juan Carlos Marvizon
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA; Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, 90073, USA.
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11
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Mazy A, Ghanem MA, Abd Elatif MSE, Basyoni YE. Spinal anesthesia for lengthy lower limb orthopedic surgeries: dexmedetomidine plus fentanyl versus dexmedetomidine. AIN-SHAMS JOURNAL OF ANESTHESIOLOGY 2019; 11:10. [DOI: 10.1186/s42077-019-0024-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 03/12/2019] [Indexed: 09/02/2023]
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12
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Evaluation of protective effects of non-selective cannabinoid receptor agonist WIN 55,212-2 against the nitroglycerine-induced acute and chronic animal models of migraine: A mechanistic study. Life Sci 2019; 232:116670. [DOI: 10.1016/j.lfs.2019.116670] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 02/08/2023]
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13
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Marvizon JC, Chen W, Fu W, Taylor BK. Neuropeptide Y release in the rat spinal cord measured with Y1 receptor internalization is increased after nerve injury. Neuropharmacology 2019; 158:107732. [PMID: 31377198 DOI: 10.1016/j.neuropharm.2019.107732] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 07/31/2019] [Indexed: 12/18/2022]
Abstract
Neuropeptide Y (NPY) modulates nociception in the spinal cord, but little is known about its mechanisms of release. We measured NPY release in situ using the internalization of its Y1 receptor in dorsal horn neurons. Y1 receptor immunoreactivity was normally localized to the cell surface, but addition of NPY to spinal cord slices increased the number of neurons with Y1 internalization in a biphasic fashion (EC50s of 1 nM and 1 μM). Depolarization with KCl, capsaicin, or the protein kinase A activator 6-benzoyl-cAMP also induced Y1 receptor internalization, presumably by releasing NPY. NMDA receptor activation in the presence of BVT948, an inhibitor of protein tyrosine phosphatases, also released NPY. Electrical stimulation of the dorsal horn frequency-dependently induced NPY release; and this was decreased by the Y1 antagonist BIBO3304, the Nav channel blocker lidocaine, or the Cav2 channel blocker ω-conotoxin MVIIC. Dorsal root immersion in capsaicin, but not its electrical stimulation, also induced NPY release. This was blocked by CNQX, suggesting that part of the NPY released by capsaicin was from dorsal horn neurons receiving synapses from primary afferents and not from the afferent themselves. Mechanical stimulation in vivo, with rub or clamp of the hindpaw, elicited robust Y1 receptor internalization in rats with spared nerve injury but not sham surgery. In summary, NPY is released from dorsal horn interneurons or primary afferent terminals by electrical stimulation and by activation of TRPV1, PKA or NMDA receptors in. Furthermore, NPY release evoked by noxious and tactile stimuli increases after peripheral nerve injury.
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Affiliation(s)
- Juan Carlos Marvizon
- Vatche and Tamar Manoukian Division of Digestive Diseases, 900 Veterans Ave., Warren Hall Building, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA; Veteran Affairs Greater Los Angeles Healthcare System, 11310 Wilshire Blvd., Building 115, Los Angeles, CA, 90073, USA.
| | - Wenling Chen
- Vatche and Tamar Manoukian Division of Digestive Diseases, 900 Veterans Ave., Warren Hall Building, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA; Veteran Affairs Greater Los Angeles Healthcare System, 11310 Wilshire Blvd., Building 115, Los Angeles, CA, 90073, USA.
| | - Weisi Fu
- Department of Physiology, University of Kentucky Medical Center, Lexington, KY, USA.
| | - Bradley K Taylor
- Department of Physiology, University of Kentucky Medical Center, Lexington, KY, USA; Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA.
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Chen W, Taché Y, Marvizón JC. Corticotropin-Releasing Factor in the Brain and Blocking Spinal Descending Signals Induce Hyperalgesia in the Latent Sensitization Model of Chronic Pain. Neuroscience 2019; 381:149-158. [PMID: 29776484 DOI: 10.1016/j.neuroscience.2018.03.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 02/21/2018] [Accepted: 03/16/2018] [Indexed: 12/25/2022]
Abstract
Latent sensitization is a model of chronic pain in which an injury triggers a period of hyperalgesia followed by an apparent recovery, but in which pain sensitization persists but is suppressed by opioid and adrenergic receptors. One important characteristic of latent sensitization is that hyperalgesia can be triggered by acute stress. To determine whether the effect of stress is mimicked by the activation of corticotropin-releasing factor (CRF) signaling in the brain, rats with latent sensitization induced by injecting complete Freund's adjuvant (CFA, 50 μl) in one hind paw were given an intracerebroventricular (i.c.v.) injection of CRF. The i.c.v. injection of CRF (0.6 μg, 10 μl), but not saline, induced bilateral mechanical hyperalgesia in rats with latent sensitization. In contrast, CRF i.c.v. did not induce hyperalgesia in rats without latent sensitization (injected with saline in the hind paw). To determine whether descending pain inhibition mediates the suppression of hyperalgesia in latent sensitization, rats with CFA-induced latent sensitization received an intrathecal injection of lidocaine (10%, 1 μl) at the cervical-thoracic spinal cord to produce a spinal block. Lidocaine-injected rats, but not rats injected intrathecally with saline, developed bilateral mechanical hyperalgesia. Intrathecal lidocaine did not induce hyperalgesia in rats without latent sensitization (injected with saline in the hind paw). These results show that i.c.v. CRF mimicked the hyperalgesic response triggered by stress during latent sensitization, possibly by blocking inhibitory spinal descending signals that suppress hyperalgesia.
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Affiliation(s)
- Wenling Chen
- Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States; Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, United States.
| | - Yvette Taché
- Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States; Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, United States.
| | - Juan Carlos Marvizón
- Veteran Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States; Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, United States.
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15
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Gainfully employing descending controls in acute and chronic pain management. Vet J 2018; 237:16-25. [DOI: 10.1016/j.tvjl.2018.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 12/30/2022]
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Sustained Suppression of Hyperalgesia during Latent Sensitization by μ-, δ-, and κ-opioid receptors and α2A Adrenergic Receptors: Role of Constitutive Activity. J Neurosci 2016; 36:204-21. [PMID: 26740662 DOI: 10.1523/jneurosci.1751-15.2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Many chronic pain disorders alternate between bouts of pain and periods of remission. The latent sensitization model reproduces this in rodents by showing that the apparent recovery ("remission") from inflammatory or neuropathic pain can be reversed by opioid antagonists. Therefore, this remission represents an opioid receptor-mediated suppression of a sustained hyperalgesic state. To identify the receptors involved, we induced latent sensitization in mice and rats by injecting complete Freund's adjuvant (CFA) in the hindpaw. In WT mice, responses to mechanical stimulation returned to baseline 3 weeks after CFA. In μ-opioid receptor (MOR) knock-out (KO) mice, responses did not return to baseline but partially recovered from peak hyperalgesia. Antagonists of α2A-adrenergic and δ-opioid receptors reinstated hyperalgesia in WT mice and abolished the partial recovery from hyperalgesia in MOR KO mice. In rats, antagonists of α2A adrenergic and μ-, δ-, and κ-opioid receptors reinstated hyperalgesia during remission from CFA-induced hyperalgesia. Therefore, these four receptors suppress hyperalgesia in latent sensitization. We further demonstrated that suppression of hyperalgesia by MORs was due to their constitutive activity because of the following: (1) CFA-induced hyperalgesia was reinstated by the MOR inverse agonist naltrexone (NTX), but not by its neutral antagonist 6β-naltrexol; (2) pro-enkephalin, pro-opiomelanocortin, and pro-dynorphin KO mice showed recovery from hyperalgesia and reinstatement by NTX; (3) there was no MOR internalization during remission; (4) MORs immunoprecipitated from the spinal cord during remission had increased Ser(375) phosphorylation; and (5) electrophysiology recordings from dorsal root ganglion neurons collected during remission showed constitutive MOR inhibition of calcium channels. SIGNIFICANCE STATEMENT Chronic pain causes extreme suffering to millions of people, but its mechanisms remain to be unraveled. Latent sensitization is a phenomenon studied in rodents that has many key features of chronic pain: it is initiated by a variety of noxious stimuli, has indefinite duration, and pain appears in episodes that can be triggered by stress. Here, we show that, during latent sensitization, there is a sustained state of pain hypersensitivity that is continuously suppressed by the activation of μ-, δ-, and κ-opioid receptors and by adrenergic α2A receptors in the spinal cord. Furthermore, we show that the activation of μ-opioid receptors is not due to the release of endogenous opioids, but rather to its ligand-independent constitutive activity.
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Responses of Heart Rate Variability to Acute Pain After Minor Spinal Surgery. J Neurosurg Anesthesiol 2015; 27:148-54. [DOI: 10.1097/ana.0000000000000102] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Gu XY, Liu BL, Zang KK, Yang L, Xu H, Pan HL, Zhao ZQ, Zhang YQ. Dexmedetomidine inhibits Tetrodotoxin-resistant Nav1.8 sodium channel activity through Gi/o-dependent pathway in rat dorsal root ganglion neurons. Mol Brain 2015; 8:15. [PMID: 25761941 PMCID: PMC4350947 DOI: 10.1186/s13041-015-0105-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 02/18/2015] [Indexed: 11/12/2022] Open
Abstract
Background Systemically administered dexmedetomidine (DEX), a selective α2 adrenergic receptor (α2-AR) agonists, produces analgesia and sedation. Peripherally restricted α2-AR antagonist could block the analgesic effect of systemic DEX on neuropathic pain, with no effect on sedation, indicating peripheral analgesic effect of DEX. Tetrodotoxin-resistant (TTX-R) sodium channel Nav1.8 play important roles in the conduction of nociceptive sensation. Both α2-AR and Nav1.8 are found in small nociceptive DRG neurons. We, therefore, investigated the effects of DEX on the Nav1.8 currents in acutely dissociated small-diameter DRG neurons. Results Whole-cell patch-clamp recordings demonstrated that DEX concentration-dependently suppressed TTX-R Nav1.8 currents in small-diameter lumbar DRG neurons. DEX also shifted the steady-state inactivation curves of Nav1.8 in a hyperpolarizing direction and increased the threshold of action potential and decrease electrical and chemical stimuli-evoked firings in small-diameter DRG neurons. The α2-AR antagonist yohimbine or α2A-AR antagonist BRL44408 but not α2B-AR antagonist imiloxan blocked the inhibition of Nav1.8 currents by DEX. Immunohistochemistry results showed that Nav1.8 was predominantly expressed in peripherin-positive small-diameter DRG neurons, and some of them were α2A-AR-positive ones. Our electrophysiological recordings also demonstrated that DEX-induced inhibition of Nav1.8 currents was prevented by intracellular application of G-protein inhibitor GDPβ-s or Gi/o proteins inhibitor pertussis toxin (PTX), and bath application of adenylate cyclase (AC) activator forskolin or membrane-permeable cAMP analogue 8-Bromo-cAMP (8-Br-cAMP). PKA inhibitor Rp-cAMP could mimic DEX-induced inhibition of Nav1.8 currents. Conclusions We established a functional link between α2-AR and Nav1.8 in primary sensory neurons utilizing the Gi/o/AC/cAMP/PKA pathway, which probably mediating peripheral analgesia of DEX.
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Affiliation(s)
- Xi-Yao Gu
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Ben-Long Liu
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Kai-Kai Zang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Liu Yang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Hua Xu
- Department of Anesthesiology, Changhai Hospital, The Second Military Medical University, Shanghai, 200433, China.
| | - Hai-Li Pan
- Center for Neuropsychiatric Diseases, Institute of Life Science, Nanchang University, Nanchang, 330031, China.
| | - Zhi-Qi Zhao
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
| | - Yu-Qiu Zhang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
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Wei X, Yan J, Tillu D, Asiedu M, Weinstein N, Melemedjian O, Price T, Dussor G. Meningeal norepinephrine produces headache behaviors in rats via actions both on dural afferents and fibroblasts. Cephalalgia 2015; 35:1054-64. [PMID: 25601915 DOI: 10.1177/0333102414566861] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/06/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Stress is commonly reported to contribute to migraine although mechanisms by which this may occur are not fully known. The purpose of these studies was to examine whether norepinephrine (NE), the primary sympathetic efferent transmitter, acts on processes in the meninges that may contribute to the pain of migraine. METHODS NE was applied to rat dura using a behavioral model of headache. Primary cultures of rat trigeminal ganglia retrogradely labeled from the dura mater and of rat dural fibroblasts were prepared. Patch-clamp electrophysiology, Western blot, and ELISA were performed to examine the effects of NE. Conditioned media from NE-treated fibroblast cultures was applied to the dura using the behavioral headache model. RESULTS Dural injection both of NE and media from NE-stimulated fibroblasts caused cutaneous facial and hindpaw allodynia in awake rats. NE application to cultured dural afferents increased action potential firing in response to current injections. Application of NE to dural fibroblasts increased phosphorylation of ERK and caused the release of interleukin-6 (IL-6). CONCLUSIONS These data demonstrate that NE can contribute to pro-nociceptive signaling from the meninges via actions on dural afferents and dural fibroblasts. Together, these actions of NE may contribute to the headache phase of migraine.
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Affiliation(s)
- Xiaomei Wei
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Jin Yan
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Dipti Tillu
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Marina Asiedu
- Department of Pharmacology, The University of Arizona College of Medicine, USA School of Behavioral and Brain Sciences, The University of Texas at Dallas, USA
| | - Nicole Weinstein
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Ohannes Melemedjian
- Department of Pharmacology, The University of Arizona College of Medicine, USA
| | - Theodore Price
- Department of Pharmacology, The University of Arizona College of Medicine, USA School of Behavioral and Brain Sciences, The University of Texas at Dallas, USA
| | - Gregory Dussor
- Department of Pharmacology, The University of Arizona College of Medicine, USA School of Behavioral and Brain Sciences, The University of Texas at Dallas, USA
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Dong J, Yang L, Tang J, Zheng J. Dexmedetomidine alleviates rat post-ischemia induced allodynia through GRK2 upregulation in superior cervical ganglia. Auton Neurosci 2014; 187:76-83. [PMID: 25466829 DOI: 10.1016/j.autneu.2014.10.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 10/14/2014] [Accepted: 10/25/2014] [Indexed: 10/24/2022]
Abstract
A transient decrease in G protein-coupled receptor kinase 2 (GRK2) in nociceptors can produce long-lasting neuroplastic changes in nociceptor function, eventually enhancing and prolonging inflammatory hyperalgesia. Here, we investigated the effects of selective α2-adrenoceptor agonist dexmedetomidine (DMED) on GRK2 expression in superior cervical ganglion (SCG) in a rat model of complex regional pain syndrome type I (CRPS-I). The ipsilateral 50% paw withdrawal thresholds (PWTs) to mechanical stimuli decreased significantly starting from 24 h after ischemia-reperfusion (I/R) injury, and lasted for over 3 weeks; the ipsilateral cold allodynia scores, GRK2 protein and mRNA levels in SCGs all increased significantly. No significant differences were found in the contralateral side except GRK2 mRNA reduced significantly after 48 h I/R injury, but still higher than those in the ipsilateral side. Following daily injection of 10 μg/kg of DMED for a maximum of 7 days, the ipsilateral PWTs on days 1, 2, 7, 14, and 21 after DMED administration were significantly higher than those in control group; the GRK2 protein and mRNA expressions in the ipsilateral SCGs were also significantly upregulated; the ipsilateral cold allodynia scores were significantly reduced. No significant differences were found in the contralateral 50%PWTs, cold allodynia scores, and GRK2 protein level except GRK2 mRNA levels increased significantly on days 1 to 7 after DMED administration. Therefore, a transient decrease of GRK2 expression in SCG neurons might be involved in the development and maintenance of allodynia in CRPS-I and DMED might alleviate this allodynia through GRK2 upregulation in SCG neurons.
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Affiliation(s)
- Jing Dong
- Department of Anesthesiology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Department of Anesthesiology, Shanghai First People's Hospital, Shanghai Jiaotong University affiliated Shanghai First People's Hospital, Shanghai 201620, China.
| | - Li Yang
- Department of Anesthesiology, Jinshan Hospital, Fudan University, Shanghai, China.
| | - Jun Tang
- Department of Anesthesiology, Jinshan Hospital, Fudan University, Shanghai, China.
| | - Jijian Zheng
- Department of Anesthesiology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Department of Anesthesiology, Shanghai First People's Hospital, Shanghai Jiaotong University affiliated Shanghai First People's Hospital, Shanghai 201620, China.
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Chabot-Doré AJ, Schuster DJ, Stone LS, Wilcox GL. Analgesic synergy between opioid and α2 -adrenoceptors. Br J Pharmacol 2014; 172:388-402. [PMID: 24641506 DOI: 10.1111/bph.12695] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 03/08/2014] [Accepted: 03/12/2014] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Opioid and α2 -adrenoceptor agonists are potent analgesic drugs and their analgesic effects can synergize when co-administered. These supra-additive interactions are potentially beneficial clinically; by increasing efficacy and/or reducing the total drug required to produce sufficient pain relief, undesired side effects can be minimized. However, combination therapies of opioids and α2 -adrenoceptor agonists remain underutilized clinically, in spite of a large body of preclinical evidence describing their synergistic interaction. One possible obstacle to the translation of preclinical findings to clinical applications is a lack of understanding of the mechanisms underlying the synergistic interactions between these two drug classes. In this review, we provide a detailed overview of the interactions between different opioid and α2 -adrenoceptor agonist combinations in preclinical studies. These studies have identified the spinal cord as an important site of action of synergistic interactions, provided insights into which receptors mediate these interactions and explored downstream signalling events enabling synergy. It is now well documented that the activation of both μ and δ opioid receptors can produce synergy with α2 -adrenoceptor agonists and that α2 -adrenoceptor agonists can mediate synergy through either the α2A or the α2C adrenoceptor subtypes. Current hypotheses surrounding the cellular mechanisms mediating opioid-adrenoceptor synergy, including PKC signalling and receptor oligomerization, and the evidence supporting them are presented. Finally, the implications of these findings for clinical applications and drug discovery are discussed. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- A-J Chabot-Doré
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
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Epidermal adrenergic signaling contributes to inflammation and pain sensitization in a rat model of complex regional pain syndrome. Pain 2013; 154:1224-36. [PMID: 23718987 DOI: 10.1016/j.pain.2013.03.033] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 03/07/2013] [Accepted: 03/26/2013] [Indexed: 02/08/2023]
Abstract
In many patients, the sympathetic nervous system supports pain and other features of complex regional pain syndrome (CRPS). Accumulating evidence suggests that interleukin (IL)-6 also plays a role in CRPS, and that catecholamines stimulate production of IL-6 in several tissues. We hypothesized that norepinephrine acting through specific adrenergic receptors expressed on keratinocytes stimulates the production of IL-6 and leads to nociceptive sensitization in a rat tibial fracture/cast model of CRPS. Our approach involved catecholamine depletion using 6-hydroxydopamine or, alternatively, guanethidine, to explore sympathetic contributions. Both agents substantially reduced nociceptive sensitization and selectively reduced the production of IL-6 in skin. Antagonism of IL-6 signaling using TB-2-081 also reduced sensitization in this model. Experiments using a rat keratinocyte cell line demonstrated relatively high levels of β2-adrenergic receptor (β2-AR) expression. Stimulation of this receptor greatly enhanced IL-6 expression when compared to the expression of IL-1β, tumor necrosis factor (TNF)-α, or nerve growth factor. Stimulation of the cells also promoted phosphorylation of the mitogen-activated protein kinases P38, extracellular signal-regulated kinase, and c-Jun amino-terminal kinase. Based on these in vitro results, we returned to animal testing and observed that the selective β2-AR antagonist butoxamine reduced nociceptive sensitization in the CRPS model, and that local injection of the selective β2-AR agonist terbutaline resulted in mechanical allodynia and the production of IL-6 in the cells of the skin. No increases in IL-1β, TNF-α, or nerve growth factor levels were seen, however. These data suggest that in CRPS, norepinephrine released from sympathetic nerve terminals stimulates β2-ARs expressed on epidermal keratinocytes, resulting in local IL-6 production, and ultimately, pain sensitization.
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The effect of progesterone on expression and development of neuropathic pain in a rat model of peripheral neuropathy. Eur J Pharmacol 2013; 699:207-12. [DOI: 10.1016/j.ejphar.2012.11.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 11/27/2012] [Accepted: 11/28/2012] [Indexed: 11/23/2022]
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Bataille C, Mauprivez C, Haÿ E, Baroukh B, Brun A, Chaussain C, Marie PJ, Saffar JL, Cherruau M. Different sympathetic pathways control the metabolism of distinct bone envelopes. Bone 2012; 50:1162-72. [PMID: 22326888 DOI: 10.1016/j.bone.2012.01.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 01/16/2012] [Accepted: 01/25/2012] [Indexed: 10/14/2022]
Abstract
Bone remodeling, the mechanism that modulates bone mass adaptation, is controlled by the sympathetic nervous system through the catecholaminergic pathway. However, resorption in the mandible periosteum envelope is associated with cholinergic Vasoactive Intestinal Peptide (VIP)-positive nerve fibers sensitive to sympathetic neurotoxics, suggesting that different sympathetic pathways may control distinct bone envelopes. In this study, we assessed the role of distinct sympathetic pathways on rat femur and mandible envelopes. To this goal, adult male Wistar rats were chemically sympathectomized or treated with agonists/antagonists of the catecholaminergic and cholinergic pathways; femora and mandibles were sampled. Histomorphometric analysis showed that sympathectomy decreased the number of preosteoclasts and RANKL-expressing osteoblasts in mandible periosteum but had no effect on femur trabecular bone. In contrast, pharmacological stimulation or repression of the catecholaminergic cell receptors impacted the femur trabecular bone and mandible endosteal retromolar zone. VIP treatment of sympathectomized rats rescued the disturbances of the mandible periosteum and alveolar wall whereas the cholinergic pathway had no effect on the catecholaminergic-dependent envelopes. We also found that VIP receptor-1 was weakly expressed in periosteal osteoblasts in the mandible and was increased by VIP treatment, whereas osteoblasts of the retromolar envelope that was innervated only by tyrosine hydroxylase-immunoreactive fibers, constitutively expressed beta-2 adrenergic receptors. These data highlight the complexity of the sympathetic control of bone metabolism. Both the embryological origin of the bone (endochondral for the femur, membranous for the mandibular periosteum and the socket wall) and environmental factors specific to the innervated envelope may influence the phenotype of the sympathetic innervation. We suggest that an origin-dependent imprint of bone cells through osteoblast-nerve interactions determines the type of autonomous system innervating a particular bone envelope.
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Affiliation(s)
- Caroline Bataille
- EA2496 Laboratoire Pathologies et Biothérapies de l'Organe Dentaire, Faculté de Chirurgie Dentaire, Université Paris Descartes, Sorbonne Paris Cité, 1 rue Maurice Arnoux 92120 Montrouge, France.
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Wang YJ, Li XF, Ding F, Shu Q, Song LJ, Yu X, Liu HX. Noradrenaline regulates substance P release from rat dorsal root ganglion neurons in vitro. Neurosci Bull 2012; 27:300-6. [PMID: 21934725 DOI: 10.1007/s12264-011-1034-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE To determine whether activation and/or inhibition of α-adrenoreceptors influences substance P (SP) release from dorsal root ganglion (DRG) primary sensory neurons in vitro. METHODS DRGs were dissected from 15-day embryonic Wistar rats. DRG neurons were dissociated and cultured for 2 d and then exposed to noradrenaline (NA) alone (1×10(-4) mol/L), or along with the α1-adrenoreceptor antagonist prazosin (1×10(-6) mol/L) or the α2-adrenoreceptor antagonist yohimbine (1×10(-5) mol/L) for 4 d. Then, RT-PCR was used to determine the levels of preprotachykinin (PPT) mRNA encoding for SP and Western blot to assess the protein levels of SP. Basal and capsaicin (CAP)-evoked SP release were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS CAP-evoked SP release was sensitized by NA and this effect was inhibited by pre-incubation with prazosin but not with yohimbine. The levels of PPT mRNA, SP peptide, and basal SP release did not change significantly in any of the experimental conditions. CONCLUSION NA may significantly increase CAP-evoked SP release through activation of α-adrenoreceptors, which may contribute to noradrenergic pain modulation.
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Affiliation(s)
- Yan-Jie Wang
- Department of Rheumatology, Shandong University Qilu Hospital, Jinan 250012, China
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Ethosuximide reduces allodynia and hyperalgesia and potentiates morphine effects in the chronic constriction injury model of neuropathic pain. Eur J Pharmacol 2012; 674:260-4. [DOI: 10.1016/j.ejphar.2011.11.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 11/05/2011] [Accepted: 11/10/2011] [Indexed: 11/21/2022]
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Abstract
STUDY DESIGN A narrative description highlighting preclinical and clinical evidence that physiologic stress systems contribute to whiplash-associated disorders (WAD) pathogenesis. OBJECTIVE To present several lines of evidence supporting the hypothesis that physiologic stress systems contribute to WAD pathogenesis. SUMMARY OF BACKGROUND DATA In addition to subjecting soft tissue to biomechanical strain, a motor vehicle collision (MVC) event is also an acute stressor which activates physiologic stress systems. Increasing data from animal and human studies suggest that the activation of these stress systems may contribute to long-lasting changes in pain sensitivity after tissue injury. METHODS Nonsystematic review of several lines of evidence that together suggest that physiologic systems involved in the stress response may contribute to the development of WAD. RESULTS Stress systems which appear capable of producing hyperalgesia and allodynia include catecholaminergic systems, serotonin systems, and the hypothalamic-pituitary-adrenocortical system. Evidence for the role of these systems comes, in part, from studies examining the association between genetic variants and chronic pain outcomes. For example, in a recent study of acute neck pain after MVC, patients with certain genotypes of an enzyme involved in catecholamine metabolism were more than twice as likely to report moderate or severe neck pain in the emergency department. Such pain vulnerability because of stress system function may interact with the effects of biomechanical injury and psychobehavioral responses to influence the development of WAD. CONCLUSION More research examining the influence of stress systems on WAD are needed. If these systems do influence WAD outcomes, then treatments which diminish the adverse effects of stress systems may be a useful component of multimodal therapeutic interventions for individuals at risk of chronic pain development after MVC.
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A peripheral adrenoceptor-mediated sympathetic mechanism can transform stress-induced analgesia into hyperalgesia. Anesthesiology 2011; 114:1403-16. [PMID: 21540738 DOI: 10.1097/aln.0b013e31821c3878] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Stress has paradoxical effects on pain, causing stress-induced analgesia but also exacerbating pain via poorly understood mechanisms. Adrenergic neurotransmission is integral in pathways that regulate the response to both pain and stress. Hyperalgesia is often associated with enhanced adrenergic sensitivity of primary afferents, but sympathetic nervous system outflow has not been demonstrated to exacerbate pain perception after stress. METHODS Rats or C57/BL6 wild-type mice treated with α-2 receptor antagonists or α-2A receptor knockout mice were exposed to ultrasonic noise stress or footshock stress and subsequently tested for hotplate paw withdrawal latencies. The sensory sensitivity of α-2A knockout mice to electrical and chemical stimuli was tested neurophysiologically and behaviorally. The effects of sympatholytic treatments were investigated. RESULTS Noise and footshock stressors induced thermal hyperalgesia in rats pretreated systemically with α-2 antagonists. Wild-type mice pretreated with α-2 antagonists and α-2A knockout mice also exhibited thermal hyperalgesia induced by noise stress. Local spinal or intraplantar injection of an α-2 antagonist counteracted stress-induced analgesia without causing hyperalgesia. The α-2A knockout mice had decreased thresholds for peripheral sensitization with sulprostone and for windup of the dorsal horn neuronal response to repetitive electrical stimuli. Stress-induced hyperalgesia was abolished and the sensitization was attenuated by sympathectomy or systemic administration of an α-1-adrenergic antagonist. CONCLUSIONS Sympathetic postganglionic nerves can enhance pain sensation via a peripheral α-1-adrenoceptor mechanism when sympathetic outflow is disinhibited. The net effect of stress on pain sensation reflects a balance between descending spinal inhibition and sympathetic outflow that can shift toward pain facilitation when central and peripheral α-2-adrenoceptor inhibitory mechanisms are attenuated.
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Zhang Q, Tan Y. Nerve growth factor augments neuronal responsiveness to noradrenaline in cultured dorsal root ganglion neurons of rats. Neuroscience 2011; 193:72-9. [PMID: 21784134 DOI: 10.1016/j.neuroscience.2011.07.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 07/09/2011] [Accepted: 07/12/2011] [Indexed: 11/28/2022]
Abstract
Increasing evidence indicates that both the nerve growth factor (NGF) and adrenergic systems play a very important role in the development of nociception. However, there is little information concerning the functional interactions between these two systems in the dorsal root ganglion (DRG). The present study tested the hypothesis that NGF could affect neuronal responsiveness to noradrenaline (NA) on the nociceptive DRG neurons, thus enhancing the nociceptive signals. To investigate this issue, spontaneous action potentials were recorded in cultured DRG neurons using current-clamp recording. When NGF (50 ng/ml, 24 h) was administered in the neuronal cultures, the neuronal firing response to NA (10 μM) was augmented in TrkA-positive neurons (3.02±0.28 Hz with NGF treatment vs. 1.36±0.14 Hz in control, P<0.05), indicating that chronic NGF treatment significantly enhanced the neuronal response to NA. Pretreatment of neurons with either the α-adrenergic receptor (AR) antagonist phentolamine (100 μM) or α1-AR antagonist prazosin (50 μM) significantly inhibited the enhanced firings of DRG neurons induced by NA. In addition, treatment of neuronal cultures with NGF (50 ng/ml, 24 h) induced a two-fold increase in α1b-AR expression, as detected with real-time reverse transcription PCR (RT-PCR) and Western blots, but had no effect on α2-AR expression. These observations indicate that NGF augmented neuronal responsiveness to NA in DRG neurons via increasing α1b-AR expression, and this could contribute to the development of pain sensitization.
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Affiliation(s)
- Q Zhang
- Basic Medical College, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, PR China.
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Chan AKM, Cheung CW, Chong YK. Alpha-2 agonists in acute pain management. Expert Opin Pharmacother 2010; 11:2849-68. [DOI: 10.1517/14656566.2010.511613] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Xu B, Zhang WS, Yang JL, Lû N, Deng XM, Xu H, Zhang YQ. Evidence for suppression of spinal glial activation by dexmedetomidine in a rat model of monoarthritis. Clin Exp Pharmacol Physiol 2010; 37:e158-66. [DOI: 10.1111/j.1440-1681.2010.05426.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Park CH, Yong A, Lee SH. Involvement of selective alpha-2 adrenoreceptor in sympathetically maintained pain. J Korean Neurosurg Soc 2010; 47:420-3. [PMID: 20617085 DOI: 10.3340/jkns.2010.47.6.420] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 04/28/2010] [Accepted: 05/23/2010] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Peripheral nerve injury often leads to neuropathic pain, which is characterized by burning pain, allodynia, and hyperalgesia. The role of the sympathetic nervous system in neuropathic pain is a complex and controversial issue. It is generally accepted that the alpha adrenoreceptor (AR) in sympathetic nerve system plays a significant role in the maintenance of pain. Among alpha adrenoreceptor, alpha-1 receptors play a major role in the sympathetic mediated pain. The primary goal of this study is to test the hypothesis that sympathetically maintained pain involves peripheral alpha-2 receptors in human. METHODS The study was a randomized, prospective, double-blinded, crossover study involving twenty patients. The treatments were : Yohimbine (30 mg mixed in 500 mL normal saline), and Phentolamine (1 mg/kg in 500 mL normal saline) in 500 mL normal saline at 70 mL/hr initially then titrated. The patients underwent infusions on three different appointments, at least one month apart. Thus, all patients received all 2 treatments. Pain measurement was by visual analogue scale, neuropathic pain questionnaire, and McGill pain questionnaire. RESULTS There were significant decreases in the visual analogue scale, neuropathic score, McGill pain score of yohimnine, and phentolamine. CONCLUSION We conclude that alpha-2 adrenoreceptor, along with alpha-2 adrenoreceptor, may be play role in sympathetically maintained pain in human.
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Affiliation(s)
- Chan Hong Park
- Department of Anesthesiology and Pain Medicine, Daegu Wooridul Hospital, Daegu, Korea
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Shieh JP, Chu CC, Wang JJ, Lin MT. Epinephrine, phenylephrine, and methoxamine induce infiltrative anesthesia via alpha1-adrenoceptors in rats. Acta Pharmacol Sin 2009; 30:1227-36. [PMID: 19730427 DOI: 10.1038/aps.2009.129] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
AIM To assess whether epinephrine, phenylephrine, and methoxamine act via certain subtypes of adrenoceptors to exert their local anesthetic activity. METHODS We investigated cutaneous anesthesia from adrenoceptor agonists and/or antagonists in conscious, unanesthetized Sprague-Dawley male rats (weight 200-250 g). Cutaneous anesthesia was evidenced by a block of the cutaneous trunci muscle reflex, which is characterized by reflex movement of the skin over the back produced by twitches of lateral thoracispinal muscles in response to local dorsal cutaneous noxious pinprick. RESULTS Local infiltration of epinephrine, L-phenylephrine, or methoxamine alone induces cutaneous anesthesia in rats in a dose-dependent way. Epinephrine is found to be 19 and 29 times more potent than those of methoxamine and L-phenylephrine, respectively. The cutaneous anesthesia induced by epinephrine, phenylephrine, or methoxamine can be significantly reduced by alpha(1)-adrenoceptor antagonists (eg, prazosin), alpha1, alpha2-adrenoceptor antagonist, alpha(1A)-adrenoceptor antagonist (eg, 5-methylurapdil), alpha(1B)-adrenoceptor antagonist (eg, chloroethylclonidine), or alpha(1D)-adrenoceptor antagonist (eg, BMY7873). CONCLUSION Our results indicate that epinephrine, phenylephrine and methoxamine all act mainly via mixed subtypes of alpha(1)-adrenoceptors to induce cutaneous anesthesia in the rat.
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Fairbanks CA, Stone LS, Wilcox GL. Pharmacological profiles of alpha 2 adrenergic receptor agonists identified using genetically altered mice and isobolographic analysis. Pharmacol Ther 2009; 123:224-38. [PMID: 19393691 DOI: 10.1016/j.pharmthera.2009.04.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 04/09/2009] [Indexed: 12/24/2022]
Abstract
Endogenous, descending noradrenergic fibers impose analgesic control over spinal afferent circuitry mediating the rostrad transmission of pain signals. These fibers target alpha 2 adrenergic receptors (alpha(2)ARs) on both primary afferent terminals and secondary neurons, and their activation mediates substantial inhibitory control over this transmission, rivaling that of opioid receptors which share a similar pattern of distribution. The terminals of primary afferent nociceptive neurons and secondary spinal dorsal horn neurons express alpha(2A)AR and alpha(2C)AR subtypes, respectively. Spinal delivery of these agents serves to reduce their side effects, which are mediated largely at supraspinal sites, by concentrating the drugs at the spinal level. Targeting these spinal alpha(2)ARs with one of five selective therapeutic agonists, clonidine, dexmedetomidine, brimonidine, ST91 and moxonidine, produces significant antinociception that can work in concert with opioid agonists to yield synergistic antinociception. Application of several genetically altered mouse lines had facilitated identification of the primary receptor subtypes that likely mediate the antinociceptive effects of these agents. This review provides first an anatomical description of the localization of the three subtypes in the central nervous system, second a detailed account of the pharmacological history of each of the six primary agonists, and finally a comprehensive report of the specific interactions of other GPCR agonists with each of the six principal alpha(2)AR agonists featured.
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Affiliation(s)
- Carolyn A Fairbanks
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
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Antihyperalgesic effect of systemic dexmedetomidine and gabapentin in a rat model of monoarthritis. Brain Res 2009; 1264:57-66. [DOI: 10.1016/j.brainres.2009.01.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 01/19/2009] [Accepted: 01/20/2009] [Indexed: 11/23/2022]
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Giovannoni MP, Ghelardini C, Vergelli C, Dal Piaz V. α2-Agonists as analgesic agents. Med Res Rev 2009; 29:339-68. [DOI: 10.1002/med.20134] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Yang X, Liu Z, Li Z. Effects of norepinephrine on galanin expression in dorsal root ganglion neurons in vitro. Curr Ther Res Clin Exp 2009; 70:19-28. [PMID: 24692829 DOI: 10.1016/j.curtheres.2009.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2008] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Norepinephrine (NE) is a key neurotransmitter that functionally activates adrenoreceptors expressed in sympathetic neurons. Functional α1-adrenoreceptors are also expressed in dorsal root ganglion (DRG) primary sensory neurons and regulate neurogenic inflammation and nociceptive responses. Galanin is involved in inflammation and nociception. It has been suggested that galanin receptor (GalR) 1 and GalR3 activation induces analgesia at the level of the spinal cord, while activation of GalR2 has a pronociceptive role in the periphery. Whether activation or inhibition of α-adrenoreceptors influences galanin expression remains unknown. OBJECTIVE The aim of the present study was to investigate whether the α-adrenoreceptor agonist NE, the α1-adrenoreceptor antagonist prazosin, and the α2-adrenoreceptor antagonist yohimbine affect galanin expression in primary cultured DRG neurons. METHODS DRG was dissected from 240 embryonic 15-day-old Wistar rats, cultured as dissociated cells for 2 days, and then exposed to NE (10(-4) mol/L) for another 4 days. In the NE + prazosin group and the NE + yohimbine group, DRG neurons were pretreated with prazosin (10(-6) mol/L) and yohimbine (10(-5) mol/L), respectively, 10 minutes prior to the NE challenge. The neurons cultured continuously in media served as the controls. All of the cultured samples were processed to detect galanin mRNA and galanin peptide expression by reverse transcriptase-polymerase chain reaction and Western blot, respectively. Five samples were tested for each procedure. RESULTS Forty samples were prepared for this study and included in the analysis. After 4 days of incubation, mean (SD) galanin mRNA/β-actin mRNA concentration ratio was significantly increased with NE compared with controls (0.3349 [0.0413] vs 0.2411 [0.0519]; P < 0.05). Pretreatment with prazosin seemed to block the effects of NE (0.2522 [0.0496]; P < 0.05 vs NE), while yohimbine did not appear to significantly alter the effects of NE on elevation of galanin mRNA/β-actin mRNA concentration (0.3154 [0.0239]; P < 0.05 vs controls). After 4 days of incubation, galanin/β-actin concentration ratio was significantly higher with NE compared with controls (0.4406 [0.0655] vs 0.2295 [0.0794]; P < 0.01). Pretreatment with prazosin appeared to inhibit NE-induced galanin peptide expression (0.3156 [0.0942]; P < 0.05 vs NE), while yohimbine did not appear to alter the effects of NE on elevation of galanin peptide concentration (0.3700 [0.0533]; P < 0.05 vs controls). Coclusions: In this small in vitro study, NE, likely due to action on α1-adrenoreceptors but not α2-adrenoreceptors, was associated with an increase in galanin mRNA concentration and galanin peptide expression in these DRG neurons. These findings might be relevant to noradrenergic pain modulation.
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Affiliation(s)
- Xiangdong Yang
- Department of Nephrology, Shandong University Qilu Hospital, Jinan, People's Republic of China
| | - Zhen Liu
- Department of Anatomy, Shandong University School of Medicine, Jinan, People's Republic of China
| | - Zhenzhong Li
- Department of Anatomy, Shandong University School of Medicine, Jinan, People's Republic of China
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Rahman W, D’Mello R, Dickenson AH. Peripheral Nerve Injury–Induced Changes in Spinal α2-Adrenoceptor–Mediated Modulation of Mechanically Evoked Dorsal Horn Neuronal Responses. THE JOURNAL OF PAIN 2008; 9:350-9. [DOI: 10.1016/j.jpain.2007.11.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 10/26/2007] [Accepted: 11/14/2007] [Indexed: 11/15/2022]
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Abstract
Pain research has uncovered important neuronal mechanisms that underlie clinically relevant pain states such as inflammatory and neuropathic pain. Importantly, both the peripheral and the central nociceptive system contribute significantly to the generation of pain upon inflammation and nerve injury. Peripheral nociceptors are sensitized during inflammation, and peripheral nerve fibres develop ectopic discharges upon nerve injury or disease. As a consequence a complex neuronal response is evoked in the spinal cord where neurons become hyperexcitable, and a new balance is set between excitation and inhibition. The spinal processes are significantly influenced by brain stem circuits that inhibit or facilitate spinal nociceptive processing. Numerous mechanisms are involved in peripheral and central nociceptive processes including rapid functional changes of signalling and long-term regulatory changes such as up-regulation of mediator/receptor systems. Conscious pain is generated by thalamocortical networks that produce both sensory discriminative and affective components of the pain response.
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Affiliation(s)
- H G Schaible
- Institut für Physiologie/Neurophysiologie, Teichgraben 8, 07740 Jena, Germany.
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Pertovaara A. Noradrenergic pain modulation. Prog Neurobiol 2006; 80:53-83. [PMID: 17030082 DOI: 10.1016/j.pneurobio.2006.08.001] [Citation(s) in RCA: 395] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 08/25/2006] [Accepted: 08/30/2006] [Indexed: 11/18/2022]
Abstract
Norepinephrine is involved in intrinsic control of pain. Main sources of norepinephrine are sympathetic nerves peripherally and noradrenergic brainstem nuclei A1-A7 centrally. Peripheral norepinephrine has little influence on pain in healthy tissues, whereas in injured tissues it has variable effects, including aggravation of pain. Its peripheral pronociceptive effect has been associated with injury-induced expression of novel noradrenergic receptors, sprouting of sympathetic nerve fibers, and pronociceptive changes in the ionic channel properties of primary afferent nociceptors, while an interaction with the immune system may contribute in part to peripheral antinociception induced by norepinephrine. In the spinal cord, norepinephrine released from descending pathways suppresses pain by inhibitory action on alpha-2A-adrenoceptors on central terminals of primary afferent nociceptors (presynaptic inhibition), by direct alpha-2-adrenergic action on pain-relay neurons (postsynaptic inhibition), and by alpha-1-adrenoceptor-mediated activation of inhibitory interneurons. Additionally, alpha-2C-adrenoceptors on axon terminals of excitatory interneurons of the spinal dorsal horn possibly contribute to spinal control of pain. At supraspinal levels, the pain modulatory effect by norepinephrine and noradrenergic receptors has varied depending on many factors such as the supraspinal site, the type of the adrenoceptor, the duration of the pain and pathophysiological condition. While in baseline conditions the noradrenergic system may have little effect, sustained pain induces noradrenergic feedback inhibition of pain. Noradrenergic systems may also contribute to top-down control of pain, such as induced by a change in the behavioral state. Following injury or inflammation, the central as well as peripheral noradrenergic system is subject to various plastic changes that influence its antinociceptive efficacy.
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Affiliation(s)
- Antti Pertovaara
- Biomedicum Helsinki, Institute of Biomedicine/Physiology, PO Box 63, University of Helsinki, FIN-00014 Helsinki, Finland.
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Yoshimura M, Furue H. Mechanisms for the Anti-nociceptive Actions of the Descending Noradrenergic and Serotonergic Systems in the Spinal Cord. J Pharmacol Sci 2006; 101:107-17. [PMID: 16766858 DOI: 10.1254/jphs.crj06008x] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
The sensation of pain plays a critical role as an alert and as a protection system against tissue damage from mechanical, chemical, and thermal stimuli. Despite the protective role of pain, the severity of pain sensation is markedly attenuated by the endogenous pain inhibitory systems that predominantly originate at the brain stem. Both behavioral and in vivo extracellular recording studies have sought the loci producing analgesia and clarification of the anti-nociceptive actions. Among those loci, the main descending systems to the spinal dorsal horn are noradrenergic and serotonergic. Although, in vivo studies have provided basic knowledge of these systems, the precise synaptic mechanisms underlying the analgesic actions have not yet been elucidated until recently. The newly developed in vitro slice and in vivo patch-clamp recordings have disclosed the synaptic mechanisms of the noradrenergic and serotonergic effects at the level of spinal dorsal horn. This paper reviews the anti-nociceptive action of these systems, while particularly focusing on the electrophysiological aspects of the systems at the single neuron level in the spinal dorsal horn as well as their origins and responsible receptor subtypes.
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Affiliation(s)
- Megumu Yoshimura
- Department of Integrative Physiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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Offley SC, Guo TZ, Wei T, Clark JD, Vogel H, Lindsey DP, Jacobs CR, Yao W, Lane NE, Kingery WS. Capsaicin-sensitive sensory neurons contribute to the maintenance of trabecular bone integrity. J Bone Miner Res 2005; 20:257-67. [PMID: 15647820 DOI: 10.1359/jbmr.041108] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Revised: 07/26/2004] [Accepted: 08/31/2004] [Indexed: 11/18/2022]
Abstract
UNLABELLED This investigation used capsaicin to selectively lesion unmyelinated sensory neurons in rats. Neuronal lesioning induced a loss of trabecular integrity, reduced bone mass and strength, and depleted neuropeptides in nerve and bone. These data suggest that capsaicin-sensitive sensory nerves contribute to trabecular bone integrity. INTRODUCTION Familial dysautomia is an autosomal recessive disease in which patients suffer from unmyelinated sensory neuron loss, reduced BMD, and frequent fractures. It has been proposed that the loss of neurotransmitters synthesized by unmyelinated neurons adversely affects bone integrity in this hereditary syndrome. The purpose of this study was to determine whether small sensory neurons are required for the maintenance of bone integrity in rats. MATERIALS AND METHODS Ten-month-old male Sprague-Dawley rats were treated with either capsaicin or vehicle. In vivo DXA scanning and micro CT scanning, and histomorphometry were used to evaluate BMD, structure, and cellular activity. Bone strength was measured in distal femoral sections. Body weight and gastrocnemius/soleus weights were measured and spontaneous locomotor activity was monitored. Peroneal nerve morphometry was evaluated using light and electron microscopy. Substance P and calcitonin gene-related peptide (CGRP) content in the sciatic nerve and proximal tibia were determined by enzyme immunoassay (EIA). Substance P signaling was measured using a sciatic nerve stimulation extravasation assay. RESULTS Four weeks after capsaicin treatment, there was a loss of BMD in the metaphyses of the tibia and femur. In the proximal tibia, the osteoclast number and surface increased, osteoblast activity and bone formation were impaired, and trabecular bone volume and connectivity were diminished. There was also a loss of bone strength in the distal femur. No changes occurred in body weight, 24-h grid-crossing activity, weight bearing, or muscle mass after capsaicin treatment, indicating that skeletal unloading did not contribute to the loss of bone integrity. Capsaicin treatment destroyed 57% of the unmyelinated sensory axons, reduced the substance P and CGRP content in the sciatic nerve and proximal tibia, and inhibited neurogenic extravasation. CONCLUSION These results support the hypothesis that capsaicin-sensitive sensory neurons contribute to the maintenance of trabecular bone integrity. Capsaicin-sensitive neurons have efferent functions in the tissues they innervate, effects mediated by transmitters released from the peripheral nerve terminals. We postulate that the deleterious effects of capsaicin treatment on trabecular bone are mediated by reductions in local neurotransmitter content and release.
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Affiliation(s)
- Sarah C Offley
- Physical Medicine and Rehabilitation Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA
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Abstract
The biological effects of epinephrine and norepinephrine are mediated via 9 different adrenergic receptor subtypes, which all belong to the superfamily of G protein-coupled receptors. Although pharmacological ligands for adrenergic receptors have an important place in medical therapy, the full therapeutic potential of the 9 adrenergic receptor subtypes has not been explored yet. To dissect the physiological relevance of adrenergic receptor subtype diversity, gene-targeted mouse models carrying deletions in these receptor genes ("knockout mice") have been generated. This review gives an overview of the phenotypes observed in mice deficient in adrenergic receptors and discusses the therapeutic relevance of subtype-specific drug therapy.
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MESH Headings
- Animals
- Mice
- Mice, Knockout
- Models, Animal
- Receptors, Adrenergic, alpha/genetics
- Receptors, Adrenergic, alpha/physiology
- Receptors, Adrenergic, beta/genetics
- Receptors, Adrenergic, beta/physiology
- Signal Transduction/physiology
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Affiliation(s)
- Melanie Philipp
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Strasse 9, D-97078, Würzburg, Germany
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Schaible HG, Richter F. Pathophysiology of pain. Langenbecks Arch Surg 2004; 389:237-43. [PMID: 15034717 DOI: 10.1007/s00423-004-0468-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Accepted: 01/20/2004] [Indexed: 12/18/2022]
Abstract
Pain is a major symptom of many different diseases. Modern pain research has uncovered important neuronal mechanisms that are underlying clinically relevant pain states, and research goes on to define different types of pains on the basis of their neuronal and molecular mechanisms. This review will briefly outline neuronal mechanisms of pathophysiological nociceptive pain resulting from inflammation and injury, and neuropathic pain resulting from nerve damage. Pain is the sensation that is specifically evoked by potential or actual noxious (i.e. tissue damaging) stimuli or by tissue injury. Pain research has not only explored the neuronal and molecular basis of the "pain system" of the healthy subject but has also provided insights into the function and plasticity of the "pain system" during clinically relevant pains such as post-injury pain, inflammatory pain, postoperative pain, cancer pain and neuropathic pain. This review will briefly describe the "pain system" and then address neuronal mechanisms that are involved in clinical pain states.
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Affiliation(s)
- Hans-Georg Schaible
- Institut für Physiologie, Friedrich-Schiller-Universität Jena, Teichgraben 8, 07740 Jena, Germany.
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Sasaki A, Takasaki I, Andoh T, Nojima H, Shiraki K, Kuraishi Y. Roles of alpha-adrenoceptors and sympathetic nerve in acute herpetic pain induced by herpes simplex virus inoculation in mice. J Pharmacol Sci 2003; 92:329-36. [PMID: 12939517 DOI: 10.1254/jphs.92.329] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Percutaneous inoculation with herpes simplex virus type-1 brings about herpes zoster-like skin lesions, tactile allodynia, and mechanical hyperalgesia in mice. This study was conducted to determine whether the sympathetic nervous system and alpha-adrenoceptors would be involved in these pain-related responses and whether the alpha(2)-adrenoceptor agonist clonidine would suppress these responses. The adrenergic neuron blocker guanethidine and the non-selective alpha-adrenoceptor antagonist phentolamine did not affect the pain-related responses, although these agents suppressed the pain-related responses induced by partial ligation of the sciatic nerve. The pain-related responses induced by herpetic inoculation was suppressed by intraperitoneal and intrathecal injections, but not by intraplantar and intracerebroventricular injections, of clonidine. The suppressive effect of an intraperitoneal injection of clonidine (0.1 mg/kg) was antagonized by intrathecal injections of phentolamine and the alpha(2)-adrenoceptor antagonist yohimbine, but not the alpha(1)-adrenoceptor antagonist prazosin. The results suggest that sympathetic nerves and alpha-adrenoceptors are not involved in the pain-related responses induced by herpetic infection. Clonidine suppresses the responses probably through the action on alpha(2)-adrenoceptors in the dorsal horn.
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Affiliation(s)
- Atsushi Sasaki
- Department of Applied Pharmacology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Toyama, Japan
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Lähdesmäki J, Scheinin M, Pertovaara A, Mansikka H. The alpha2A-adrenoceptor subtype is not involved in inflammatory hyperalgesia or morphine-induced antinociception. Eur J Pharmacol 2003; 468:183-9. [PMID: 12754056 DOI: 10.1016/s0014-2999(03)01677-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The purpose of the present study was to investigate the role of the alpha(2A)-adrenoceptor subtype in inflammatory hyperalgesia, and in adrenergic-mu-opioid interactions in acute pain and inflammatory hyperalgesia. Behavioral responses to mechanical and thermal stimuli were studied in alpha(2A)-adrenoceptor knockout mice and their wild-type controls. Thermal nociception was evaluated as paw withdrawal latencies to radiant heat applied to the hindpaws. Mechanical nociception was measured using von Frey monofilament applications to the hindpaws. Mechanical and thermal hyperalgesia, induced with intraplantar carrageenan (1 mg/40 microl) were compared in alpha(2A)-adrenoceptor knockout and wild-type mice. The effects of the systemically administered mu-opioid receptor agonist morphine (1-10 mg/kg) were evaluated on mechanical withdrawal responses under normal and inflammatory conditions in knockout and wild-type mice. Withdrawal responses to radiant heat and von Frey monofilaments were similar in alpha(2A)-adrenoceptor knockout and wild-type mice before and after the carrageenan-induced hindpaw inflammation. Also, the antinociceptive effects of morphine in mechanical nociceptive tests were similar before and after carrageenan-induced hindpaw inflammation. Our observations indicate that alpha(2A)-adrenoceptors are not tonically involved in the modulation of inflammation-induced mechanical and thermal hyperalgesia. In addition, alpha(2A)-adrenoceptors do not appear to play an important role in mu-opioid receptor-mediated antinociception or antihyperalgesia.
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Affiliation(s)
- Janne Lähdesmäki
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Turku, Finland
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Abstract
Acute nociceptive, inflammatory, and neuropathic pain all depend to some degree on the peripheral activation of primary sensory afferent neurons. The localized peripheral administration of drugs, such as by topical application, can potentially optimize drug concentrations at the site of origin of the pain, while leading to lower systemic levels and fewer adverse systemic effects, fewer drug interactions, and no need to titrate doses into a therapeutic range compared with systemic administration. Primary sensory afferent neurons can be activated by a range of inflammatory mediators such as prostanoids, bradykinin, ATP, histamine, and serotonin, and inhibiting their actions represents a strategy for the development of analgesics. Peripheral nerve endings also express a variety of inhibitory neuroreceptors such as opioid, alpha-adrenergic, cholinergic, adenosine and cannabinoid receptors, and agonists for these receptors also represent viable targets for drug development. At present, topical and other forms of peripheral administration of nonsteroidal anti-inflammatory drugs, opioids, capsaicin, local anesthetics, and alpha-adrenoceptor agonists are being used in a variety of clinical states. There also are some clinical data on the use of topical antidepressants and glutamate receptor antagonists. There are preclinical data supporting the potential for development of local formulations of adenosine agonists, cannabinoid agonists, cholinergic ligands, cytokine antagonists, bradykinin antagonists, ATP antagonists, biogenic amine antagonists, neuropeptide antagonists, and agents that alter the availability of nerve growth factor. Given that activation of sensory neurons involves multiple mediators, combinations of agents targeting different mechanisms may be particularly useful. Topical analgesics represent a promising area for future drug development.
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Affiliation(s)
- Jana Sawynok
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada.
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Wei H, Jyväsjärvi E, Niissalo S, Hukkanen M, Waris E, Konttinen YT, Pertovaara A. The influence of chemical sympathectomy on pain responsivity and alpha 2-adrenergic antinociception in neuropathic animals. Neuroscience 2002; 114:655-68. [PMID: 12220567 DOI: 10.1016/s0306-4522(02)00328-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We studied the effect of chemical sympathectomy by 6-hydroxydopamine (6-OHDA) on pain behavior and alpha(2)-adrenergic antinociception in rats with a spinal nerve ligation-induced neuropathy. For assessment of alpha(2)-adrenergic antinociception, the rats were treated systemically with two alpha(2)-adrenoceptor agonists, one of which only poorly (MPV-2426) and the other very well (dexmedetomidine) penetrates the blood-brain barrier. Moreover, the effect of MPV-2426 on spontaneous activity of dorsal root nerve fibers proximal to the nerve injury was determined. Systemic treatment with 6-OHDA produced a marked decrease in immunocytochemical labeling of sympathetic nerve fibers in the skin but it produced no marked change in basal pain sensitivity to mechanical stimulation either in neuropathic or sham-operated animals. Systemic administration of MPV-2426 and dexmedetomidine produced a dose-dependent tactile antiallodynic effect in neuropathic animals. Intraplantar injection of MPV-2426 had an identical antiallodynic effect independent of whether it was injected into the neuropathic or contralateral hindpaw. In a test of mechanical nociception and hyperalgesia, dexmedetomidine markedly attenuated pain responses in all experimental groups, whereas MPV-2426 had a weak but significant pain attenuating effect only in neuropathic animals. In the tail flick test, both alpha(2)-adrenoceptor agonists had a significant antinociceptive effect. The pain attenuating effect of MPV-2426 was enhanced by pretreatment with 6-OHDA, except in a test of tactile allodynia. MPV-2426-induced modulation of spontaneous activity was not a general property of dorsal root fibers proximal to the injury. The results indicate that a chemical destruction of sympathetic postganglionic nerve fibers innervating the skin does not markedly influence cutaneous pain sensitivity nor is it critical for the alpha(2)-adrenoceptor agonist-induced attenuation of pain behavior in neuropathic or non-neuropathic animals. Chemical sympathectomy, independent of neuropathy, enhanced the pain attenuating effect by MPV-2426, probably due to a peripheral action, whereas in non-sympathectomized control and neuropathic animals peripheral mechanisms have only a minor, if any, role in the alpha(2)-adrenoceptor agonist-induced antinociception.
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Affiliation(s)
- H Wei
- Department of Physiology, Institute of Biomedicine, University of Helsinki, Helsinki, Finland
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Xiao HS, Huang QH, Zhang FX, Bao L, Lu YJ, Guo C, Yang L, Huang WJ, Fu G, Xu SH, Cheng XP, Yan Q, Zhu ZD, Zhang X, Chen Z, Han ZG, Zhang X. Identification of gene expression profile of dorsal root ganglion in the rat peripheral axotomy model of neuropathic pain. Proc Natl Acad Sci U S A 2002; 99:8360-5. [PMID: 12060780 PMCID: PMC123072 DOI: 10.1073/pnas.122231899] [Citation(s) in RCA: 417] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phenotypic modification of dorsal root ganglion (DRG) neurons represents an important mechanism underlying neuropathic pain. However, the nerve injury-induced molecular changes are not fully identified. To determine the molecular alterations in a broader way, we have carried out cDNA array on the genes mainly made from the cDNA libraries of lumbar DRGs of normal rats and of rats 14 days after peripheral axotomy. Of the 7,523 examined genes and expressed sequence tags (ESTs), the expression of 122 genes and 51 expressed sequence tags is strongly changed. These genes encompass a large number of members of distinct families, including neuropeptides, receptors, ion channels, signal transduction molecules, synaptic vesicle proteins, and others. Of particular interest is the up-regulation of gamma-aminobutyric acid(A) receptor alpha5 subunit, peripheral benzodiazepine receptor, nicotinic acetylcholine receptor alpha7 subunit, P2Y1 purinoceptor, Na(+) channel beta2 subunit, and L-type Ca(2+) channel alpha2delta-1 subunit. Our findings therefore reveal dynamic and complex changes in molecular diversity among DRG neurons after axotomy. Sequences reported in this paper have been deposited in the GenBank database (accession numbers BG 662484-BG 673712)
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Affiliation(s)
- Hua-Sheng Xiao
- Laboratory of Sensory System, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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Janssen BJA, Smits JFM. Autonomic control of blood pressure in mice: basic physiology and effects of genetic modification. Am J Physiol Regul Integr Comp Physiol 2002; 282:R1545-64. [PMID: 12010736 DOI: 10.1152/ajpregu.00714.2001] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Control of blood pressure and of blood flow is essential for maintenance of homeostasis. The hemodynamic state is adjusted by intrinsic, neural, and hormonal mechanisms to optimize adaptation to internal and environmental challenges. In the last decade, many studies showed that modification of the mouse genome may alter the capacity of cardiovascular control systems to respond to homeostatic challenges or even bring about a permanent pathophysiological state. This review discusses the progress that has been made in understanding of autonomic cardiovascular control mechanisms from studies in genetically modified mice. First, from a physiological perspective, we describe how basic hemodynamic function can be measured in conscious conditions in mice. Second, we focus on the integrative role of autonomic nerves in control of blood pressure in the mouse, and finally, we depict the opportunities and insights provided by genetic modification in this area.
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Affiliation(s)
- Ben J A Janssen
- Department of Pharmacology and Toxicology, Cardiovascular Research Institute Maastricht, Universiteit Maastricht, Maastricht, 6200 MD, The Netherlands.
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