1
|
Xue Y, Mo S, Li Y, Cao Y, Xu X, Xie Q. Dissecting neural circuits from rostral ventromedial medulla to spinal trigeminal nucleus bidirectionally modulating craniofacial mechanical sensitivity. Prog Neurobiol 2024; 232:102561. [PMID: 38142769 DOI: 10.1016/j.pneurobio.2023.102561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 11/24/2023] [Accepted: 12/15/2023] [Indexed: 12/26/2023]
Abstract
Chronic craniofacial pain is intractable and its mechanisms remain unclarified. The rostral ventromedial medulla (RVM) plays a crucial role in descending pain facilitation and inhibition. It is unclear how the descending circuits from the RVM to spinal trigeminal nucleus (Sp5) are organized to bidirectionally modulate craniofacial nociception. We used viral tracing, in vivo optogenetics, calcium signaling recording, and chemogenetic manipulations to investigate the structure and function of RVM-Sp5 circuits. We found that most RVM neurons projecting to Sp5 were GABAergic or glutamatergic and facilitated or inhibited craniofacial nociception, respectively. Both GABAergic interneurons and glutamatergic projection neurons in Sp5 received RVM inputs: the former were antinociceptive, whereas the latter were pronociceptive. Furthermore, we demonstrated activation of both GABAergic and glutamatergic Sp5 neurons receiving RVM inputs in inflammation- or dysfunction-induced masseter hyperalgesia. Activating GABAergic Sp5 neurons or inhibiting glutamatergic Sp5 neurons that receive RVM projections reversed masseter hyperalgesia. Our study identifies specific cell types and projections of RVM-Sp5 circuits involved in facilitating or inhibiting craniofacial nociception respectively. Selective manipulation of RVM-Sp5 circuits can be used as potential treatment strategy to relieve chronic craniofacial muscle pain.
Collapse
Affiliation(s)
- Yang Xue
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China
| | - Siyi Mo
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China
| | - Yuan Li
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China
| | - Ye Cao
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China.
| | - Xiaoxiang Xu
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China.
| | - Qiufei Xie
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China.
| |
Collapse
|
2
|
Raman S, Ikutame D, Okura K, Matsuka Y. Targeted Therapy for Orofacial Pain: A Novel Perspective for Precision Medicine. J Pers Med 2023; 13:jpm13030565. [PMID: 36983746 PMCID: PMC10057163 DOI: 10.3390/jpm13030565] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Orofacial pain (OFP) is a dental specialty that includes the diagnosis, management and treatment of disorders of the jaw, mouth, face, head and neck. Evidence-based understanding is critical in effectively treating OFPs as the pathophysiology of these conditions is multifactorial. Since OFP impacts the quality of life of the affected individuals, treating patients successfully is of the utmost significance. Despite the therapeutic choices available, treating OFP is still quite challenging, owing to inter-patient variations. The emerging trends in precision medicine could probably lead us to a paradigm shift in effectively managing the untreatable long-standing pain conditions. Precision medicine is designed based on the patient's genetic profile to meet their needs. Several significant relationships have been discovered based on the genetics and genomics of pain in the past, and some of the notable targets are discussed in this review. The scope of this review is to discuss preclinical and clinical trials that include approaches used in targeted therapy for orofacial pain. Future developments in pain medicine should benefit from current trends in research into novel therapeutic approaches.
Collapse
Affiliation(s)
- Swarnalakshmi Raman
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8504, Japan
| | - Daisuke Ikutame
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8504, Japan
| | - Kazuo Okura
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8504, Japan
| | - Yoshizo Matsuka
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8504, Japan
| |
Collapse
|
3
|
Morales-Medina JC, Pugliese N, Di Cerbo A, Zizzadoro C, Iannitti T. Evidence for Endogenous Opioid Dependence Related to Latent Sensitization in a Rat Model of Chronic Inflammatory Pain. Int J Mol Sci 2023; 24:ijms24032812. [PMID: 36769126 PMCID: PMC9917357 DOI: 10.3390/ijms24032812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
Studies performed in a mouse model of chronic inflammatory pain induced by intraplantar injection of complete Freund's adjuvant (CFA) have shown that constitutive activation of the endogenous opioid signaling, besides serving as a mechanism of endogenous analgesia that tonically represses pain sensitization, also generates a state of endogenous opioid dependence. Since species-related differences concerning pain biology and addictive behaviors occur between mice and rats, the present study explored whether the coexistence of endogenous opioid analgesia and endogenous opioid dependence also characterizes a homologous rat model. To this aim, CFA-injured Wistar rats were treated with either 3 mg/kg or 10 mg/kg of the opioid receptor inverse agonist naltrexone (NTX) during the pain remission phase and monitored for 60 min for possible withdrawal behaviors. At 3 mg/kg, NTX, besides inducing the reinstatement of mechanical allodynia, also caused a distinct appearance of ptosis, with slight but nonsignificant changes to the occurrence of teeth chatters and rearing. On the other hand, 10 mg/kg of NTX failed to unmask pain sensitization and induced significantly lower levels of ptosis than 3 mg/kg. Such an NTX-related response pattern observed in the rat CFA model seems to differ substantially from the pattern previously described in the mouse CFA model. This supports the knowledge that mice and rats are not identical in terms of pharmacological response and stresses the importance of choosing the appropriate species for preclinical pain research purposes depending on the scientific question being asked.
Collapse
Affiliation(s)
- Julio César Morales-Medina
- Centro de Investigación en Reproducción Animal, CINVESTAV-Universidad Autónoma de Tlaxcala, AP 62, Tlaxcala 90000, Mexico
| | - Nicola Pugliese
- Department of Veterinary Medicine, University of Bari, 70010 Valenzano, Italy
| | - Alessandro Di Cerbo
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Matelica, Italy
- Correspondence: (A.D.C.); (C.Z.)
| | - Claudia Zizzadoro
- Department of Veterinary Medicine, University of Bari, 70010 Valenzano, Italy
- Correspondence: (A.D.C.); (C.Z.)
| | - Tommaso Iannitti
- Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, Via Fossato di Mortara 70, 44121 Ferrara, Italy
| |
Collapse
|
4
|
Liu Q, He H, Mai L, Yang S, Fan W, Huang F. Peripherally Acting Opioids in Orofacial Pain. Front Neurosci 2021; 15:665445. [PMID: 34017236 PMCID: PMC8129166 DOI: 10.3389/fnins.2021.665445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/12/2021] [Indexed: 12/12/2022] Open
Abstract
The activation of opioid receptors by exogenous or endogenous opioids can produce significant analgesic effects in peripheral tissues. Numerous researchers have demonstrated the expression of peripheral opioid receptors (PORs) and endogenous opioid peptides (EOPs) in the orofacial region. Growing evidence has shown the involvement of PORs and immune cell-derived EOPs in the modulation of orofacial pain. In this review, we discuss the role of PORs and EOPs in orofacial pain and the possible cellular mechanisms involved. Furthermore, the potential development of therapeutic strategies for orofacial pain is also summarized.
Collapse
Affiliation(s)
- Qing Liu
- Department of Pediatric Dentistry, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Hongwen He
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China.,Department of Oral Anatomy and Physiology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Lijia Mai
- Department of Pediatric Dentistry, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Shengyan Yang
- Department of Pediatric Dentistry, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Wenguo Fan
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Fang Huang
- Department of Pediatric Dentistry, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| |
Collapse
|
5
|
Gonçalves WA, Ferreira RCM, Rezende BM, Mahecha GAB, Gualdron M, de Macedo FHP, Duarte IDG, Perez AC, Machado FS, Cruz JS, Romero TRL. Endogenous opioid and cannabinoid systems modulate the muscle pain: A pharmacological study into the peripheral site. Eur J Pharmacol 2021; 901:174089. [PMID: 33826922 DOI: 10.1016/j.ejphar.2021.174089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 11/16/2022]
Abstract
The participation of the peripheral opioid and cannabinoid endogenous systems in modulating muscle pain and inflammation has not been fully explored. Thus, the aim of this study was to investigate the involvement of these endogenous systems during muscular-tissue hyperalgesia induced by inflammation. Hyperalgesia was induced by carrageenan injection into the tibialis anterior muscles of male Wistar rats. We padronized an available Randal-Sellito test adaptation to evaluate nociceptive behavior elicited by mechanical insult in muscles. Western blot analysis was performed to evaluate the expression levels of opioid and cannabinoid receptors in the dorsal root ganglia. The non-selective opioid peptide receptor antagonist (naloxone) and the selective mu opioid receptor MOP (clocinnamox) and kappa opioid receptor KOP (nor-binaltorphimine) antagonists were able to intensify carrageenan-induced muscular hyperalgesia. On the other hand, the selective delta opioid receptor (DOP) antagonist (naltrindole) did not present any effect on nociceptive behavior. Moreover, the selective inhibitor of aminopeptidases (Bestatin) provoked considerable dose-dependent analgesia when intramuscularly injected into the hyperalgesic muscle. The CB1 receptor antagonist (AM251), but not the CB2 receptor antagonist (AM630), intensified muscle hyperalgesia. All irreversible inhibitors of anandamide hydrolase (MAFP), the inhibitor for monoacylglycerol lipase (JZL184) and the anandamide reuptake inhibitor (VDM11) decreased carrageenan-induced hyperalgesia in muscular tissue. Lastly, MOP, KOP and CB1 expression levels in DRG were baseline even after muscular injection with carrageenan. The endogenous opioid and cannabinoid systems participate in peripheral muscle pain control through the activation of MOP, KOP and CB1 receptors.
Collapse
Affiliation(s)
- William A Gonçalves
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Renata C M Ferreira
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Barbara M Rezende
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - German A B Mahecha
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Melissa Gualdron
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Flávio H P de Macedo
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Igor D G Duarte
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Andrea C Perez
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Fabiana S Machado
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Jader S Cruz
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
| | - Thiago R L Romero
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
| |
Collapse
|
6
|
Liu Q, Fan W, He H, Huang F. The role of peripheral opioid receptors in orofacial pain. Oral Dis 2020; 27:1106-1114. [PMID: 32437594 DOI: 10.1111/odi.13435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/04/2020] [Accepted: 05/12/2020] [Indexed: 12/20/2022]
Abstract
Opioid receptors are widely distributed in the central and peripheral nervous systems and non-neuronal tissues. Numerous researchers have noted the pivotal role of peripheral opioid receptors (PORs) in analgesia. Accumulating evidence has shown the existence of PORs in the trigeminal nerve system, indicating that PORs may be involved in the modulation of orofacial pain. In this review, we summarise the recent evidence for the role of PORs in orofacial pain and discuss the possible cellular mechanisms.
Collapse
Affiliation(s)
- Qing Liu
- Department of Pediatric Dentistry, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Wenguo Fan
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Hongwen He
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China.,Department of Oral Anatomy and Physiology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Fang Huang
- Department of Pediatric Dentistry, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| |
Collapse
|
7
|
Bagues A, Martín MI, Higuera-Matas A, Esteban-Hernández J, Ambrosio E, Sánchez-Robles EM. Mu-Opioid Receptors in Ganglia, But Not in Muscle, Mediate Peripheral Analgesia in Rat Muscle Pain. Anesth Analg 2019; 126:1369-1376. [PMID: 29261544 DOI: 10.1213/ane.0000000000002717] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Previous studies have demonstrated the participation of peripheral μ-opioid receptors (MOR) in the antinociceptive effect of systemically administered morphine and loperamide in an orofacial muscle pain model, induced by hypertonic saline, but not in a spinally innervated one, in rats. In this study, we determine whether this peripheral antinociceptive effect is due to the activation of MOR localized in the muscle, ganglia, or both. METHODS To determine the local antinociceptive effect of morphine and loperamide, 2 models of acute muscle pain (trigeminal and spinal) were used. Also, to study the MOR expression, protein quantification was performed in the trigeminal and spinal ganglia, and in the muscles. RESULTS The behavioral results show that the intramuscular injection of morphine and loperamide did not exert an antinociceptive effect in either muscle (morphine: P = .63, loperamide: P = .9). On the other hand, MOR expression was found in the ganglia but not in the muscles. This expression was on average 44% higher (95% confidence interval, 33.3-53.9) in the trigeminal ganglia than in the spinal one. CONCLUSIONS The peripheral antinociceptive effect of systemically administered opioids may be due to the activation of MOR in ganglia. The greater expression of MOR in trigeminal ganglia could explain the higher antinociceptive effect of opioids in orofacial muscle pain than in spinal muscle pain. Therefore, peripheral opioids could represent a promising approach for the treatment of orofacial pain.
Collapse
Affiliation(s)
| | | | - Alejandro Higuera-Matas
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | - Jesús Esteban-Hernández
- Área de Medicina Preventiva y Salud Pública, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Madrid, Spain
| | - Emilio Ambrosio
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | | |
Collapse
|
8
|
Zhang T, Zhao W, Zhang M, Xu B, Shi X, Zhang Q, Guo Y, Xiao J, Chen D, Zheng T, Fang Q. Analgesic activities of the mixed opioid and NPFF receptors agonist DN-9 in a mouse model of formalin-induced orofacial inflammatory pain. Peptides 2018; 110:30-39. [PMID: 30391423 DOI: 10.1016/j.peptides.2018.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 10/13/2018] [Accepted: 10/29/2018] [Indexed: 11/20/2022]
Abstract
Orofacial pain is one of the most common pain conditions and compromises the quality of life of the sufferer. Several studies have shown that opioid agonists produced significant analgesia in the orofacial pain, and combination of opioids with drugs belonging to other classes induced synergism in the orofacial pain. However, combination therapy of different analgesic drugs improves the risk of drug-drug interactions. Against this background, we sought to investigate the analgesic effects of the multi-functional opioid peptide DN-9, a mixed opioid and NPFF receptors agonist that produced robust analgesia in acute and inflammatory pain models, on formalin-induced orofacial pain. Our results showed that formalin injection caused significant spontaneous pain behaviors and increased the expressions of the mu-opioid receptor, c-Fos and phosphorylated extracellular signal-regulated kinase (p-ERK1/2) in the ipsilateral trigeminal ganglion (TG). In mice pretreated with DN-9, there was a significant reduction in nociceptive behaviors, which was selectively mediated by the mu- and kappa-opioid receptors, independently of the NPFF system. Four hours after formalin injection, the level of c-Fos immunoreactivity in the ipsilateral TG neurons was much lower in mice pretreated with DN-9 or morphine. In addition, DN-9 exhibited a significant inhibition in the expression of p-ERK1/2, which was reversed by the selective antagonists of the mu- and kappa-opioid receptors. In conclusion, our present results demonstrate that central administration of DN-9 produces potential antinociceptive effects via the mu- and kappa-opioid receptors, independently of the NPFF system, and this antinociceptive action is tightly linked with the intracellular ERK activation in TG neurons.
Collapse
Affiliation(s)
- Ting Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Weidong Zhao
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Mengna Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Biao Xu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Xuerui Shi
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Qinqin Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Yuanyuan Guo
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Jian Xiao
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Dan Chen
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China
| | - Ting Zheng
- Department of Clinical Medicine, Gansu Health Vocational College, 60 Donggang West Road, Lanzhou 730000, China
| | - Quan Fang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, China.
| |
Collapse
|
9
|
Kang SK, Lee YH, Park H, Ro JY, Auh QS. Effects of intramuscular morphine in men and women with temporomandibular disorder with myofascial pain. Oral Dis 2018; 24:1591-1598. [PMID: 29920852 DOI: 10.1111/odi.12919] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 05/30/2018] [Accepted: 06/08/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVES This placebo-controlled randomized double-blinded clinical study assessed the analgesic efficacy of intramuscular morphine in TMD patients with myofascial pain and sex-dependent responses of the morphine treatment. SUBJECTS AND METHODS Men and women with TMD were treated with morphine (1.5 or 5 mg), lidocaine, or saline in the masseter muscle. VAS of pain intensity, PPT, and PPtol were compared between treatment groups and gender. An additional group was treated with morphine in the trapezius muscle to evaluate the systemic effect of morphine that may reduce pain in the masseter muscle. RESULTS There was a significant difference in VAS scores between the morphine 5 mg group and the saline group favoring morphine, but not between the morphine 5 mg and lidocaine. Morphine 1.5 and 5 mg treatments led to consistently and significantly elevated PPT and PPtol measures in men, but not in women. Morphine administered in the trapezius muscle did not affect the outcome measures. CONCLUSION A single dose intramuscular morphine produced analgesic effects up to 48 hr in patients with myofascial pain. Intramuscular morphine elevated mechanical pain threshold and tolerance in the masseter only in male patients, suggesting sex differences in local morphine effects. No systemic effect of intramuscular morphine was detected.
Collapse
Affiliation(s)
- Soo-Kyung Kang
- Department of Oral Medicine, School of Dentistry, Kyung Hee University, Seoul, Korea
| | - Yeon-Hee Lee
- Department of Oral Medicine, School of Dentistry, Kyung Hee University, Seoul, Korea
| | - Hyeji Park
- Department of Dentistry, Graduate School, Kyung Hee University, Seoul, Korea
| | - Jin Y Ro
- Department of Oral Medicine, School of Dentistry, Kyung Hee University, Seoul, Korea.,Department of Neural and Pain Sciences, Program in Neuroscience, University of Maryland School of Dentistry, Baltimore, Maryland
| | - Q-Schick Auh
- Department of Oral Medicine, School of Dentistry, Kyung Hee University, Seoul, Korea
| |
Collapse
|
10
|
Alves SM, Freitas RS, do Val DR, Vieira LV, de Assis EL, Gomes FIF, Gadelha CADA, Gadelha TS, de Lacerda JTJG, Clemente-Napimoga JT, Pinto VDPT, Cristino Filho G, Bezerra MM, Chaves HV. The efficacy of a lectin from Abelmoschus Esculentus depends on central opioid receptor activation to reduce temporomandibular joint hypernociception in rats. Biomed Pharmacother 2018; 101:478-484. [DOI: 10.1016/j.biopha.2018.02.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/21/2018] [Accepted: 02/23/2018] [Indexed: 12/28/2022] Open
|
11
|
Araújo IWF, Chaves HV, Pachêco JM, Val DR, Vieira LV, Santos R, Freitas RS, Rivanor RL, Monteiro VS, Clemente-Napimoga JT, Bezerra MM, Benevides NMB. Role of central opioid on the antinociceptive effect of sulfated polysaccharide from the red seaweed Solieria filiformis in induced temporomandibular joint pain. Int Immunopharmacol 2017; 44:160-167. [DOI: 10.1016/j.intimp.2017.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 12/15/2016] [Accepted: 01/04/2017] [Indexed: 01/31/2023]
|
12
|
Auh QS, Chun YH, Melemedjian OK, Zhang Y, Ro JY. Peripheral interactions between cannabinoid and opioid receptor agonists in a model of inflammatory mechanical hyperalgesia. Brain Res Bull 2016; 125:211-7. [PMID: 27450703 DOI: 10.1016/j.brainresbull.2016.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/18/2016] [Accepted: 07/19/2016] [Indexed: 01/28/2023]
Abstract
Activation of opioid and cannabinoid receptors expressed in nociceptors induces effective antihyperalgesia. In this study, we examined whether combinations of opioid and cannabinoid receptor agonists directed at the injured site would enhance therapeutic effectiveness. Behavioral pharmacology experiments were performed to compare the effects of DAMGO, a selective agonist for μ-opioid receptor (MOR), ACPA, a specific agonist for CB1, and combinations of DAMGO and ACPA in attenuating complete Freund's adjuvant (CFA)-induced mechanical hyperalgesia in the rat hindpaw. DAMGO (1μg-1mg) or ACPA (1μg-2mg) was administered into the inflamed paw when mechanical hyperalgesia was fully developed. When administered individually, DAMGO and ACPA dose-dependently reversed the mechanical hyperalgesia. DAMGO displayed a lower ED50 value (57.4±2.49μg) than ACPA (111.6±2.18μg), but ACPA produced longer lasting antihyperalgesic effects. Combinations of DAMGO and ACPA also dose-dependently attenuated mechanical hyperalgesia, but the antihyperalgesic effects were partial and transient even at high doses. Using isobolographic analysis, we determined that combined treatment with DAMGO and ACPA produced antagonistic effects with the observed ED50 of 128.4±2.28μg. Our findings showed that MOR and CB1 agonists directed at the inflamed site effectively attenuate mechanical hyperalgesia when administered individually, but exert opposing effects when administered together. The antagonistic interactions between the two classes of drugs at the inflamed site suggest distinct mechanisms unique to peripheral nociceptors or inflamed tissue, and therefore require further studies to investigate whether the therapeutic utility of the combined drug treatments in chronic pain conditions can be optimized.
Collapse
Affiliation(s)
- Q-Schick Auh
- Kyung Hee University, School of Dentistry, Department of Oral Medicine, 1 Hoegi Dong, Dongdaemun Gu, Seoul, Republic of Korea
| | - Yang Hyun Chun
- Kyung Hee University, School of Dentistry, Department of Oral Medicine, 1 Hoegi Dong, Dongdaemun Gu, Seoul, Republic of Korea
| | - Ohannes K Melemedjian
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St., Baltimore, MD 21201, USA
| | - Youping Zhang
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St., Baltimore, MD 21201, USA
| | - Jin Y Ro
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St., Baltimore, MD 21201, USA; Kyung Hee University, School of Dentistry, Department of Oral Medicine, 1 Hoegi Dong, Dongdaemun Gu, Seoul, Republic of Korea.
| |
Collapse
|
13
|
Lee KS, Zhang Y, Asgar J, Auh QS, Chung MK, Ro JY. Androgen receptor transcriptionally regulates μ-opioid receptor expression in rat trigeminal ganglia. Neuroscience 2016; 331:52-61. [PMID: 27320211 DOI: 10.1016/j.neuroscience.2016.06.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/06/2016] [Accepted: 06/11/2016] [Indexed: 12/27/2022]
Abstract
The involvement of testosterone in pain, inflammation, and analgesia has been reported, but the role of androgen receptor (AR), a steroid receptor for testosterone, is not well understood. We have previously shown that peripheral inflammation upregulates μ-opioid receptor (MOR) in rat trigeminal ganglia (TG) in a testosterone-dependent manner. In this study, we hypothesized that testosterone regulates MOR expression via transcriptional activities of AR in TG. We first examined whether AR is co-expressed with MOR in TG neurons. Our immunohistochemical experiment revealed that AR staining is detected in neurons of all sizes in TG and that a subset of AR is expressed in MOR as well as in TRPV1-positive neurons. We identified the promoter region of the rat MOR gene contains putative AR binding sites. Using chromatin immunoprecipitation assay, we demonstrated that AR directly binds to these sites in TG extracts. We confirmed with luciferase reporter assay that AR activated the MOR promoter in response to androgens in a human neuroblastoma cell line (5H-5YSY). These data demonstrated that AR functions as a transcriptional regulator of the MOR gene activity. Finally, we showed that flutamide, a specific AR antagonist, prevents complete Freund's adjuvant (CFA)-induced upregulation of MOR mRNA in TG, and that flutamide dose-dependently blocks the efficacy of DAMGO, a specific MOR agonist, on CFA-induced mechanical hypersensitivity. Our results expand the knowledge regarding the role of androgens and their receptor in pain and analgesia and have important clinical implications, particularly for inflammatory pain patients with low or compromised plasma testosterone levels.
Collapse
Affiliation(s)
- Ki Seok Lee
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St., Baltimore, MD 21201, USA
| | - Youping Zhang
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St., Baltimore, MD 21201, USA
| | - Jamila Asgar
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St., Baltimore, MD 21201, USA
| | - Q-Schick Auh
- Kyung Hee University, School of Dentistry, Department of Oral Medicine, 1 Hoegi Dong, Dongdaemun Gu, Seoul, Republic of Korea
| | - Man-Kyo Chung
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St., Baltimore, MD 21201, USA
| | - Jin Y Ro
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St., Baltimore, MD 21201, USA; Kyung Hee University, School of Dentistry, Department of Oral Medicine, 1 Hoegi Dong, Dongdaemun Gu, Seoul, Republic of Korea.
| |
Collapse
|
14
|
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.
Collapse
|
15
|
Lechner J, von Baehr V. Peripheral Neuropathic Facial/Trigeminal Pain and RANTES/CCL5 in Jawbone Cavitation. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2015; 2015:582520. [PMID: 26170877 PMCID: PMC4481083 DOI: 10.1155/2015/582520] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 04/01/2015] [Indexed: 01/05/2023]
Abstract
Introduction. In this study, we elucidate the possible causative role of chronic subclinical inflammation in jawbone of patients with atypical facial pain (AFP) and trigeminal neuralgia (TRN) in the local overexpression of the chemokine regulated on activation and normal T-cell expressed and secreted (RANTES/C-C motif ligand 5 CCL5). Neurons contain opioid receptors that transmit antipain reactions in the peripheral and central nervous system. Proinflammatory chemokines like RANTES/CCL5 desensitize μ-opioid receptors in the periphery sensory neurons and it has been suggested that RANTES modifies the nociceptive reaction. Materials and Methods. In 15 patients with AFP/TRN, we examined fatty degenerated jawbone (FDOJ) samples for the expression of seven cytokines by multiplex analysis and compared these results with healthy jawbones. Results. Each of these medullary jawbone samples exhibited RANTES as the only highly overexpressed cytokine. The FDOJ cohort with AFP/TRN showed a mean 30-fold overexpression of RANTES compared to healthy jawbones. Conclusions. To the best of our knowledge, no other research has identified RANTES overexpression in silent inflamed jawbones as a possible cause for AFP/TRN. Thus, we hypothesize that the surgical clearing of FDOJ might diminish RANTES signaling pathways in neurons and contribute to resolving chronic neurological pain in AFP/TRN patients.
Collapse
Affiliation(s)
- Johann Lechner
- Clinic for Integrative Dentistry, Gruenwalder Strasse 10A, 81547 Munich, Germany
| | - Volker von Baehr
- Medical Diagnostics-MVZ GbR, Nicolaistrasse 22, 12247 Berlin, Germany
| |
Collapse
|
16
|
Bai X, Zhang X, Li Y, Lu L, Li B, He X. Sex differences in peripheral mu-opioid receptor mediated analgesia in rat orofacial persistent pain model. PLoS One 2015; 10:e0122924. [PMID: 25807259 PMCID: PMC4373836 DOI: 10.1371/journal.pone.0122924] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 02/16/2015] [Indexed: 02/01/2023] Open
Abstract
Unilateral ligation of the tendon of anterior superficial part of rat masseter muscle (TASM) leads to long-lasting allodynia. Sex differences in peripheral mu-opioid receptor (MOR)-mediated analgesia under persistent myogenic pain are not well understood. In this study, we examined (1) whether locally applied MOR agonists attenuate persistent pain following TASM ligation in a sex dependent manner, (2) whether there are sex differences of MOR expression changes in rat trigeminal ganglia (TG). The effects of MOR agonist, D-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin acetate salt (DAMGO), were assessed 14 days after TASM ligation in male, female and orchidectomized (GDX) male rats. MOR mRNA and protein levels in TG 14 days following tendon ligation were also determined. The mechanical thresholds of the injured side were significantly decreased in both male and female rats, from 3 days to 28 days after TASM ligation. A10 μg DAMGO significantly attenuated allodynia in male rats. A 10-fold higher dose of DAMGO was required in female and GDX male rats to produce the level of anti- allodynia achieved in male rats. The level of MOR mRNA in TG from male rats was significantly greater 14 days after TASM ligation compared with the sham-operated male rats, but not from female and GDX male rats. After TASM ligation, males had significantly more MOR immunoreactivity in TG compared to sham-operated males. The MOR levels increased to 181.8% of the sham level in male rats receiving tendon injury. But there was no significant change in female rats receiving tendon injury compared to the sham female rats. Taken together, our data suggest that there were sex differences in the effects of peripheral MOR agonists between male and female rats under TASM ligation developing long-lasting pain condition, which is partly mediated by sex differences in the changes of MOR expressions and testosterone is an important factor in the regulation of MOR.
Collapse
MESH Headings
- Analgesics, Opioid/pharmacology
- Analgesics, Opioid/therapeutic use
- Animals
- Behavior, Animal/drug effects
- Disease Models, Animal
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/therapeutic use
- Facial Pain/drug therapy
- Facial Pain/etiology
- Facial Pain/veterinary
- Female
- Hyperalgesia/drug therapy
- Hyperalgesia/etiology
- Hyperalgesia/pathology
- Immunohistochemistry
- Male
- Orchiectomy
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Real-Time Polymerase Chain Reaction
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Sex Characteristics
- Tendon Injuries/complications
- Tendon Injuries/pathology
- Trigeminal Ganglion/metabolism
- Trigeminal Ganglion/pathology
Collapse
Affiliation(s)
- Xiaofeng Bai
- Associate Professor, Department of Oral and Maxillofacial Surgery, School & Hospital of Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. of China, 110002
- * E-mail: (XZ); (XB)
| | - Xia Zhang
- Associate Professor, Department of Anesthesiology, School & Hospital of Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. of China, 110002
- * E-mail: (XZ); (XB)
| | - Yanshu Li
- Assistant Professor, Department of Cell Biology, China Medical University, 92 Bei'er Road, Shenyang, P. R. of China, 110001
| | - Li Lu
- Professor, Department of Oral and Maxillofacial Surgery, School & Hospital of Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. of China, 110002
| | - Bo Li
- Associate Professor, Department of Oral Anatomy and Physiology, School of Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. of China, 110002
| | - Xiaofan He
- Assistant Professor, Department of Anesthesiology, School & Hospital of Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. of China, 110002
| |
Collapse
|
17
|
Kramer PR, Umorin M, Bellinger LL. Attenuation of myogenic orofacial nociception and mechanical hypersensitivity by viral mediated enkephalin overproduction in male and female rats. BMC Neurol 2015; 15:34. [PMID: 25885338 PMCID: PMC4369359 DOI: 10.1186/s12883-015-0285-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/25/2015] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Clinical studies have tested the use of an engineered herpes virus to treat pain. We hypothesized that subcutaneous injections of an engineered herpes virus that expresses enkephalin would attenuate orofacial nociception and hypersensitivity in male and female rats by a central mechanism. METHODS Herpes virus was injected subcutaneously around the mouth of male and female rats seventy-two hours before ligatures were placed on the masseter tendon, control treatment groups received either no virus or no ligature. Enkephalin expression was measured and von Frey filament testing and meal duration were utilized to measure mechanical hypersensitivity and the nociceptive response, respectively. Naloxone or naloxone methiodide was administered to rats injected with the enkephalin expressing virus to test if enkephalin was acting peripherally or centrally. RESULTS Ligature significantly lengthened meal duration and reduced the threshold to von Frey filaments for 18 days. Infection with the enkephalin transgene significantly decreased this response for at least 11 days but only in male rats. Virus injection significantly increased expression of enkephalin in the mental nerve that innervates the mouth region, the trigeminal ganglia and the trigeminal nucleus caudalis but no increase was observed in the masseter nerve after virus injection. Naloxone but not naloxone methiodide reversed the response to the enkephaline expressing virus. CONCLUSIONS The data suggests that sex should be a considered when using this virus and that viral transfection of the mental nerve with an enkephalin transgene can reduce nociception and hypersensitivity through a central mechanism.
Collapse
Affiliation(s)
- Phillip R Kramer
- Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Avenue, Dallas, TX, 75246, USA.
| | - Mikhail Umorin
- Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Avenue, Dallas, TX, 75246, USA.
| | - Larry L Bellinger
- Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Avenue, Dallas, TX, 75246, USA.
| |
Collapse
|
18
|
Zambelli VO, Fernandes ACDO, Gutierrez VP, Ferreira JCB, Parada CA, Mochly-Rosen D, Cury Y. Peripheral sensitization increases opioid receptor expression and activation by crotalphine in rats. PLoS One 2014; 9:e90576. [PMID: 24594607 PMCID: PMC3942445 DOI: 10.1371/journal.pone.0090576] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 02/04/2014] [Indexed: 11/19/2022] Open
Abstract
Inflammation enhances the peripheral analgesic efficacy of opioid drugs, but the mechanisms involved in this phenomenon have not been fully elucidated. Crotalphine (CRP), a peptide that was first isolated from South American rattlesnake C.d. terrificus venom, induces a potent and long-lasting anti-nociceptive effect that is mediated by the activation of peripheral opioid receptors. Because the high efficacy of CRP is only observed in the presence of inflammation, we aimed to elucidate the mechanisms involved in the CRP anti-nociceptive effect induced by inflammation. Using real-time RT-PCR, western blot analysis and ELISA assays, we demonstrate that the intraplantar injection of prostaglandin E2 (PGE2) increases the mRNA and protein levels of the µ- and κ-opioid receptors in the dorsal root ganglia (DRG) and paw tissue of rats within 3 h of the injection. Using conformation state-sensitive antibodies that recognize activated opioid receptors, we show that PGE2, alone does not increase the activation of these opioid receptors but that in the presence of PGE2, the activation of specific opioid receptors by CRP and selective µ- and κ-opioid receptor agonists (positive controls) increases. Furthermore, PGE2 down-regulated the expression and activation of the δ-opioid receptor. CRP increased the level of activated mitogen-activated protein kinases in cultured DRG neurons, and this increase was dependent on the activation of protein kinase Cζ. This CRP effect was much more prominent when the cells were pretreated with PGE2. These results indicate that the expression and activation of peripheral opioid receptors by opioid-like drugs can be up- or down-regulated in the presence of an acute injury and that acute tissue injury enhances the efficacy of peripheral opioids.
Collapse
MESH Headings
- Analgesics, Opioid/isolation & purification
- Analgesics, Opioid/pharmacology
- Analgesics, Opioid/therapeutic use
- Animals
- Crotalus/metabolism
- Dinoprostone
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/immunology
- Ganglia, Spinal/metabolism
- Gene Expression Regulation/drug effects
- Hyperalgesia/chemically induced
- Hyperalgesia/drug therapy
- Hyperalgesia/genetics
- Hyperalgesia/immunology
- Male
- Peptides/isolation & purification
- Peptides/pharmacology
- Peptides/therapeutic use
- Rats
- Rats, Wistar
- Receptors, Opioid/agonists
- Receptors, Opioid/genetics
- Receptors, Opioid/immunology
Collapse
Affiliation(s)
| | | | | | | | - Carlos Amilcar Parada
- Departamento de Fisiologia e Biofísica, Instituto de Biociências (UNICAMP) Rua Monteiro Lobato, Cidade Universitária, Campinas, SP, Brazil
| | - Daria Mochly-Rosen
- Department of Chemical and Systems Biology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Yara Cury
- Laboratório Especial de Dor e Sinalização, Instituto Butantan, São Paulo, SP, Brazil
- * E-mail:
| |
Collapse
|
19
|
Zhang X, Zhang Y, Asgar J, Niu KY, Lee J, Lee KS, Schneider M, Ro JY. Sex differences in μ-opioid receptor expression in trigeminal ganglia under a myositis condition in rats. Eur J Pain 2014; 18:151-61. [PMID: 23801566 PMCID: PMC3916151 DOI: 10.1002/j.1532-2149.2013.00352.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND Peripheral opioid receptor expression is up-regulated under inflammatory conditions, which leads to the increased efficacy of peripherally administered opioids. Sex differences in the effects of inflammation, cytokines and gonadal hormones on μ-opioid receptor (MOR) expression in trigeminal ganglia (TG) are not well understood. METHODS MOR mRNA and protein levels in TG from male and female Sprague Dawley rats following complete Freund's adjuvant (CFA)-induced muscle inflammation were assessed. Cytokine-induced changes in MOR mRNA expression from TG cultures prepared from intact and gonadectomized male and female, and gonadectomized male rats with testosterone replacement were examined. Behavioural experiments were then performed to examine the efficacy of a peripherally administered MOR agonist in male, female and gonadectomized male rats under a myositis condition. RESULTS CFA and cytokine treatments induced significant up-regulation of MOR expression in TG from male, but not from female, rats. The cytokine-induced up-regulation of MOR mRNA expression was prevented in TG from orchidectomized (GDX) male rats, which was restored with testosterone replacement. Peripherally administered DAMGO, a specific MOR agonist, significantly attenuated CFA-induced masseter mechanical hypersensitivity only in intact male rats. CONCLUSIONS Collectively, these data indicate that testosterone plays a key role in the regulation of MOR in TG under inflammatory conditions, and that sex differences in the anti-hyperalgesic effects of peripherally administered opioids are, in part, mediated by peripheral opioid receptor expression levels.
Collapse
Affiliation(s)
- X Zhang
- China Medical University, Hospital of Stomatology, The First Affiliated Hospital, Department of Anesthesiology, Shenyang, 110002, China
| | - Y Zhang
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St, Baltimore, MD 21201
| | - J Asgar
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St, Baltimore, MD 21201
| | - KY Niu
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St, Baltimore, MD 21201
| | - J Lee
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St, Baltimore, MD 21201
| | - KS Lee
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St, Baltimore, MD 21201
| | - M Schneider
- University of Maryland School of Dentistry, Department of Orthodontics, 650 W. Baltimore St, Baltimore, MD 21201
| | - JY Ro
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, 650 W. Baltimore St, Baltimore, MD 21201
| |
Collapse
|
20
|
Lee KS, Asgar J, Zhang Y, Chung MK, Ro JY. The role of androgen receptor in transcriptional modulation of cannabinoid receptor type 1 gene in rat trigeminal ganglia. Neuroscience 2013; 254:395-403. [PMID: 24055403 DOI: 10.1016/j.neuroscience.2013.09.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 12/31/2022]
Abstract
We have previously shown that anti-hyperalgesic effects of cannabinoid agonists under inflammatory condition are much greater in male than female, and that inflammatory cytokines upregulate cannabinoid receptor type 1 (CB1) expression in male, but not female, trigeminal ganglia (TG) in a testosterone-dependent manner. In this study, we investigated the mechanisms underlying the testosterone-mediated regulation of peripheral CB1 expression. We hypothesized that testosterone upregulates CB1 through transcriptional modulation by androgen receptor (AR). Interleukin-1 beta (IL-1β), a pro-inflammatory cytokine, upregulated CB1 mRNA expression in TG of male rats. The cytokine-induced upregulation was prevented by the pretreatment with flutamide, a specific antagonist for AR, but not by ICI 182,780, a specific antagonist for estrogen receptor, suggesting that the effects of testosterone are not mediated by estradiol, a testosterone metabolite. The expression levels of AR and IL-1β receptors were comparable between male and female TG, suggesting that the male specific IL-1β effects on CB1 upregulation occurs downstream to these receptors. The chromatin immunoprecipitation assay showed AR binding to the CB1 promoter in the rat TG. Furthermore, luciferase reporter assay revealed that AR activated the CB1 gene in response to testosterone or dihydrotestosterone treatment. These experiments provided compelling evidence that testosterone regulates CB1 gene transcription in TG through AR following cytokine stimulation. These results should provide mechanistic bases for understanding cytokine-hormone-neuron interactions in peripheral cannabinoid systems, and have important clinical implications for pain patients in whom testosterone level is naturally low, gradually declining or pharmacologically compromised.
Collapse
Affiliation(s)
- K S Lee
- University of Maryland Dental School, Department of Neural and Pain Sciences, Program in Neuroscience, Baltimore, MD 21201, USA
| | | | | | | | | |
Collapse
|
21
|
Ramesh G, MacLean AG, Philipp MT. Cytokines and chemokines at the crossroads of neuroinflammation, neurodegeneration, and neuropathic pain. Mediators Inflamm 2013; 2013:480739. [PMID: 23997430 PMCID: PMC3753746 DOI: 10.1155/2013/480739] [Citation(s) in RCA: 388] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/11/2013] [Accepted: 07/12/2013] [Indexed: 01/18/2023] Open
Abstract
Cytokines and chemokines are proteins that coordinate the immune response throughout the body. The dysregulation of cytokines and chemokines is a central feature in the development of neuroinflammation, neurodegeneration, and demyelination both in the central and peripheral nervous systems and in conditions of neuropathic pain. Pathological states within the nervous system can lead to activation of microglia. The latter may mediate neuronal and glial cell injury and death through production of proinflammatory factors such as cytokines and chemokines. These then help to mobilize the adaptive immune response. Although inflammation may induce beneficial effects such as pathogen clearance and phagocytosis of apoptotic cells, uncontrolled inflammation can result in detrimental outcomes via the production of neurotoxic factors that exacerbate neurodegenerative pathology. In states of prolonged inflammation, continual activation and recruitment of effector cells can establish a feedback loop that perpetuates inflammation and ultimately results in neuronal injury. A critical balance between repair and proinflammatory factors determines the outcome of a neurodegenerative process. This review will focus on how cytokines and chemokines affect neuroinflammation and disease pathogenesis in bacterial meningitis and brain abscesses, Lyme neuroborreliosis, human immunodeficiency virus encephalitis, and neuropathic pain.
Collapse
Affiliation(s)
- Geeta Ramesh
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Tulane University, 18703 Three Rivers Road, Covington, LA 70433, USA.
| | | | | |
Collapse
|
22
|
Chung MK, Cho YS, Bae YC, Lee J, Zhang X, Ro JY. Peripheral G protein-coupled inwardly rectifying potassium channels are involved in δ-opioid receptor-mediated anti-hyperalgesia in rat masseter muscle. Eur J Pain 2013; 18:29-38. [PMID: 23740773 DOI: 10.1002/j.1532-2149.2013.00343.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2013] [Indexed: 11/06/2022]
Abstract
BACKGROUND Although the efficacy of peripherally administered opioid has been demonstrated in preclinical and clinical studies, the underlying mechanisms of its anti-hyperalgesic effects are poorly understood. G protein-coupled inwardly rectifying potassium (GIRK) channels are linked to opioid receptors in the brain. However, the role of peripheral GIRK channels in analgesia induced by peripherally administered opioid, especially in trigeminal system, is not clear. METHODS Expression of GIRK subunits in rat trigeminal ganglia (TG) was examined with reverse transcription-polymerase chain reaction, Western blot and immunohistochemistry. Chemical profiles of GIRK-expressing neurons in TG were further characterized. Behavioural and Fos experiments were performed to examine the functional involvement of GIRK channels in δ-opioid receptor (DOR)-mediated anti-hyperalgesia under an acute myositis condition. RESULTS TG expressed mRNA and proteins for GIRK1 and GIRK2 subunits. Majority of GIRK1- and GIRK2-expressing neurons were non-peptidergic afferents. Inhibition of peripheral GIRK using Tertiapin-Q (TPQ) attenuated antinociceptive effects of peripherally administered DOR agonist, [D-Pen(2), D-Pen(6) ]-enkephalin (DPDPE), on mechanical hypersensitivity in masseter muscle. Furthermore, TPQ attenuated the suppressive effects of peripheral DPDPE on neuronal activation in the subnucleus caudalis of the trigeminal nucleus (Vc) following masseteric injection of capsaicin. CONCLUSIONS Our data indicate that peripheral DOR agonist-induced suppression of mechanical hypersensitivity in the masseter muscle involves the activity of peripheral GIRK channels. These results could provide a rationale for developing a novel therapeutic approach using peripheral GIRK channel openers to mimic or supplement the effects of peripheral opioid agonist.
Collapse
Affiliation(s)
- M-K Chung
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, USA
| | | | | | | | | | | |
Collapse
|
23
|
Miranda HF, Noriega V, Zepeda RJ, Sierralta F, Prieto JC. Systemic synergism between codeine and morphine in three pain models in mice. Pharmacol Rep 2013; 65:80-8. [DOI: 10.1016/s1734-1140(13)70966-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 09/04/2012] [Indexed: 01/08/2023]
|
24
|
Saloman JL, Niu KY, Ro JY. Activation of peripheral delta-opioid receptors leads to anti-hyperalgesic responses in the masseter muscle of male and female rats. Neuroscience 2011; 190:379-85. [PMID: 21664434 DOI: 10.1016/j.neuroscience.2011.05.062] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 05/23/2011] [Accepted: 05/25/2011] [Indexed: 11/18/2022]
Abstract
In this project, we examined peripheral δ-opioid receptor (DOR)-mediated anti-hyperalgesic responses in the context of an acute orofacial muscle pain condition in both male and female rats. We also investigated whether the ATP-sensitive K+ channel (KATP), a downstream target of OR signaling, contributes to DOR-mediated anti-hyperalgesic responses. Local pretreatment of the masseter with a DOR agonist, [D-Pen², D-Pen⁶]-enkephalin (DPDPE), dose-dependently attenuated capsaicin-induced mechanical hypersensitivity in both male and female rats. However, there were sex differences in the potency of local DPDPE in that a 10-fold higher dose of DPDPE was required in female rats to produce the level of anti-hyperalgesia achieved in male rats. The sex differences in the DPDPE effect may not be fully explained by DOR expression level since there was no significant sex difference in DOR mRNA levels in trigeminal ganglia (TG). Finally, pretreatment of the masseter with the KATP antagonist, glibenclamide, significantly blocked the effects of DPDPE in male rats suggesting that the peripheral DOR effect is mediated by the KATP. These studies revealed novel information about sex differences with regards to peripherally localized DOR-mediated anti-hyperalgesia under an orofacial muscle pain condition.
Collapse
Affiliation(s)
- J L Saloman
- Program in Neuroscience, Department of Neural and Pain Sciences, University of Maryland Baltimore School of Dentistry, 650 W. Baltimore Street, Baltimore, MD 21201, USA
| | | | | |
Collapse
|
25
|
McDougall JJ. Peripheral analgesia: Hitting pain where it hurts. Biochim Biophys Acta Mol Basis Dis 2011; 1812:459-67. [DOI: 10.1016/j.bbadis.2010.12.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 12/09/2010] [Accepted: 12/15/2010] [Indexed: 10/18/2022]
|
26
|
Effect of tooth pulp and periaqueductal central gray stimulation on the expression of genes encoding the selected neuropeptides and opioid receptors in the mesencephalon, hypothalamus and thalamus in rats. Brain Res 2011; 1382:19-28. [DOI: 10.1016/j.brainres.2011.01.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 12/20/2010] [Accepted: 01/09/2011] [Indexed: 11/22/2022]
|
27
|
Niu KY, Ro JY. Changes in intramuscular cytokine levels during masseter inflammation in male and female rats. Neurosci Lett 2010; 487:223-7. [PMID: 20969918 DOI: 10.1016/j.neulet.2010.10.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 10/02/2010] [Accepted: 10/09/2010] [Indexed: 02/07/2023]
Abstract
The present study was conducted to examine cytokine profiles in the masseter muscle before and after complete Freund's adjuvant (CFA)-induced inflammation and possible sex differences in the cytokine levels. Age matched male and female Sprague Dawley rats were injected with CFA in the mid-region of the masseter muscle. Muscle tissue surrounding the injection site was extracted 6h, 1, 3 and 7 days after the injection to measure TNF-α, IL-1β, IL-6 and IL-4 levels with Luminex multi-analyte profiling (xMAP) technology. The cytokine levels were compared to those obtained from naïve rats. CFA injection into the masseter muscle led to a significant time effect in the level of TNF-α compared to that of naïve rats. The pattern of changes in TNF-α level after CFA injection was significantly different between the male and female rats owing to the differences in basal levels. CFA injection induced significant time-dependent increases in the levels of IL-1β and IL-6 in the masseter muscle in both male and female rats. The level of IL-4 was slightly, but significantly, reduced in both sexes at 6h and 3 days after CFA-induced inflammation. No significant sex differences were observed in the levels of IL-1β, IL-6 or IL-4. The results provided novel information about distinct cytokine profiles during CFA-induced muscle inflammation, and the basis for further pursuing contributions of each cytokine in pain processing and analgesic responses in both sexes.
Collapse
Affiliation(s)
- Katelyn Y Niu
- University of Maryland Baltimore, Department of Neural and Pain Sciences, Baltimore, MD 21201, USA
| | | |
Collapse
|
28
|
Sánchez EM, Bagües A, Martín MI. Contributions of peripheral and central opioid receptors to antinociception in rat muscle pain models. Pharmacol Biochem Behav 2010; 96:488-95. [PMID: 20637793 DOI: 10.1016/j.pbb.2010.07.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 06/17/2010] [Accepted: 07/09/2010] [Indexed: 11/18/2022]
Abstract
Administration of hypertonic saline (HS) is an accepted model to study muscular pain. HS-induced nociceptive responses were tested in masseter, already described, and in two new pain models of spinally innervated muscles (gastrocnemius and triceps) developed in rats at our laboratory. HS administration in the masseter induced vigorous hindpaw shaking and in the gastrocnemius or triceps, paw withdrawal or flexing. Participation of the central and peripheral opioid receptors in HS-induced pain is compared in these muscles: masseter, innervated by trigeminal nerve, and gastrocnemius and triceps by spinal nerves. Morphine and loperamide were used to reveal peripheral and central components of opioid analgesia. Both agonists reduced HS-induced nociceptive behaviours in the masseter and were antagonised by the opioid antagonist naloxone and by naloxone methiodide, an opioid receptor antagonist that poorly penetrates the blood-brain barrier. Unexpectedly, in the gastrocnemius and triceps, morphine, but not loperamide, decreased the nociceptive behaviour and this effect was only reversed by naloxone. So, peripheral opioid receptors seem to participate in HS-induced masseter pain, whereas only central opioid receptors reduced the nociception in gastrocnemius and triceps. Our results suggest that the use of peripheral opioids can be more advantageous than central opioids for treatment of orofacial muscular pain.
Collapse
Affiliation(s)
- Eva Ma Sánchez
- Departamento de Farmacología y Nutrición, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Madrid, Spain.
| | | | | |
Collapse
|
29
|
Tsuchimochi H, McCord JL, Kaufman MP. Peripheral mu-opioid receptors attenuate the augmented exercise pressor reflex in rats with chronic femoral artery occlusion. Am J Physiol Heart Circ Physiol 2010; 299:H557-65. [PMID: 20543079 DOI: 10.1152/ajpheart.00387.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recently, opioid receptors have been shown to be expressed on group III and IV afferents, which comprise the sensory arm of the exercise pressor reflex. Although the stimulation of opioid receptors in the central nervous system has been shown to attenuate the exercise pressor reflex, the effect on the reflex of their stimulation in the periphery is unknown. We therefore tested the hypothesis that the activation of peripheral mu-opioid receptors attenuates the exercise pressor reflex. The pressor responses to static contraction were compared before and after the injection of the mu-opioid receptor agonist [d-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin (DAMGO; 1 microg) into the abdominal aorta of decerebrated rats in which one femoral artery had been occluded 72 h previously (n = 10) and in control rats whose femoral arteries were freely perfused (n = 8). DAMGO attenuated the peak pressor response to contraction in rats whose femoral arteries had been occluded (before: increase of 34 + or - 3 mmHg and after: increase of 22 + or - 2 mmHg, P = 0.008); the inhibitory effect of DAMGO was prevented by the injection of naloxone (100 microg) into the abdominal aorta (before: increase of 29 + or - 5 mmHg and after: increase of 29 + or - 5 mmHg, P = 0.646, n = 7). An intravenous injection of DAMGO (1 microg, n = 6) had no effect on the peak pressor response to contraction in both groups of rats. DAMGO had no effect on the peak pressor response to contraction in rats whose femoral arteries were freely perfused (before: Delta 23 + or - 4 mmHg, after: Delta 23 + or - 3 mmHg, n = 6) but appeared to have a small effect on topography of the response. DAMGO had no effect on the peak pressor response to tendon stretch in both groups of rats (both P > 0.05). We conclude that the stimulation of peripheral mu-opioid receptors attenuates the exercise pressor reflex in rats whose femoral arteries have been ligated for 72 h.
Collapse
Affiliation(s)
- Hirotsugu Tsuchimochi
- Penn State Heart and Vascular Institute, 500 University Dr., Mail Code H047, Hershey Medical Center, Hershey, PA 17033, USA.
| | | | | |
Collapse
|
30
|
Tsuchimochi H, McCord JL, Kaufman MP. Peripheral mu-opioid receptors attenuate the augmented exercise pressor reflex in rats with chronic femoral artery occlusion. Am J Physiol Heart Circ Physiol 2010; 299:H106-13. [PMID: 20543079 DOI: 10.1152/ajpheart.00141.2010] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recently, opioid receptors have been shown to be expressed on group III and IV afferents, which comprise the sensory arm of the exercise pressor reflex. Although the stimulation of opioid receptors in the central nervous system has been shown to attenuate the exercise pressor reflex, the effect on the reflex of their stimulation in the periphery is unknown. We therefore tested the hypothesis that the activation of peripheral mu-opioid receptors attenuates the exercise pressor reflex. The pressor responses to static contraction were compared before and after the injection of the mu-opioid receptor agonist [d-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin (DAMGO; 1 microg) into the abdominal aorta of decerebrated rats in which one femoral artery had been occluded 72 h previously (n = 10) and in control rats whose femoral arteries were freely perfused (n = 8). DAMGO attenuated the peak pressor response to contraction in rats whose femoral arteries had been occluded (before: increase of 34 + or - 3 mmHg and after: increase of 22 + or - 2 mmHg, P = 0.008); the inhibitory effect of DAMGO was prevented by the injection of naloxone (100 microg) into the abdominal aorta (before: increase of 29 + or - 5 mmHg and after: increase of 29 + or - 5 mmHg, P = 0.646, n = 7). An intravenous injection of DAMGO (1 microg, n = 6) had no effect on the peak pressor response to contraction in both groups of rats. DAMGO had no effect on the peak pressor response to contraction in rats whose femoral arteries were freely perfused (before: Delta 23 + or - 4 mmHg, after: Delta 23 + or - 3 mmHg, n = 6) but appeared to have a small effect on topography of the response. DAMGO had no effect on the peak pressor response to tendon stretch in both groups of rats (both P > 0.05). We conclude that the stimulation of peripheral mu-opioid receptors attenuates the exercise pressor reflex in rats whose femoral arteries have been ligated for 72 h.
Collapse
Affiliation(s)
- Hirotsugu Tsuchimochi
- Penn State Heart and Vascular Institute, 500 University Dr., Mail Code H047, Hershey Medical Center, Hershey, PA 17033, USA.
| | | | | |
Collapse
|
31
|
Abstract
This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, 65-30 Kissena Blvd.,Flushing, NY 11367, United States.
| |
Collapse
|
32
|
Bai G, Ambalavanar R, Wei D, Dessem D. Downregulation of selective microRNAs in trigeminal ganglion neurons following inflammatory muscle pain. Mol Pain 2007; 3:15. [PMID: 17559665 PMCID: PMC1896151 DOI: 10.1186/1744-8069-3-15] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Accepted: 06/08/2007] [Indexed: 01/15/2023] Open
Abstract
Active regulation of gene expression in the nervous system plays an important role in the development and/or maintenance of inflammatory pain. MicroRNA (miRNA) negatively regulates gene expression via posttranscriptional or transcriptional inhibition of specific genes. To explore the possible involvement of miRNA in gene regulation during inflammatory pain, we injected complete Freund's adjuvant (CFA) unilaterally into the rat masseter muscle and quantified changes in neuron-specific mature miRNAs in the trigeminal ganglion (TG). Real-time reverse-transcription polymerase chain reaction revealed significant, but differential, downregulation of mature miR-10a, -29a, -98, -99a, -124a, -134, and -183 in the ipsilateral mandibular division (V3) of the TG within 4 hr after CFA. In contrast, levels of tested miRNAs did not change significantly in the contralateral V3 or the ipsilateral ophthalmic and maxillary divisions of the TG from inflamed rats, nor in the ipsilateral V3 of saline-injected animals. The downregulated miRNAs recovered differentially to a level equal to or higher than that in naive animals. Full recovery time varied with miRNA species but was at least 4 days. Expression and downregulation of some miRNAs were further confirmed by in situ hybridization of TG neurons that innervate the inflamed muscle. Although neurons of all sizes expressed these miRNAs, their signals varied between neurons. Our results indicate that miRNA species specific to neurons are quickly regulated following inflammatory muscle pain.
Collapse
Affiliation(s)
- Guang Bai
- Department of Biomedical Sciences, Program in Neuroscience, University Maryland Dental School, Baltimore, MD, USA
| | - Rajini Ambalavanar
- Department of Biomedical Sciences, Program in Neuroscience, University Maryland Dental School, Baltimore, MD, USA
| | - Dong Wei
- Department of Biomedical Sciences, Program in Neuroscience, University Maryland Dental School, Baltimore, MD, USA
| | - Dean Dessem
- Department of Biomedical Sciences, Program in Neuroscience, University Maryland Dental School, Baltimore, MD, USA
| |
Collapse
|