scholarly journals Calcium transient evoked by TRPV1 activators is enhanced by tumor necrosis factor-α in rat pulmonary sensory neurons

2010 ◽  
Vol 299 (4) ◽  
pp. L483-L492 ◽  
Author(s):  
Youmin Hu ◽  
Qihai Gu ◽  
Ruei-Lung Lin ◽  
Richard Kryscio ◽  
Lu-Yuan Lee
Keyword(s):  
Sensory Neurons ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Allyl Isothiocyanate ◽  
Calcium Transient ◽  
Somatic Tissue ◽  
Dorsal Root Ganglion Neurons ◽  
Prolonged Treatment ◽  
Transient Receptor Potential Vanilloid ◽  
Ganglion Neurons

TNFα, a proinflammatory cytokine known to be involved in the pathogenesis of allergic asthma, has been shown to induce hyperalgesia in somatic tissue via a sensitizing effect on dorsal root ganglion neurons expressing transient receptor potential vanilloid type 1 receptor (TRPV1). Because TRPV1-expressing pulmonary sensory neurons play an important role in regulating airway function, this study was carried out to determine whether TNFα alters the sensitivity of these neurons to chemical activators. Responses of isolated nodose and jugular ganglion neurons innervating the rat lungs were determined by measuring the transient increase in intracellular Ca2+ concentration ([Ca2+]i). Our results showed the following. 1) A pretreatment with TNFα (50 ng/ml) for ∼24 h increased significantly the peak Δ[Ca2+]i evoked by capsaicin (Cap) in these neurons. A pretreatment with the same concentration of TNFα for a longer duration (∼48 h) did not further increase the response, but pretreatment for a shorter duration (1 h) or with a lower concentration (25 ng/ml, 24 h) failed to enhance the Cap sensitivity. 2) The same TNFα pretreatment also induced similar but less pronounced and less uniform increases in the responses to acid (pH 6.5–5.5), 2-aminoethoxydiphenyl borate (2-APB), a common activator of TRPV1, V2, and V3 channels, and allyl isothiocyanate (AITC), a selective activator of TRPA1 channel. 3) In sharp contrast, the responses to ATP, ACh, and KCl were not affected by TNFα. 4) The TNFα-induced hypersensitivity to Cap was not prevented by pretreatment with indomethacin (30 μM). 5) The immunoreactivity to both TNF receptor types 1 and 2 were detected in rat vagal pulmonary sensory neurons. In conclusion, prolonged treatment with TNFα induces a pronounced potentiating effect on the responses of isolated pulmonary sensory neurons to TRPV1 activators. This action of TNFα may contribute in part to the airway hyperresponsiveness induced by this cytokine.

scholarly journals Propofol Modulates Agonist-induced Transient Receptor Potential Vanilloid Subtype-1 Receptor Desensitization via  a Protein Kinase Cϵ-dependent Pathway in Mouse Dorsal Root Ganglion Sensory Neurons

2010 ◽  
Vol 113 (4) ◽  
pp. 833-844 ◽  
Author(s):  
Peter J. Wickley ◽  
Ryo Yuge ◽  
Mary S. Russell ◽  
Hongyu Zhang ◽  
Michael A. Sulak ◽  
...  
Keyword(s):  
Dorsal Root Ganglion ◽  
Sensory Neurons ◽  
Dorsal Root ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Dorsal Root Ganglion Neurons ◽  
Transient Receptor Potential Vanilloid ◽  
Wild Type ◽  
Transient Receptor ◽  
Ganglion Neurons

Background The activity of transient receptor potential vanilloid subtype-1 (TRPV1) receptors, key nociceptive transducers in dorsal root ganglion sensory neurons, is enhanced by protein kinase C epsilon (PKCepsilon) activation. The intravenous anesthetic propofol has been shown to activate PKCepsilon. Our objectives were to examine whether propofol modulates TRPV1 function in dorsal root ganglion neurons via activation of PKCepsilon. Methods Lumbar dorsal root ganglion neurons from wild-type and PKC& epsilon;-null mice were isolated and cultured for 24 h. Intracellular free Ca concentration was measured in neurons by using fura-2 acetoxymethyl ester. The duration of pain-associated behaviors was also assessed. Phosphorylation of PKCepsilon and TRPV1 and the cellular translocation of PKCepsilon from cytosol to membrane compartments were assessed by immunoblot analysis. Results In wild-type neurons, repeated stimulation with capsaicin (100 nm) progressively decreased the transient rise in intracellular free Ca concentration. After desensitization, exposure to propofol rescued the Ca response. The resensitizing effect of propofol was absent in neurons obtained from PKCepsilon-null mice. Moreover, the capsaicin-induced desensitization of TRPV1 was markedly attenuated in the presence of propofol in neurons from wild-type mice but not in neurons from PKCepsilon-null mice. Propofol also prolonged the duration of agonist-induced pain associated behaviors in wild-type mice. In addition, propofol increased phosphorylation of PKCepsilon as well as TRPV1 and stimulated translocation of PKCepsilon from cytosolic to membrane fraction. Discussion Our results indicate that propofol modulates TRPV1 sensitivity to capsaicin and that this most likely occurs through a PKCepsilon-mediated phosphorylation of TRPV1.

scholarly journals Long-Term Diabetic Microenvironment Augments the Decay Rate of Capsaicin-Induced Currents in Mouse Dorsal Root Ganglion Neurons

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 775
Author(s):  
Xingjuan Chen ◽  
Yaqian Duan ◽  
Ashley Riley ◽  
Megan Welch ◽  
Fletcher White ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Dorsal Root Ganglion ◽  
Patch Clamp ◽  
Dorsal Root ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Dorsal Root Ganglion Neurons ◽  
Transient Receptor Potential Vanilloid ◽  
Drg Neurons ◽  
Ganglion Neurons

Individuals with end-stage diabetic peripheral neuropathy present with decreased pain sensation. Transient receptor potential vanilloid type 1 (TRPV1) is implicated in pain signaling and resides on sensory dorsal root ganglion (DRG) neurons. We investigated the expression and functional activity of TRPV1 in DRG neurons of the Ins2+/Akita mouse at 9 months of diabetes using immunohistochemistry, live single cell calcium imaging, and whole-cell patch-clamp electrophysiology. 2′,7′-Dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence assay was used to determine the level of Reactive Oxygen Species (ROS) in DRGs. Although TRPV1 expressing neuron percentage was increased in Ins2+/Akita DRGs at 9 months of diabetes compared to control, capsaicin-induced Ca2+ influx was smaller in isolated Ins2+/Akita DRG neurons, indicating impaired TRPV1 function. Consistently, capsaicin-induced Ca2+ influx was decreased in control DRG neurons cultured in the presence of 25 mM glucose for seven days versus those cultured with 5.5 mM glucose. The high glucose environment increased cytoplasmic ROS accumulation in cultured DRG neurons. Patch-clamp recordings revealed that capsaicin-activated currents decayed faster in isolated Ins2+/Akita DRG neurons as compared to those in control neurons. We propose that in poorly controlled diabetes, the accelerated rate of capsaicin-sensitive TRPV1 current decay in DRG neurons decreases overall TRPV1 activity and contributes to peripheral neuropathy.

Effect of increasing temperature on TRPV1-mediated responses in isolated rat pulmonary sensory neurons

2008 ◽  
Vol 294 (3) ◽  
pp. L563-L571 ◽  
Author(s):  
Dan Ni ◽  
Lu-Yuan Lee
Keyword(s):  
Sensory Neurons ◽  
Transient Receptor Potential ◽  
Direct Action ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Trpv1 Channel ◽  
Positive Interaction ◽  
C Fibers ◽  
Ganglion Neurons ◽  
Increasing Temperature

Hyperthermia has been shown to sensitize vagal pulmonary C-fibers in anesthetized rats. However, it was not clear whether the effect was due to a direct action of hyperthermia on these sensory neurons. To answer this question, we carried out this study to determine the effect of increasing temperature on the responses to various chemical stimuli in isolated nodose and jugular ganglion neurons innervating the rat lungs. In the whole cell perforated patch-clamp study, when the temperature was increased from normal (∼36°C) to hyperthermic (∼40.6°C) level of the rat body temperature, the inward currents evoked by capsaicin, a selective activator of the transient receptor potential vanilloid type 1 (TRPV1), and 2-aminoethoxydiphenyl borate (2-APB), a nonselective activator of TRPV1–3 receptors, were both significantly increased. This potentiating effect was clearly present even at a moderate level of hyperthermia (∼39°C). However, only the slow, sustained component of acid-evoked current mediated through the TRPV1 receptor was potentiated by hyperthermia, whereas the rapid, transient component was inhibited. In contrast, the currents evoked by adenosine 5′-triphosphate and acetylcholine, neither of which is known to activate the TRPV1 channel, did not increase when the same temperature elevation was applied. Furthermore, the hyperthermia-induced potentiation of the cell response to 2-APB was significantly attenuated by either capsazepine or AMG 9810, selective TRPV1 antagonists. In conclusion, increasing temperature within the physiological range exerts a potentiating effect on the response to TRPV1 activators in these neurons, which is probably mediated through a positive interaction between hyperthermia and these chemical activators at the TRPV1 channel.

scholarly journals Pain-enhancing mechanism through interaction between TRPV1 and anoctamin 1 in sensory neurons

2015 ◽  
Vol 112 (16) ◽  
pp. 5213-5218 ◽  
Author(s):  
Yasunori Takayama ◽  
Daisuke Uta ◽  
Hidemasa Furue ◽  
Makoto Tominaga
Keyword(s):  
Action Potential ◽  
Sensory Neurons ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Concomitant Administration ◽  
Dorsal Root Ganglion Neurons ◽  
Dependent Manner ◽  
High Concentration ◽  
Anoctamin 1 ◽  
Ganglion Neurons

The capsaicin receptor transient receptor potential cation channel vanilloid 1 (TRPV1) is activated by various noxious stimuli, and the stimuli are converted into electrical signals in primary sensory neurons. It is believed that cation influx through TRPV1 causes depolarization, leading to the activation of voltage-gated sodium channels, followed by the generation of action potential. Here we report that the capsaicin-evoked action potential could be induced by two components: a cation influx-mediated depolarization caused by TRPV1 activation and a subsequent anion efflux-mediated depolarization via activation of anoctamin 1 (ANO1), a calcium-activated chloride channel, resulting from the entry of calcium through TRPV1. The interaction between TRPV1 and ANO1 is based on their physical binding. Capsaicin activated the chloride currents in an extracellular calcium-dependent manner in HEK293T cells expressing TRPV1 and ANO1. Similarly, in mouse dorsal root ganglion neurons, capsaicin-activated inward currents were inhibited significantly by a specific ANO1 antagonist, T16Ainh-A01 (A01), in the presence of a high concentration of EGTA but not in the presence of BAPTA [1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid]. The generation of a capsaicin-evoked action potential also was inhibited by A01. Furthermore, pain-related behaviors in mice treated with capsaicin, but not with αβ-methylene ATP, were reduced significantly by the concomitant administration of A01. These results indicate that TRPV1–ANO1 interaction is a significant pain-enhancing mechanism in the peripheral nervous system.

CDK5 inhibits the clathrin-dependent internalization of TRPV1 by phosphorylating the clathrin adaptor protein AP2μ2

2019 ◽  
Vol 12 (585) ◽  
pp. eaaw2040 ◽  
Author(s):  
Jiao Liu ◽  
Junxia Du ◽  
Yun Wang
Keyword(s):  
Drug Targets ◽  
Transient Receptor Potential ◽  
Phosphorylation Site ◽  
Thermal Hyperalgesia ◽  
Adaptor Protein ◽  
Receptor Potential ◽  
Dorsal Root Ganglion Neurons ◽  
Transient Receptor Potential Vanilloid ◽  
Transient Receptor ◽  
Ganglion Neurons

Transient receptor potential vanilloid 1 (TRPV1), a nonselective, ligand-gated cation channel, responds to multiple noxious stimuli and is targeted by many kinases that influence its trafficking and activity. Studies on the internalization of TRPV1 have mainly focused on that induced by capsaicin or other agonists. Here, we report that constitutive internalization of TRPV1 occurred in a manner dependent on clathrin, dynamin, and adaptor protein complex 2 (AP2). The μ2 subunit of AP2 (AP2μ2) interacted directly with TRPV1 and was required for its constitutive internalization. Cyclin-dependent kinase 5 (CDK5) phosphorylated AP2μ2 at Ser45, which reduced the interaction between TRPV1 and AP2μ2, leading to decreased TRPV1 internalization. Intrathecal delivery of a cell-penetrating fusion peptide corresponding to the Cdk5 phosphorylation site in AP2μ2, which competed with AP2μ2 for phosphorylation by Cdk5, increased the abundance of TRPV1 on the surface of dorsal root ganglion neurons and reduced complete Freund’s adjuvant (CFA)–induced inflammatory thermal hyperalgesia in rats. In addition to describing a mechanism of TRPV1 constitutive internalization and its inhibition by CDK5, these findings demonstrate that CDK5 promotes inflammatory thermal hyperalgesia by reducing TRPV1 internalization, providing previously unidentified insights into the search for drug targets to treat pain.

scholarly journals Attenuation of TRPV1 and TRPV4 Expression and Function in Mouse Inflammatory Pain Models Using Electroacupuncture

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Wei-Hsin Chen ◽  
Jason T. C. Tzen ◽  
Ching Liang Hsieh ◽  
Yung Hsiang Chen ◽  
Tzu-Jou Lin ◽  
...  
Keyword(s):  
Inflammatory Pain ◽  
Transient Receptor Potential ◽  
Thermal Hyperalgesia ◽  
Receptor Potential ◽  
Dorsal Root Ganglion Neurons ◽  
Transient Receptor Potential Vanilloid ◽  
Pain Mechanisms ◽  
Electrophysiological Properties ◽  
Pain Models ◽  
Ganglion Neurons

Although pain is a major human affliction, our understanding of pain mechanisms is limited. TRPV1 (transient receptor potential vanilloid subtype 1) and TRPV4 are two crucial receptors involved in inflammatory pain, but their roles in EA- (electroacupuncture-) mediated analgesia are unknown. We injected mice with carrageenan (carra) or a complete Freund’s adjuvant (CFA) to model inflammatory pain and investigated the analgesic effect of EA using animal behavior tests, immunostaining, Western blotting, and a whole-cell recording technique. The inflammatory pain model mice developed both mechanical and thermal hyperalgesia. Notably, EA at the ST36 acupoint reversed these phenomena, indicating its curative effect in inflammatory pain. The protein levels of TRPV1 and TRPV4 in DRG (dorsal root ganglion) neurons were both increased at day 4 after the initiation of inflammatory pain and were attenuated by EA, as demonstrated by immunostaining and Western blot analysis. We verified DRG electrophysiological properties to confirm that EA ameliorated peripheral nerve hyperexcitation. Our results indicated that the AP (action potential) threshold, rise time, and fall time, and the percentage and amplitude of TRPV1 and TRPV4 were altered by EA, indicating that EA has an antinociceptive role in inflammatory pain. Our results demonstrate a novel role for EA in regulating TRPV1 and TRPV4 protein expression and nerve excitation in mouse inflammatory pain models.

scholarly journals Molecular Basis of Cav2.3 Calcium Channels in Rat Nociceptive Neurons

2006 ◽  
Vol 282 (7) ◽  
pp. 4757-4764 ◽  
Author(s):  
Zhi Fang ◽  
Chul-Kyu Park ◽  
Hai Ying Li ◽  
Hyun Yeong Kim ◽  
Seong-Hae Park ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Single Cell ◽  
Sensory Neurons ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Rt Pcr ◽  
Nociceptive Neurons ◽  
Transient Receptor ◽  
Ganglion Neurons

Cav2.3 calcium channels play an important role in pain transmission in peripheral sensory neurons. Six Cav2.3 isoforms resulting from different combinations of three inserts (inserts I and II in the II–III loop and insert III in the carboxyl-terminal region) have been identified in different mammalian tissues. To date, however, Cav2.3 isoforms unique to primary sensory neurons have not been identified. In this study, we determined Cav2.3 isoforms expressed in the rat trigeminal ganglion neurons. Whole tissue reverse transcription (RT)-PCR analyses revealed that only two isoforms, Cav2.3a and Cav2.3e, are present in TG neurons. Using single cell RT-PCR, we found that Cav2.3e is the major isoform, whereas Cav2.3e expression is highly restricted to small (<16 μm) isolectin B4-negative and tyrosine kinase A-positive neurons. Cav2.3e was also preferentially detected in neurons expressing the nociceptive marker, transient receptor potential vanilloid 1. Single cell RT-PCR following calcium imaging and whole-cell patch clamp recordings provided evidence of an association between an R-type calcium channel component and Cav2.3e expression. Our results suggest that Cav2.3e in sensory neurons may be a potential target for the treatment of pain.

scholarly journals Systemic QX-314 Reduces Bone Cancer Pain through Selective Inhibition of Transient Receptor Potential Vanilloid Subfamily 1–expressing Primary Afferents in Mice

2016 ◽  
Vol 125 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Satoshi Fuseya ◽  
Katsumi Yamamoto ◽  
Hitoshi Minemura ◽  
Satoshi Yamaori ◽  
Tomoyuki Kawamata ◽  
...  
Keyword(s):  
Cancer Pain ◽  
Transient Receptor Potential ◽  
Bone Cancer ◽  
Receptor Potential ◽  
Adenosine Monophosphate ◽  
Selective Inhibition ◽  
Dorsal Root Ganglion Neurons ◽  
Bone Cancer Pain ◽  
Transient Receptor Potential Vanilloid ◽  
Ganglion Neurons

Abstract Background The aim of this study was to determine whether systemic administration of QX-314 reduces bone cancer pain through selective inhibition of transient receptor potential vanilloid subfamily 1 (TRPV1)–expressing afferents. Methods A mouse model of bone cancer pain was used. The authors examined the effects of bolus (0.01 to 3 mg/kg, n = 6 to 10) and continuous (5 mg kg−1 h−1, n = 5) administration of QX-314 on both bone cancer pain–related behaviors and phosphorylated cyclic adenosine monophosphate response element–binding protein expression in dorsal root ganglion neurons (n = 3 or 6) and the effects of ablation of TRPV1-expressing afferents on bone cancer pain–related behaviors (n = 10). Results The numbers of flinches indicative of ongoing pain in QX-314–treated mice were smaller than those in vehicle-treated mice at 10 min (3 mg/kg, 4 ± 3; 1 mg/kg, 5 ± 3 vs. 12 ± 3; P &lt; 0.001; n = 8 to 9), 24 h (3 ± 2 vs. 13 ± 3, P &lt; 0.001), and 48 h (4 ± 1 vs. 12 ± 2, P &lt; 0.001; n = 5 in each group) after QX-314 administration, but impaired limb use, weight-bearing including that examined by the CatWalk system, and rotarod performance indicative of movement-evoked pain were comparable. QX-314 selectively inhibited the increase in phosphorylated cyclic adenosine monophosphate response element–binding protein expression in TRPV1-positive, but not in TRPV1-negative, dorsal root ganglion neurons compared to that in the case of vehicle administration (32.2 ± 3.0% vs. 52.6 ± 5.9%, P &lt; 0.001; n = 6 in each group). Ablation of TRPV1-expressing afferents mimicked the effects of QX-314. Conclusion This study showed that systemic administration of QX-314 in mice inhibits some behavioral aspects of bone cancer pain through selective inhibition of TRPV1-expressing afferents without coadministration of TRPV1 agonists.

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