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Kudsi SQ, Viero FT, Pereira LG, Trevisan G. Involvement of the Transient Receptor Channels in Preclinical Models of Musculoskeletal Pain. Curr Neuropharmacol 2024; 22:72-87. [PMID: 37694792 DOI: 10.2174/1570159x21666230908094159] [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: 04/10/2023] [Revised: 08/14/2023] [Accepted: 08/16/2023] [Indexed: 09/12/2023] Open
Abstract
BACKGROUND Musculoskeletal pain is a condition that affects bones, muscles, and tendons and is present in various diseases and/or clinical conditions. This type of pain represents a growing problem with enormous socioeconomic impacts, highlighting the importance of developing treatments tailored to the patient's needs. TRP is a large family of non-selective cation channels involved in pain perception. Vanilloid (TRPV1 and TRPV4), ankyrin (TRPA1), and melastatin (TRPM8) are involved in physiological functions, including nociception, mediation of neuropeptide release, heat/cold sensing, and mechanical sensation. OBJECTIVE In this context, we provide an updated view of the most studied preclinical models of muscle hyperalgesia and the role of transient receptor potential (TRP) in these models. METHODS This review describes preclinical models of muscle hyperalgesia induced by intramuscular administration of algogenic substances and/or induction of muscle damage by physical exercise in the masseter, gastrocnemius, and tibial muscles. RESULTS The participation of TRPV1, TRPA1, and TRPV4 in different models of musculoskeletal pain was evaluated using pharmacological and genetic tools. All the studies detected the antinociceptive effect of respective antagonists or reduced nociception in knockout mice. CONCLUSION Hence, TRPV1, TRPV4, and TRPA1 blockers could potentially be utilized in the future for inducing analgesia in muscle hypersensitivity pathologies.
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Affiliation(s)
- Sabrina Qader Kudsi
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria (UFSM), Avenida Roraima, 97105-900 Santa Maria (RS), Brazil
| | - Fernanda Tibolla Viero
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria (UFSM), Avenida Roraima, 97105-900 Santa Maria (RS), Brazil
| | - Leonardo Gomes Pereira
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria (UFSM), Avenida Roraima, 97105-900 Santa Maria (RS), Brazil
| | - Gabriela Trevisan
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria (UFSM), Avenida Roraima, 97105-900 Santa Maria (RS), Brazil
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2
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Liao J, Wu Q, Qian C, Zhao N, Zhao Z, Lu K, Zhang S, Dong Q, Chen L, Li Q, Du Y. TRPV4 blockade suppresses atrial fibrillation in sterile pericarditis rats. JCI Insight 2020; 5:137528. [PMID: 33119551 PMCID: PMC7714415 DOI: 10.1172/jci.insight.137528] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 10/22/2020] [Indexed: 12/15/2022] Open
Abstract
Atrial fibrillation (AF) commonly occurs after surgery and is associated with atrial remodeling. TRPV4 is functionally expressed in the heart, and its activation affects cardiac structure and functions. We hypothesized that TRPV4 blockade alleviates atrial remodeling and reduces AF induction in sterile pericarditis (SP) rats. TRPV4 antagonist GSK2193874 or vehicle was orally administered 1 day before pericardiotomy. AF susceptibility and atrial function were assessed using in vivo electrophysiology, ex vivo optical mapping, patch clamp, and molecular biology on day 3 after surgery. TRPV4 expression increased in the atria of SP rats and patients with AF. GSK2193874 significantly reduced AF vulnerability in vivo and the frequency of atrial ectopy and AF with a reentrant pattern ex vivo. Mechanistically, GSK2193874 reversed the abnormal action potential duration (APD) prolongation in atrial myocytes through the regulation of voltage-gated K+ currents (IK); reduced the activation of atrial fibroblasts by inhibiting P38, AKT, and STAT3 pathways; and alleviated the infiltration of immune cells. Our results reveal that TRPV4 blockade prevented abnormal changes in atrial myocyte electrophysiology and ameliorated atrial fibrosis and inflammation in SP rats; therefore, it might be a promising strategy to treat AF, particularly postoperative AF. TRPV4 blockade prevents abnormal changes in atrial myocyte electrophysiology and ameliorated atrial fibrosis in rats and might be a promising strategy to treat atrial fibrillation.
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Affiliation(s)
- Jie Liao
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qiongfeng Wu
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Cheng Qian
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ning Zhao
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhaoyang Zhao
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kai Lu
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shaoshao Zhang
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qian Dong
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Chen
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Qince Li
- Harbin Institute of Technology, Nangang District, Harbin, China
| | - Yimei Du
- Department of Cardiology.,Research Center of Ion Channelopathy.,Institute of Cardiology, and.,Key Lab for Biological Targeted Therapy of Education Ministry and Hubei Province, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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3
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Huang X, Hu Y, Zhao L, Gu B, Zhu R, Li Y, Yang Y, Han T, Yu J, Mu L, Han P, Li C, Zhang W, Hu Y. TRPV4 plays an important role in rat prefrontal cortex changes induced by acute hypoxic exercise. Saudi J Biol Sci 2019; 26:1194-1206. [PMID: 31516349 PMCID: PMC6734159 DOI: 10.1016/j.sjbs.2019.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/29/2019] [Accepted: 06/02/2019] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE This study aims to investigate the effects of TRPV4 on acute hypoxic exercise-induced central fatigue, in order to explore the mechanism in central for exercise capacity decline of athletes in the early stage of altitude training. METHODS 120 male Wistar rats were randomly divided into 12 groups: 4 normoxia groups (quiet group, 5-level group, 8-level group, exhausted group), 4 groups at simulated 2500 m altitude (grouping as before), 4 groups at simulated 4500 m altitude (grouping as before), 10 in each group. With incremental load movement, materials were drawn corresponding to the load. Intracellular calcium ion concentration was measured by HE staining, enzyme-linked immunosorbent assay, immunohistochemistry, RT-qPCR, Fluo-4/AM and Fura-2/AM fluorescence staining. RESULTS (1) Hypoxic 2-5 groups showed obvious venous congestion, with symptoms similar to normoxia-8 group; Hypoxic 2-8 groups showed meningeal loosening edema, infra-meningeal venous congestion, with symptoms similar to normoxia-exhausted group and hypoxic 1-exhaused group. (2) For 5,6-EET, regardless of normoxic or hypoxic environment, significant or very significant differences existed between each exercise load group (normoxic - 5 level 20.58 ± 0.66 pg/mL, normoxic - 8 level 23.15 ± 0.46 pg/mL, normoxic - exhausted 26.66 ± 0.71 pg/mL; hypoxic1-5 level 21.72 ± 0.43 pg/mL, hypoxic1-8 level 24.73 ± 0.69 pg/mL, hypoxic 1-exhausted 28.68 ± 0.48 pg/mL; hypoxic2-5 level 22.75 ± 0.20 pg/mL, hypoxic2-8 level 25.62 ± 0.39 pg/mL, hypoxic 2-exhausted 31.03 ± 0.41 pg/mL) and quiet group in the same environment(normoxic-quiet 18.12 ± 0.65 pg/mL, hypoxic 1-quiet 19.94 ± 0.43 pg/mL, hypoxic 2-quiet 21.72 ± 0.50 pg/mL). The 5,6-EET level was significantly or extremely significantly increased in hypoxic 1 environment and hypoxic 2 environment compared with normoxic environment under the same load. (3) With the increase of exercise load, expression of TRPV4 in the rat prefrontal cortex was significantly increased; hypoxic exercise groups showed significantly higher TRPV4 expression than the normoxic group. (4) Calcium ion concentration results showed that in the three environments, 8 level group (normoxic-8 190.93 ± 6.11 nmol/L, hypoxic1-8 208.92 ± 6.20 nmol/L, hypoxic2-8 219.13 ± 4.57 nmol/L) showed very significant higher concentration compared to quiet state in the same environment (normoxic-quiet 107.11 ± 0.49 nmol/L, hypoxic 1-quiet 128.48 ± 1.51 nmol/L, hypoxic 2-quiet 171.71 ± 0.84 nmol/L), and the exhausted group in the same environment (normoxic-exhausted 172.51 ± 3.30 nmol/L, hypoxic 1-exhausted 164.54 ± 6.01 nmol/L, hypoxic 2-exhausted 154.52 ± 1.80 nmol/L) had significant lower concentration than 8-level group; hypoxic2-8 had significant higher concentration than normoxic-8. CONCLUSION Acute hypoxic exercise increases the expression of TRPV4 channel in the prefrontal cortex of the brain. For a lower ambient oxygen concentration, expression of TRPV4 channel is higher, suggesting that TRPV4 channel may be one important mechanism involved in calcium overload in acute hypoxic exercise.
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Affiliation(s)
- Xing Huang
- School of Kinesiology and Health, Capital University of Physical
Education and Sports, Beijing 100191, China
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Yanxin Hu
- College of Veterinary Medicine, China Agricultural University, Beijing
100193, China
| | - Li Zhao
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Boya Gu
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Rongxin Zhu
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Yan Li
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Yun Yang
- School of Kinesiology and Health, Capital University of Physical
Education and Sports, Beijing 100191, China
| | - Tianyu Han
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Jiabei Yu
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Lianwei Mu
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Peng Han
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Cui Li
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Weijia Zhang
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
| | - Yang Hu
- School of Sport Science, Beijing Sport University, Beijing 100084,
China
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4
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Hossain MZ, Bakri MM, Yahya F, Ando H, Unno S, Kitagawa J. The Role of Transient Receptor Potential (TRP) Channels in the Transduction of Dental Pain. Int J Mol Sci 2019; 20:ijms20030526. [PMID: 30691193 PMCID: PMC6387147 DOI: 10.3390/ijms20030526] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 12/18/2022] Open
Abstract
Dental pain is a common health problem that negatively impacts the activities of daily living. Dentine hypersensitivity and pulpitis-associated pain are among the most common types of dental pain. Patients with these conditions feel pain upon exposure of the affected tooth to various external stimuli. However, the molecular mechanisms underlying dental pain, especially the transduction of external stimuli to electrical signals in the nerve, remain unclear. Numerous ion channels and receptors localized in the dental primary afferent neurons (DPAs) and odontoblasts have been implicated in the transduction of dental pain, and functional expression of various polymodal transient receptor potential (TRP) channels has been detected in DPAs and odontoblasts. External stimuli-induced dentinal tubular fluid movement can activate TRP channels on DPAs and odontoblasts. The odontoblasts can in turn activate the DPAs by paracrine signaling through ATP and glutamate release. In pulpitis, inflammatory mediators may sensitize the DPAs. They could also induce post-translational modifications of TRP channels, increase trafficking of these channels to nerve terminals, and increase the sensitivity of these channels to stimuli. Additionally, in caries-induced pulpitis, bacterial products can directly activate TRP channels on DPAs. In this review, we provide an overview of the TRP channels expressed in the various tooth structures, and we discuss their involvement in the development of dental pain.
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Affiliation(s)
- Mohammad Zakir Hossain
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Marina Mohd Bakri
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Farhana Yahya
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Hiroshi Ando
- Department of Biology, School of Dentistry, Matsumoto Dental University, 1780 Gobara, Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Shumpei Unno
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Junichi Kitagawa
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
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5
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Moore C, Gupta R, Jordt SE, Chen Y, Liedtke WB. Regulation of Pain and Itch by TRP Channels. Neurosci Bull 2018; 34:120-142. [PMID: 29282613 PMCID: PMC5799130 DOI: 10.1007/s12264-017-0200-8] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/27/2017] [Indexed: 02/07/2023] Open
Abstract
Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular sensors of chemical, thermal, and mechanical noxious stimuli to evoke the pain and itch sensations. Among them are the TRPA1 channel, members of the vanilloid subfamily (TRPV1, TRPV3, and TRPV4), and finally members of the melastatin group (TRPM2, TRPM3, and TRPM8). Given that pain and itch are pro-survival, evolutionarily-honed protective mechanisms, care has to be exercised when developing inhibitory/modulatory compounds targeting specific pain/itch-TRPs so that physiological protective mechanisms are not disabled to a degree that stimulus-mediated injury can occur. Such events have impeded the development of safe and effective TRPV1-modulating compounds and have diverted substantial resources. A beneficial outcome can be readily accomplished via simple dosing strategies, and also by incorporating medicinal chemistry design features during compound design and synthesis. Beyond clinical use, where compounds that target more than one channel might have a place and possibly have advantageous features, highly specific and high-potency compounds will be helpful in mechanistic discovery at the structure-function level.
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Affiliation(s)
- Carlene Moore
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Rupali Gupta
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Sven-Eric Jordt
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Yong Chen
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Wolfgang B Liedtke
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA.
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6
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Hong Z, Tian Y, Qi M, Li Y, Du Y, Chen L, Liu W, Chen L. Transient Receptor Potential Vanilloid 4 Inhibits γ-Aminobutyric Acid-Activated Current in Hippocampal Pyramidal Neurons. Front Mol Neurosci 2016; 9:77. [PMID: 27616980 PMCID: PMC4999446 DOI: 10.3389/fnmol.2016.00077] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/10/2016] [Indexed: 12/26/2022] Open
Abstract
The balance between excitatory and inhibitory neurotransmitter systems is crucial for the modulation of neuronal excitability in the central nervous system (CNS). The activation of transient receptor potential vanilloid 4 (TRPV4) is reported to enhance the response of hippocampal glutamate receptors, but whether the inhibitory neurotransmitter system can be regulated by TRPV4 remains unknown. γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the CNS. Here, we show that application of transient receptor potential vanilloid 4 (TRPV4) synthetic (GSK1016790A or 4α-PDD) or endogenous agonist (5,6-EET) inhibited GABA-activated current (IGABA) in hippocampal CA1 pyramidal neurons, which was blocked by specific antagonists of TRPV4 and of GABAA receptors. GSK1016790A increased the phosphorylated AMP-activated protein kinase (p-AMPK) and decreased the phosphorylated protein kinase B (p-Akt) protein levels, which was attenuated by removing extracellular calcium or by a calcium/calmodulin-dependent protein kinase kinase-β antagonist. GSK1016790A-induced decrease of p-Akt protein level was sensitive to an AMPK antagonist. GSK1016790A-inhibited IGABA was blocked by an AMPK antagonist or a phosphatidyl inositol 3 kinase (PI3K) agonist. GSK1016790A-induced inhibition of IGABA was also significantly attenuated by a protein kinase C (PKC) antagonist but was unaffected by protein kinase A or calcium/calmodulin-dependent protein kinase II antagonist. We conclude that activation of TRPV4 inhibits GABAA receptor, which may be mediated by activation of AMPK and subsequent down-regulation of PI3K/Akt signaling and activation of PKC signaling. Inhibition of GABAA receptors may account for the neuronal hyperexcitability caused by TRPV4 activation.
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Affiliation(s)
- Zhiwen Hong
- Department of Physiology, Nanjing Medical University Nanjing, China
| | - Yujing Tian
- Department of Physiology, Nanjing Medical University Nanjing, China
| | - Mengwen Qi
- Department of Physiology, Nanjing Medical University Nanjing, China
| | - Yingchun Li
- Department of Physiology, Nanjing Medical University Nanjing, China
| | - Yimei Du
- Research Center of Ion Channelopathy, Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Lei Chen
- Department of Physiology, Nanjing Medical University Nanjing, China
| | - Wentao Liu
- Department of Pharmacology, Nanjing Medical University Nanjing, China
| | - Ling Chen
- Department of Physiology, Nanjing Medical University Nanjing, China
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7
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Burgos-Vega C, Moy J, Dussor G. Meningeal afferent signaling and the pathophysiology of migraine. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:537-64. [PMID: 25744685 DOI: 10.1016/bs.pmbts.2015.01.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Migraine is the most common neurological disorder. Attacks are complex and consist of multiple phases but are most commonly characterized by intense, unilateral, throbbing headache. The pathophysiology contributing to migraine is poorly understood and the disorder is not well managed with currently available therapeutics, often rendering patients disabled during attacks. The mechanisms most likely to contribute to the pain phase of migraine require activation of trigeminal afferent signaling from the cranial meninges and subsequent relay of nociceptive information into the central nervous system in a region of the dorsal brainstem known as the trigeminal nucleus caudalis. Events leading to activation of meningeal afferents are unclear, but nerve endings within this tissue are mechanosensitive and also express a variety of ion channels including acid-sensing ion channels and transient receptor-potential channels. These properties may provide clues into the pathophysiology of migraine by suggesting that decreased extracellular pH and environmental irritant exposure in the meninges contributes to headache. Neuroplasticity is also likely to play a role in migraine given that attacks are triggered by routine events that are typically nonnoxious in healthy patients and clear evidence of sensitization occurs during an attack. Where and how plasticity develops is also not clear but may include events directly on the afferents and/or within the TNC. Among the mediators potentially contributing to plasticity, calcitonin gene-related peptide has received the most attention within the migraine field but other mechanisms may also contribute. Ultimately, greater understanding of the molecules and mechanisms contributing to migraine will undoubtedly lead to better therapeutics and relief for the large number of patients across the globe who suffer from this highly disabling neurological disorder.
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Affiliation(s)
- Carolina Burgos-Vega
- Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas, USA
| | - Jamie Moy
- Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas, USA
| | - Gregory Dussor
- Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas, USA.
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8
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Transient Receptor Potential Vanilloid 4-Induced Modulation of Voltage-Gated Sodium Channels in Hippocampal Neurons. Mol Neurobiol 2014; 53:759-768. [DOI: 10.1007/s12035-014-9038-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 11/30/2014] [Indexed: 02/03/2023]
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9
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Dussor G, Yan J, Xie JY, Ossipov MH, Dodick DW, Porreca F. Targeting TRP channels for novel migraine therapeutics. ACS Chem Neurosci 2014; 5:1085-96. [PMID: 25138211 PMCID: PMC4240253 DOI: 10.1021/cn500083e] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
![]()
Migraine is increasingly understood
to be a disorder of the brain.
In susceptible individuals, a variety of “triggers”
may influence altered central excitability, resulting in the activation
and sensitization of trigeminal nociceptive afferents surrounding
blood vessels (i.e., the trigeminovascular system), leading to migraine
pain. Transient receptor potential (TRP) channels are expressed in
a subset of dural afferents, including those containing calcitonin
gene related peptide (CGRP). Activation of TRP channels promotes excitation
of nociceptive afferent fibers and potentially lead to pain. In addition
to pain, allodynia to mechanical and cold stimuli can result from
sensitization of both peripheral afferents and of central pain pathways.
TRP channels respond to a variety of endogenous conditions including
chemical mediators and low pH. These channels can be activated by
exogenous stimuli including a wide range of chemical and environmental
irritants, some of which have been demonstrated to trigger migraine
in humans. Activation of TRP channels can elicit CGRP release, and
blocking the effects of CGRP through receptor antagonism or antibody
strategies has been demonstrated to be effective in the treatment
of migraine. Identification of approaches that can prevent activation
of TRP channels provides an additional novel strategy for discovery
of migraine therapeutics.
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Affiliation(s)
- Gregory Dussor
- School
of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, United States
| | - J. Yan
- Department
of Pharmacology, University of Washington, Seattle, Washington 98195, United States
| | - Jennifer Y. Xie
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
| | - Michael H. Ossipov
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
| | - David W. Dodick
- Department
of Neurology, Mayo Clinic Arizona, Phoenix, Arizona 85054, United States
| | - Frank Porreca
- Department
of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, United States
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10
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Nilius B, Szallasi A. Transient Receptor Potential Channels as Drug Targets: From the Science of Basic Research to the Art of Medicine. Pharmacol Rev 2014; 66:676-814. [DOI: 10.1124/pr.113.008268] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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11
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Li L, Yin J, Jie PH, Lu ZH, Zhou LB, Chen L, Chen L. Transient receptor potential vanilloid 4 mediates hypotonicity-induced enhancement of synaptic transmission in hippocampal slices. CNS Neurosci Ther 2013; 19:854-62. [PMID: 23826708 DOI: 10.1111/cns.12143] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 05/27/2013] [Accepted: 05/30/2013] [Indexed: 01/23/2023] Open
Abstract
AIM AND METHODS Changes in cerebrospinal fluid osmotic pressure modulate brain excitability. Transient receptor potential vanilloid 4 (TRPV4), which is sensitive to hypotonic stimulation, is expressed in hippocampus. The present study investigated the effect of hypotonic stimulation on hippocampal synaptic transmission and the role of TRPV4 in hypotonicity-action using electrophysiological recording and pharmacological technique. RESULTS Accompanied with the decrease in paired pulse facilitation, field excitatory postsynaptic potential (fEPSP) was enhanced by hypotonicity and TRPV4 agonist 4α-PDD in hippocampal slices, which was sensitive to TRPV4 antagonist HC-067047. Hypotonicity-induced increase in fEPSP was blocked by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist, but not N-methyl-d-aspartate receptor or N- or P/Q-type voltage-gated calcium channel antagonist. High voltage-gated calcium current (ICa ) in hippocampal CA3 pyramidal neurons was not affected by hypotonicity. AMPA-activated current (IAMPA ) in hippocampal CA1 pyramidal neurons was increased by hypotonicity and 4α-PDD, which was attenuated by HC-067047. Inhibition of protein kinase C or protein kinase A markedly attenuated hypotonicity-increased IAMPA , whereas antagonism of calcium/calmodulin-dependent protein kinase II had no such effect. CONCLUSION TRPV4 is involved in hypotonicity-induced enhancement of hippocampal synaptic transmission, which may be mediated through promoting presynaptic glutamate release and increasing postsynaptic AMPA receptor function.
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Affiliation(s)
- Lin Li
- Department of Physiology, Nanjing Medical University, Nanjing, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
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12
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Li L, Qu W, Zhou L, Lu Z, Jie P, Chen L, Chen L. Activation of Transient Receptor Potential Vanilloid 4 Increases NMDA-Activated Current in Hippocampal Pyramidal Neurons. Front Cell Neurosci 2013; 7:17. [PMID: 23459987 PMCID: PMC3586694 DOI: 10.3389/fncel.2013.00017] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 02/09/2013] [Indexed: 01/21/2023] Open
Abstract
The glutamate excitotoxicity, mediated through N-methyl-d-aspartate receptors (NMDARs), plays an important role in cerebral ischemia injury. Transient receptor potential vanilloid 4 (TRPV4) can be activated by multiple stimuli that may happen during stroke. The present study evaluated the effect of TRPV4 activation on NMDA-activated current (INMDA) and that of blocking TRPV4 on brain injury after focal cerebral ischemia in mice. We herein report that activation of TRPV4 by 4α-PDD and hypotonic stimulation increased INMDA in hippocampal CA1 pyramidal neurons, which was sensitive to TRPV4 antagonist HC-067047 and NMDAR antagonist AP-5, indicating that TRPV4 activation potentiates NMDAR response. In addition, the increase in INMDA by hypotonicity was sensitive to the antagonist of NMDAR NR2B subunit, but not of NR2A subunit. Furthermore, antagonists of calcium/calmodulin-dependent protein kinase II (CaMKII) significantly attenuated hypotonicity-induced increase in INMDA, while antagonists of protein kinase C or casein kinase II had no such effect, indicating that phosphorylation of NR2B subunit by CaMKII is responsible for TRPV4-potentiated NMDAR response. Finally, we found that intracerebroventricular injection of HC-067047 after 60 min middle cerebral artery occlusion reduced the cerebral infarction with at least a 12 h efficacious time-window. These findings indicate that activation of TRPV4 increases NMDAR function, which may facilitate glutamate excitotoxicity. Closing TRPV4 may exert potent neuroprotection against cerebral ischemia injury through many mechanisms at least including the prevention of NMDAR-mediated glutamate excitotoxicity.
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Affiliation(s)
- Lin Li
- Department of Physiology, Nanjing Medical University Nanjing, China ; State Key Laboratory of Reproductive Medicine, Nanjing Medical University Nanjing, China
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Abstract
Organisms exposed to altered salinity must be able to perceive osmolality change because metabolism has evolved to function optimally at specific intracellular ionic strength and composition. Such osmosensing comprises a complex physiological process involving many elements at organismal and cellular levels of organization. Input from numerous osmosensors is integrated to encode magnitude, direction, and ionic basis of osmolality change. This combinatorial nature of osmosensing is discussed with emphasis on fishes.
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Affiliation(s)
- Dietmar Kültz
- Department of Animal Science, Physiological Genomics Group, University of California, Davis, Davis, California
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Wei X, Edelmayer RM, Yan J, Dussor G. Activation of TRPV4 on dural afferents produces headache-related behavior in a preclinical rat model. Cephalalgia 2011; 31:1595-600. [PMID: 22049072 DOI: 10.1177/0333102411427600] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND The mechanisms contributing to the pain of migraine are poorly understood although activation of afferent nociceptors in the trigeminovascular system has been proposed as a key event. Prior studies have shown that dural-afferent nociceptors are sensitive to both osmotic and mechanical stimuli. Based on the sensitivity to these stimuli we hypothesized that dural afferents express the osmo/mechano-sensitive channel transient receptor-potential vanilloid 4 (TRPV4). METHODS These studies used in vitro patch-clamp electrophysiology of trigeminal neurons retrogradely labeled from the dura to examine the functional expression of TRPV4. Additionally, we used a rat headache model in which facial/hind paw allodynia following dural stimulation is measured to determine whether activation of meningeal TRPV4 produces responses consistent with migraine. RESULTS These studies found that 56% and 49% of identified dural afferents generate currents in response to hypotonic solutions and 4α-PDD, respectively. The response to these stimuli indicates that dural afferents express TRPV4. Activation of meningeal TPRV4 using hypotonic solution or 4α-PDD in vivo resulted in both facial and hind paw allodynia that was blocked by the TRPV4 antagonist RN1734. CONCLUSION These data indicate that activation of TRPV4 within the meninges produces afferent nociceptive signaling from the head that may contribute to migraine headache.
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Affiliation(s)
- Xiaomei Wei
- University of Arizona College of Medicine, Tucson, AZ 85724, USA
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Li L, Liu C, Chen L, Chen L. Hypotonicity modulates tetrodotoxin-sensitive sodium current in trigeminal ganglion neurons. Mol Pain 2011; 7:27. [PMID: 21496300 PMCID: PMC3094255 DOI: 10.1186/1744-8069-7-27] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 04/16/2011] [Indexed: 11/11/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) play an important role in the control of membrane excitability. We previously reported that the excitability of nociceptor was increased by hypotonic stimulation. The present study tested the effect of hypotonicity on tetrodotoxin-sensitive sodium current (TTX-S current) in cultured trigeminal ganglion (TG) neurons. Our data show that after hypotonic treatment, TTX-S current was increased. In the presence of hypotonicity, voltage-dependent activation curve shifted to the hyperpolarizing direction, while the voltage-dependent inactivation curve was not affected. Transient Receptor Potential Vanilloid 4 receptor (TRPV4) activator increased TTX-S current and hypotonicity-induced increase was markedly attenuated by TRPV4 receptor blockers. We also demonstrate that inhibition of PKC attenuated hypotonicity-induced inhibition, whereas PKA system was not involved in hypotonic-response. We conclude that hypotonic stimulation enhances TTX-S current, which contributes to hypotonicity-induced nociception. TRPV4 receptor and PKC intracellular pathway are involved in the increase of TTX-S current by hypotonicity.
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Affiliation(s)
- Lin Li
- Department of Physiology, Nanjing Medical University, Nanjing, PR China
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Wu LJ, Sweet TB, Clapham DE. International Union of Basic and Clinical Pharmacology. LXXVI. Current progress in the mammalian TRP ion channel family. Pharmacol Rev 2010; 62:381-404. [PMID: 20716668 DOI: 10.1124/pr.110.002725] [Citation(s) in RCA: 426] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Transient receptor potential (TRP) channels are a large family of ion channel proteins, surpassed in number in mammals only by voltage-gated potassium channels. TRP channels are activated and regulated through strikingly diverse mechanisms, making them suitable candidates for cellular sensors. They respond to environmental stimuli such as temperature, pH, osmolarity, pheromones, taste, and plant compounds, and intracellular stimuli such as Ca(2+) and phosphatidylinositol signal transduction pathways. However, it is still largely unknown how TRP channels are activated in vivo. Despite the uncertainties, emerging evidence using TRP channel knockout mice indicates that these channels have broad function in physiology. Here we review the recent progress on the physiology, pharmacology and pathophysiological function of mammalian TRP channels.
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Affiliation(s)
- Long-Jun Wu
- Howard Hughes Medical Institute, Department of Cardiology, Children's Hospital Boston, 320 Longwood Avenue, Boston, MA 02115, USA
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Luo AT, Luo HY, Hu XW, Gao LL, Liang HM, Tang M, Hescheler J. Hyposmotic challenge modulates function of L-type calcium channel in rat ventricular myocytes through protein kinase C. Acta Pharmacol Sin 2010; 31:1438-46. [PMID: 20953210 DOI: 10.1038/aps.2010.112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
AIM To study the effects and mechanisms by which hyposmotic challenge modulate function of L-type calcium current (I(Ca,L)) in rat ventricular myocytes. METHODS The whole-cell patch-clamp techniques were used to record I(Ca,L) in rat ventricular myocytes. RESULTS Hyposmotic challenge(∼220 mosmol/L) induced biphasic changes of I(Ca,L), a transient increase followed by a sustained decrease. I(Ca,L) increased by 19.1%±6.1% after short exposure (within 3 min) to hyposmotic solution. On the contrary, long hyposmotic challenge (10 min) decreased I(Ca,L) to 78.1%±11.0% of control, caused the inactivation of I(Ca,L), and shifted the steady-state inactivation curve of I(Ca,L) to the right. The decreased I(Ca,L) induced by hyposmotic swelling was reversed by isoproterenol or protein kinase A (PKA) activator foskolin. Hyposmotic swelling also reduced the stimulated I(Ca,L) by isoproterenol or foskolin. PKA inhibitor H-89 abolished swelling-induced transient increase of I(Ca,L), but did not affect the swelling-induced sustained decrease of I(Ca,L). NO donor SNAP and protein kinase G (PKG) inhibitor Rp-8-Br-PET-cGMPS did not interfere with swelling-induced biphasic changes of I(Ca,L). Protein kinase C (PKC) activator PMA decreased I(Ca,L) and hyposmotic solution with PMA reverted the decreased I(Ca,L) by PMA. PKC inhibitor BIM prevented the swelling-induced biphasic changes of I(Ca,L). CONCLUSION Hyposmotic challenge induced biphasic changes of I(Ca,L), a transient increase followed by a sustained decrease, in rat ventricular myocytes through PKC pathway, but not PKG pathway. PKA system could be responsible for the transient increase of I(Ca,L) during short exposure to hyposmotic solution.
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Petrofsky JS, Lawson D, Berk L, Suh H. Enhanced healing of diabetic foot ulcers using local heat and electrical stimulation for 30 min three times per week. J Diabetes 2010; 2:41-6. [PMID: 20923474 DOI: 10.1111/j.1753-0407.2009.00058.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Electrical stimulation (ES) with heating is effective in healing chronic wounds. However, it this effect due to ES alone or both heating and ES? The aim of the present study was to deduce the individual roles of heat and ES in the healing of chronic wounds. METHODS The study was performed on 20 patients (mean age 48.4 ± 14.6 years) with non-healing diabetic foot ulcers (mean duration 38.9 ± 23.7 months) who received local dry heat (37°C; n = 10) or local dry heat + ES (n = 10) three times a week for 4 weeks. Patients were given ES using biphasic sine wave stimulation (30 Hz, pulse width 250 μs, current approximately 20 mA). RESULTS Skin blood flow in and around the wound was measured with a laser Doppler flow imager. In the ES + heat group, the average wound area and volume decreased significantly by 68.4 ± 28.6% and 69.3 ± 27.1%, respectively (both P < 0.05), over the 1-month period. During the average session, blood flow increased to 102.3 ± 25.3% with local heat and to 152.3 ± 23.4% with ES + heat. In the group receiving treatment with local heat only, wounds that had not healed for at least 2 months showed 30.1 ± 22.6% healing (i.e. a decrease in wound area) after 1 month. Although this level of healing was significant, it was less than that observed in the ES + heat group (P<0.05). CONCLUSIONS Local dry heat and ES work well together to heal chronic diabetic foot wounds; however, local heat would appear to be a relevant part of this therapy because ES alone has produced little healing in previous studies.
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Suh H, Petrofsky JS, Lo T, Lawson D, Yu T, Pfeifer TM, Morawski T. The combined effect of a three-channel electrode delivery system with local heat on the healing of chronic wounds. Diabetes Technol Ther 2009; 11:681-8. [PMID: 19821762 DOI: 10.1089/dia.2009.0024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Historically, electrical stimulation (ES) has been used as a treatment for wound care. However, some studies show wounds healing with ES, whereas others do not. Part of the difficulty can be resolved by using heat to help dilate blood vessels, but an inherent problem with ES is uneven currents across the wound due to the use of only two electrodes. Therefore, we designed and tested a multi-electrode ES device in combination with local warming of the wound in non-healing chronic ulcers. STUDY DESIGN Eighteen subjects (mean +/- SD age, 35.7 +/- 21.3 years) with chronic ulcers (no healing for 26.1 +/- 24.6 months) received ES treatment three times a week for 4 weeks. A heat lamp was used before and during ES to keep the wound and area surrounding the wound warm (37 degrees C). ES was applied for 30 min with biphasic sine wave stimulation at a frequency of 30 Hz, pulse width of 250 micros, and current of about 20 mA. Skin blood flow (BF) in and around the wound was measured with a laser Doppler imager. Wound size was measured prior to each treatment. RESULTS Over the 1-month period, the mean wound area significantly decreased by 43.4 +/- 44.5% (P < 0.05), and wound volume decreased by 57.0 +/- 27.9% (P < 0.05). Skin BF significantly increased after application of ES and local heat (P < 0.05). The skin BF response decreased as time progressed and the wound healed. CONCLUSIONS Thus, in this pilot study, application of a three-channel ES system in combination with local heat is effective in the healing of non-healing chronic wounds. Future studies should examine a larger population with variables such as treatment duration, number of days, or length of treatment to optimize the effect of ES on healing of non-healing chronic wounds.
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Affiliation(s)
- Hyejin Suh
- Department of Physical Therapy, School of Allied Health Professions, Loma Linda University, Loma Linda, California 92350, USA
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Chen L, Liu C, Liu L. Osmolality-induced tuning of action potentials in trigeminal ganglion neurons. Neurosci Lett 2009; 452:79-83. [PMID: 19444958 DOI: 10.1016/j.neulet.2009.01.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The present study explored the effect of anisotonicity on action potential (AP) in cultured trigeminal ganglion (TG) neurons. We demonstrate that the number of evoked APs was increased by both hypo- and hypertonic treatment. Transient Receptor Potential Vanilloid 4 receptor (TRPV4) activator increased the number of APs, but only hypotonic-response was markedly blocked in TRPV4-/- mice. Additionally, inhibition of PKC attenuated hypotonicity-induced increase, whereas antagonism of PKA attenuated hypertonicity-response. We conclude that anisotonicity increases excitability of nociceptors, which might be involved in anisotonicity-induced nociception. The increase of APs by hypo- and hypertonicity is mediated through different receptor and intracellular signaling pathways.
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Affiliation(s)
- Lei Chen
- Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
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Suh H, Petrofsky J, Fish A, Hernandez V, Mendoza E, Collins K, Yang T, Abdul A, Batt J, Lawson D. A new electrode design to improve outcomes in the treatment of chronic non-healing wounds in diabetes. Diabetes Technol Ther 2009; 11:315-22. [PMID: 19425879 DOI: 10.1089/dia.2008.0092] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Chronic wounds are life-threatening in people with diabetes. Some studies show that electrical stimulation (ES) can help wounds heal, while others do not. But, ES is usually applied using a two-electrode system, where current distribution is greatest in the center line between the electrodes. In the present study, a three-electrode system (three-channel ES) was developed. Current dispersion on the skin and in the quadriceps muscle was compared between the conventional two-electrode and three-electrode systems in controls and tested for its ability to heal chronic wounds in people with diabetes. METHODS In controls, current was delivered via a biphasic sine wave at a frequency of 30 Hz and pulse width of 100 microseconds. Stimulation electrodes 5 cm x 5 cm and 5 cm x 10 cm were placed at 10 cm and 15 cm separation distances above the quadriceps muscle. Skin currents were measured using five pairs of surface electrodes positioned in five separate locations on the skin. Muscle currents were measured using three pairs of needle electrodes positioned in three different locations in the muscle belly. In chronic wounds in eight subjects with diabetes, stimulation was applied for 1 month, and healing and blood flow were measured. RESULTS Current during three-channel ES was dispersed more evenly and more deeply than with conventional two-channel ES (P < 0.05). In wounds, there was almost complete healing in 1 month, and current was uniform in the wound. CONCLUSIONS Three-channel ES is more effective than two-channel ES in terms of better current dispersion across the skin and penetration into tissue and will probably be better for wound healing.
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Affiliation(s)
- HyeJin Suh
- Department of Physical Therapy, Loma Linda University, Loma Linda, California 92350, USA
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Carreño FR, Ji LL, Cunningham JT. Altered central TRPV4 expression and lipid raft association related to inappropriate vasopressin secretion in cirrhotic rats. Am J Physiol Regul Integr Comp Physiol 2008; 296:R454-66. [PMID: 19091909 DOI: 10.1152/ajpregu.90460.2008] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Inappropriate vasopressin (AVP) release causes dilutional hyponatremia in many pathophysiological states such as cirrhosis. The central molecular mechanisms that mediate inappropriate AVP release are unknown. We tested the hypothesis that changes in the expression or trafficking of TRPV4 in the central nervous system may contribute to inappropriate AVP release in the bile duct ligation (BDL) model of cirrhosis in the rat. Four weeks after surgery, BDL rats demonstrated significantly increased plasma vasopressin and plasma renin activity (PRA), hypervolemia, and decreased plasma osmolality. These effects were blocked by providing BDL rats with 2% saline to drink for 15 days. TRPV4 protein expression was significantly increased in brain punches from BDL rats containing the supraoptic nucleus (SON) of the hypothalamus (100% +/- 11 to 157% +/- 4.8), and this effect was blocked in BDL rats given saline. Immunohistochemistry demonstrated a significant increase in TRPV4-positive cells and the percentage of AVP neurons that also were TRPV4-positive in the SON of BDL rats. In the hypothalamus of BDL rats, TRPV4 lipid raft association increased compared with sham (from 100% +/- 2.1 to 326.1% +/- 16). This effect was significantly attenuated in BDL rats given 2% saline to drink (174% +/- 11). In the brain stem, TRPV4 lipid raft association was reduced by BDL and inversely related to plasma AVP and PRA. We speculate that changes in TRPV4 expression and compartmentalization within lipid rafts could contribute to a feed-forward mechanism related to AVP release in cirrhosis.
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Affiliation(s)
- Flávia Regina Carreño
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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