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Shehab S, Javed H, Johnson AM, Tariq S, Kumar CA, Emerald BS. Unveiling the mechanisms of neuropathic pain suppression: perineural resiniferatoxin targets Trpv1 and beyond. Front Neuroanat 2023; 17:1306180. [PMID: 38099210 PMCID: PMC10720729 DOI: 10.3389/fnana.2023.1306180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/10/2023] [Indexed: 12/17/2023] Open
Abstract
Neuropathic pain arises from damage or disorders affecting the somatosensory system. In rats, L5 nerve injury induces thermal and mechanical hypersensitivity/hyperalgesia. Recently, we demonstrated that applying resiniferatoxin (RTX) directly on uninjured L3 and L4 nerves alleviated thermal and mechanical hypersensitivity resulting from L5 nerve injury. Herein, using immunohistochemistry, Western blot, and qRT-PCR techniques, we reveal that perineural application of RTX (0.002%) on the L4 nerve substantially downregulated the expression of its receptor (Trpv1) and three different voltage-gated ion channels (Nav1.9, Kv4.3, and Cav2.2). These channels are found primarily in small-sized neurons and show significant colocalization with Trpv1 in the dorsal root ganglion (DRG). However, RTX treatment did not affect the expression of Kv1.1, Piezo2 (found in large-sized neurons without colocalization with Trpv1), and Kir4.1 (localized in satellite cells) in the ipsilateral DRGs. Furthermore, RTX application on L3 and L4 nerves reduced the activation of c-fos in the spinal neurons induced by heat stimulation. Subsequently, we investigated whether applying RTX to the L3 and L4 nerves 3 weeks before the L5 nerve injury could prevent the onset of neuropathic pain. Both 0.002 and 0.004% concentrations of RTX produced significant analgesic effects, while complete prevention of thermal and mechanical hypersensitivity required a concentration of 0.008%. Importantly, this preventive effect on neuropathic manifestations was not associated with nerve degeneration, as microscopic examination revealed no morphological changes. Overall, this study underscores the mechanisms and the significance of perineural RTX treatment applied to adjacent uninjured nerves in entirely preventing nerve injury-induced neuropathic pain in humans and animals.
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Affiliation(s)
- Safa Shehab
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
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Association of Non-Dipping Blood Pressure Patterns with Diabetic Peripheral Neuropathy: A Cross-Sectional Study among a Population with Diabetes in Greece. Nutrients 2022; 15:nu15010072. [PMID: 36615728 PMCID: PMC9824387 DOI: 10.3390/nu15010072] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/11/2022] [Accepted: 12/15/2022] [Indexed: 12/28/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) is present in 20-50% of cases with diabetes. The pathophysiology of DPN is not yet clear regarding hypertension (HTN). The aim of this study was to assess the association between the stages of DPN and HTN in a Greek population with diabetes. We examined 102 adults for diabetic neuropathy (DPN) from November 2020 to December 2021, using the Toronto Clinical Neuropathy Scale System (TCNSS) to categorize them into two groups (no/mild DPN versus medium/severe DPN). Ambulatory blood pressure monitoring was performed to evaluate their hypertensive status. Univariate and multivariate logistic regression analyses were performed to assess the association between the stage of DPN and HTN. The multivariate analysis, considering sex, age, and dipping status, did not show statistically significant associations between stages of HTN and DPN. However, in contrast to dippers, non-dippers had an almost four-times higher risk of developing medium-to-severe DPN (odds ratio (OR) 3.93; 95% confidence interval (CI) [1.33-11.64]); females, in contrast to males, had a 65% lower risk of developing moderate/severe DPN (OR 0.35; 95%CI [0.14-0.92]). In conclusion, our findings showed no statistically significant associations between DPN and HTN; however, dipping status, hyperglycemia, and female sex were shown to play a role in the pathophysiology of DPN.
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Javed H, Johnson AM, Challagandla AK, Emerald BS, Shehab S. Cutaneous Injection of Resiniferatoxin Completely Alleviates and Prevents Nerve-Injury-Induced Neuropathic Pain. Cells 2022; 11:cells11244049. [PMID: 36552812 PMCID: PMC9776507 DOI: 10.3390/cells11244049] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/29/2022] [Accepted: 12/09/2022] [Indexed: 12/16/2022] Open
Abstract
Fifth lumbar (L5) nerve injury in rodent produces neuropathic manifestations in the corresponding hind paw. The aim of this study was to investigate the effect of cutaneous injection of resiniferatoxin (RTX), a TRPV1 receptor agonist, in the rat's hind paw on the neuropathic pain induced by L5 nerve injury. The results showed that intraplantar injection of RTX (0.002%, 100 µL) (1) completely reversed the development of chronic thermal and mechanical hypersensitivity; (2) completely prevented the development of nerve-injury-induced thermal and mechanical hypersensitivity when applied one week earlier; (3) caused downregulation of nociceptive pain markers, including TRPV1, IB4 and CGRP, and upregulation of VIP in the ipsilateral dorsal horn of spinal cord and dorsal root ganglion (DRG) immunohistochemically and a significant reduction in the expression of TRPV1 mRNA and protein in the ipsilateral DRG using Western blot and qRT-PCR techniques; (4) caused downregulation of PGP 9.5- and CGRP-immunoreactivity in the injected skin; (5) produced significant suppression of c-fos expression, as a neuronal activity marker, in the spinal neurons in response to a second intraplantar RTX injection two weeks later. This work identifies the ability of cutaneous injection of RTX to completely alleviate and prevent the development of different types of neuropathic pain in animals and humans.
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Hori A, Hotta N, Fukazawa A, Estrada JA, Katanosaka K, Mizumura K, Sato J, Ishizawa R, Kim HK, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA, Mizuno M. Insulin potentiates the response to capsaicin in dorsal root ganglion neurons in vitro and muscle afferents ex vivo in normal healthy rodents. J Physiol 2022; 600:531-545. [PMID: 34967443 PMCID: PMC8810710 DOI: 10.1113/jp282740] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/23/2021] [Indexed: 02/03/2023] Open
Abstract
Systemic insulin administration evokes sympathoexcitatory actions, but the mechanisms underlying these observations are unknown. We reported that insulin sensitizes the response of thin-fibre primary afferents, as well as the dorsal root ganglion (DRG) that subserves them, to mechanical stimuli. However, little is known about the effects of insulin on primary neuronal responses to chemical stimuli. TRPV1, whose agonist is capsaicin (CAP), is widely expressed on chemically sensitive metaboreceptors and/or nociceptors. The aim of this investigation was to determine the effects of insulin on CAP-activated currents in small DRG neurons and CAP-induced action potentials in thin-fibre muscle afferents of normal healthy rodents. Additionally, we investigated whether insulin potentiates sympathetic nerve activity (SNA) responses to CAP. In whole-cell patch-clamp recordings from cultured mice DRG neurons in vitro, the fold change in CAP-activated current from pre- to post-application of insulin (n = 13) was significantly (P < 0.05) higher than with a vehicle control (n = 14). Similar results were observed in single-fibre recording experiments ex vivo as insulin potentiated CAP-induced action potentials compared to vehicle controls (n = 9 per group, P < 0.05). Furthermore, insulin receptor blockade with GSK1838705 significantly suppressed the insulin-induced augmentation in CAP-activated currents (n = 13) as well as the response magnitude of CAP-induced action potentials (n = 9). Likewise, the renal SNA response to CAP after intramuscular injection of insulin (n = 8) was significantly (P < 0.05) greater compared to vehicle (n = 9). The findings suggest that insulin potentiates TRPV1 responsiveness to CAP at the DRG and muscle tissue levels, possibly contributing to the augmentation in sympathoexcitation during activities such as physical exercise. KEY POINTS: Evidence suggests insulin centrally activates the sympathetic nervous system, and a chemical stimulus to tissues activates the sympathetic nervous system via thin fibre muscle afferents. Insulin is reported to modulate putative chemical-sensitive channels in the dorsal root ganglion neurons of these afferents. In the present study, it is demonstrated that insulin potentiates the responsiveness of thin fibre afferents to capsaicin at muscle tissue levels as well as at the level of dorsal root ganglion neurons. In addition, it is demonstrated that insulin augments the sympathetic nerve activity response to capsaicin in vivo. These data suggest that sympathoexcitation is peripherally mediated via insulin-induced chemical sensitization. The present study proposes a possible physiological role of insulin in the regulation of chemical sensitivity in somatosensory thin fibre muscle afferents.
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Affiliation(s)
- Amane Hori
- Graduate School of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan;,Japan Society for the Promotion of Science, Tokyo 102-8472, Japan
| | - Norio Hotta
- Graduate School of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan;,College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Ayumi Fukazawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Juan A. Estrada
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kimiaki Katanosaka
- Graduate School of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan;,College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Kazue Mizumura
- Department of Physiology, Nihon University School of Dentistry, Tokyo 101-8310, Japan
| | - Jun Sato
- Graduate School of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan;,College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gary A. Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jere H. Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Scott A. Smith
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Rosta J, Tóth M, Friedrich N, Sántha P, Jancsó G, Dux M. Insulin sensitizes neural and vascular TRPV1 receptors in the trigeminovascular system. J Headache Pain 2022; 23:7. [PMID: 35033025 PMCID: PMC8903670 DOI: 10.1186/s10194-021-01380-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/28/2021] [Indexed: 11/17/2022] Open
Abstract
Background Clinical observations suggest that hyperinsulinemia and insulin resistance can be associated with migraine headache. In the present study we examined the effect of insulin on transient receptor potential vanilloid 1 (TRPV1) receptor-dependent meningeal nociceptor functions in rats. Methods The effects of insulin on the TRPV1 receptor stimulation-induced release of calcitonin gene related peptide (CGRP) from trigeminal afferents and changes in meningeal blood flow were studied. Colocalization of the insulin receptor, the TRPV1 receptor and CGRP was also analyzed in trigeminal ganglion neurons. Results Insulin induced release of CGRP from meningeal afferents and consequent increases in dural blood flow through the activation of TRPV1 receptors of trigeminal afferents. Insulin sensitized both neural and vascular TRPV1 receptors making them more susceptible to the receptor agonist capsaicin. Immunohistochemistry revealed colocalization of the insulin receptor with the TRPV1 receptor and CGRP in a significant proportion of trigeminal ganglion neurons. Conclusions Insulin may activate or sensitize meningeal nociceptors that may lead to enhanced headache susceptibility in persons with increased plasma insulin concentration.
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Affiliation(s)
- Judit Rosta
- Department of Physiology, University of Szeged, Dóm tér 10, Szeged, H-6720, Hungary
| | - Máté Tóth
- Department of Physiology, University of Szeged, Dóm tér 10, Szeged, H-6720, Hungary
| | - Nadine Friedrich
- Department of Physiology, University of Szeged, Dóm tér 10, Szeged, H-6720, Hungary
| | - Péter Sántha
- Department of Physiology, University of Szeged, Dóm tér 10, Szeged, H-6720, Hungary
| | - Gábor Jancsó
- Department of Physiology, University of Szeged, Dóm tér 10, Szeged, H-6720, Hungary
| | - Mária Dux
- Department of Physiology, University of Szeged, Dóm tér 10, Szeged, H-6720, Hungary.
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6
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Mizuno M, Hotta N, Ishizawa R, Kim HK, Iwamoto G, Vongpatanasin W, Mitchell JH, Smith SA. The Impact of Insulin Resistance on Cardiovascular Control During Exercise in Diabetes. Exerc Sport Sci Rev 2021; 49:157-167. [PMID: 33965976 PMCID: PMC8195845 DOI: 10.1249/jes.0000000000000259] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Patients with diabetes display heightened blood pressure response to exercise, but the underlying mechanism remains to be elucidated. There is no direct evidence that insulin resistance (hyperinsulinemia or hyperglycemia) impacts neural cardiovascular control during exercise. We propose a novel paradigm in which hyperinsulinemia or hyperglycemia significantly influences neural regulatory pathways controlling the circulation during exercise in diabetes.
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Affiliation(s)
- Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Norio Hotta
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Gary Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Jere H. Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Scott A. Smith
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
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7
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Ide S, Kawamata T, Ishida K, Fuseya S, Ishida T, Sugiyama Y, Kawamata M, Tanaka S. Phospholipase Cβ3 Expressed in Mouse DRGs is Involved in Inflammatory and Postoperative Pain. J Pain Res 2020; 13:3371-3384. [PMID: 33335421 PMCID: PMC7737028 DOI: 10.2147/jpr.s280565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022] Open
Abstract
Background Previous studies suggested that phospholipase Cβ3 (PLCβ3), which is a common downstream component in the signaling cascade, plays an important role in peripheral mechanisms of perception including nociception. However, detailed profiles of PLCβ3-expressing dorsal root ganglion (DRG) neurons and involvement of PLCβ3 in inflammatory and postoperative pain have not been fully investigated. Purpose We evaluated neurochemical char0acteristics of PLCβ3-expressing DRG neurons in mice and then we examined the effects of selective knockdown of PLCβ3 expression in DRGs on inflammatory and postoperative pain. Methods Male C57BL/6-strain mice were used. For the inflammatory model, each mouse received subcutaneous injection of complete Freund’s adjuvant (CFA) in the left hindpaw. For the postoperative pain model, a plantar incision was made in the left hindpaw. PLCβ3 antisense oligodeoxynucleotide or PLCβ3 mismatch oligodeoxynucleotide was intrathecally administered once a day for three consecutive days in each model. The time courses of thermal hyperalgesia and mechanical hyperalgesia were investigated. Changes in PLCβ3 protein levels in DRGs were evaluated by Western blotting. Results Immunohistochemical analysis showed that high proportion of the PLCβ3-positive profiles were biotinylated isolectin B4-positive or transient receptor potential vanilloid subfamily 1-positive. PLCβ3 protein level in DRGs during CFA-induced inflammation was comparable to that at baseline. Intrathecal administration of PLCβ3 antisense oligodeoxynucleotide, which significantly suppressed PLCβ3 expression in DRGs, did not affect pain thresholds in normal conditions but inhibited CFA-induced thermal and mechanical hyperalgesia both at the early and late phases compared to that in mismatch oligodeoxynucleotide-treated mice. Intrathecal administration of PLCβ3 antisense oligodeoxynucleotide also inhibited surgical incision-induced thermal and mechanical hyperalgesia. Conclusion Our results uncover a unique role of PLCβ3 in the development and maintenance of inflammatory pain induced by CFA application and in those of surgical incision-induced pain, although PLCβ3 does not play a major role in thermal nociception or mechanical nociception in normal conditions.
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Affiliation(s)
- Susumu Ide
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Tomoyuki Kawamata
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.,Department of Anesthesiology, Wakayama Medical University, Wakayama, Japan
| | - Kumiko Ishida
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Satoshi Fuseya
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Takashi Ishida
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Yuki Sugiyama
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Mikito Kawamata
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Satoshi Tanaka
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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Lázár BA, Jancsó G, Sántha P. Modulation of Sensory Nerve Function by Insulin: Possible Relevance to Pain, Inflammation and Axon Growth. Int J Mol Sci 2020; 21:ijms21072507. [PMID: 32260335 PMCID: PMC7177741 DOI: 10.3390/ijms21072507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 12/16/2022] Open
Abstract
Insulin, besides its pivotal role in energy metabolism, may also modulate neuronal processes through acting on insulin receptors (InsRs) expressed by neurons of both the central and the peripheral nervous system. Recently, the distribution and functional significance of InsRs localized on a subset of multifunctional primary sensory neurons (PSNs) have been revealed. Systematic investigations into the cellular electrophysiology, neurochemistry and morphological traits of InsR-expressing PSNs indicated complex functional interactions among specific ion channels, proteins and neuropeptides localized in these neurons. Quantitative immunohistochemical studies have revealed disparate localization of the InsRs in somatic and visceral PSNs with a dominance of InsR-positive neurons innervating visceral organs. These findings suggested that visceral spinal PSNs involved in nociceptive and inflammatory processes are more prone to the modulatory effects of insulin than somatic PSNs. Co-localization of the InsR and transient receptor potential vanilloid 1 (TRPV1) receptor with vasoactive neuropeptides calcitonin gene-related peptide and substance P bears of crucial importance in the pathogenesis of inflammatory pathologies affecting visceral organs, such as the pancreas and the urinary bladder. Recent studies have also revealed significant novel aspects of the neurotrophic propensities of insulin with respect to axonal growth, development and regeneration.
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Affiliation(s)
- Bence András Lázár
- Department of Psychiatry, University of Szeged, H-6725 Szeged, Hungary
- Correspondence:
| | - Gábor Jancsó
- Department of Physiology, University of Szeged, H-6720 Szeged, Hungary; (G.J.); (P.S.)
| | - Péter Sántha
- Department of Physiology, University of Szeged, H-6720 Szeged, Hungary; (G.J.); (P.S.)
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9
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Javed H, Rehmathulla S, Tariq S, Emerald BS, Ljubisavljevic M, Shehab S. Perineural application of resiniferatoxin on uninjured L3 and L4 nerves completely alleviates thermal and mechanical hypersensitivity following L5 nerve injury in rats. J Comp Neurol 2020; 528:2195-2217. [PMID: 32064609 DOI: 10.1002/cne.24884] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 12/21/2022]
Abstract
Fifth lumbar (L5) nerve injury in rats causes neuropathic pain manifested with thermal and mechanical hypersensitivity in the ipsilateral hind paw. This study aimed to determine whether the elimination of unmyelinated primary afferents of the adjacent uninjured nerves (L3 and L4) would alleviate peripheral neuropathic pain. Different concentrations of capsaicin or its analog, resiniferatoxin (RTX), were applied perineurally on either the left L4 or L3 and L4 nerves in Wistar rats whose left L5 nerves were ligated and cut. The application of both capsaicin and RTX on the L4 nerve significantly reduced both thermal and mechanical hypersensitivity. However, only the application of RTX on both L3 and L4 nerves completely alleviated all neuropathic manifestations. Interestingly, responses to thermal and mechanical stimuli were preserved, despite RTX application on uninjured L3, L4, and L5 nerves, which supply the plantar skin in rats. Perineural application of RTX caused downregulation of TRPV1, CGRP, and IB4 binding and upregulation of VIP in the corresponding dorsal root ganglia (DRG) and the dorsal horn of the spinal cord. In comparison, VGLUT1 and NPY immunoreactivities were not altered. RTX application did not cause degenerative or ultrastructural changes in the treated nerves and corresponding DRGs. The results demonstrate that RTX induces neuroplasticity, rather than structural changes in primary afferents, that are responsible for alleviating hypersensitivity and chronic pain. Furthermore, this study suggests that treating uninjured adjacent spinal nerves may be used to manage chronic neuropathic pain following peripheral nerve injury.
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Affiliation(s)
- Hayate Javed
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Sumisha Rehmathulla
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Saeed Tariq
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Bright S Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Milos Ljubisavljevic
- Department of Physiology, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Safa Shehab
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates.,Zayed Center for Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
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10
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Hotta N, Katanosaka K, Mizumura K, Iwamoto GA, Ishizawa R, Kim HK, Vongpatanasin W, Mitchell JH, Smith SA, Mizuno M. Insulin potentiates the response to mechanical stimuli in small dorsal root ganglion neurons and thin fibre muscle afferents in vitro. J Physiol 2019; 597:5049-5062. [PMID: 31468522 DOI: 10.1113/jp278527] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 08/27/2019] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS Insulin is known to activate the sympathetic nervous system centrally. A mechanical stimulus to tissues activates the sympathetic nervous system via thin fibre afferents. Evidence suggests that insulin modulates putative mechanosensitive channels in the dorsal root ganglion neurons of these afferents. In the present study, we report the novel finding that insulin augments the mechanical responsiveness of thin fibre afferents not only at dorsal root ganglion, but also at muscle tissue levels. Our data suggest that sympathoexcitation is mediated via the insulin-induced mechanical sensitization peripherally. The present study proposes a novel physiological role of insulin in the regulation of mechanical sensitivity in somatosensory thin fibre afferents. ABSTRACT Insulin activates the sympathetic nervous system, although the mechanism underlying insulin-induced sympathoexcitation remains to be determined. A mechanical stimulus to tissues such as skin and/or skeletal muscle, no matter whether the stimulation is noxious or not, activates the sympathetic nervous system via thin fibre afferents. Evidence suggests that insulin modulates putative mechanosensitive channels in the dorsal root ganglion (DRG) neurons of these afferents. Accordingly, we investigated whether insulin augments whole-cell current responses to mechanical stimuli in small DRG neurons of normal healthy mice. We performed whole-cell patch clamp recordings using cultured DRG neurons and observed mechanically-activated (MA) currents induced by mechanical stimuli applied to the cell surface. Local application of vehicle solution did not change MA currents or mechanical threshold in cultured DRG neurons. Insulin (500 mU mL-1 ) significantly augmented the amplitude of MA currents (P < 0.05) and decreased the mechanical threshold (P < 0.05). Importantly, pretreatment with the insulin receptor antagonist, GSK1838705, significantly suppressed the insulin-induced potentiation of the mechanical response. We further examined the impact of insulin on thin fibre muscle afferent activity in response to mechanical stimuli in normal healthy rats in vitro. Using a muscle-nerve preparation, we recorded single group IV fibre activity to a ramp-shaped mechanical stimulation. Insulin significantly decreased mechanical threshold (P < 0.05), although it did not significantly increase the response magnitude to the mechanical stimulus. In conclusion, these data suggest that insulin augments the mechanical responsiveness of small DRG neurons and potentially sensitizes group IV afferents to mechanical stimuli at the muscle tissue level, possibly contributing to insulin-induced sympathoexcitation.
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Affiliation(s)
- Norio Hotta
- College of Life and Health Sciences, Chubu University, Kasugai, Japan.,Departments of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Kazue Mizumura
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Gary A Iwamoto
- Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Rie Ishizawa
- Departments of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Han-Kyul Kim
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Wanpen Vongpatanasin
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jere H Mitchell
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Scott A Smith
- Departments of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Masaki Mizuno
- Departments of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
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11
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Sheehan K, Lee J, Chong J, Zavala K, Sharma M, Philipsen S, Maruyama T, Xu Z, Guan Z, Eilers H, Kawamata T, Schumacher M. Transcription factor Sp4 is required for hyperalgesic state persistence. PLoS One 2019; 14:e0211349. [PMID: 30811405 PMCID: PMC6392229 DOI: 10.1371/journal.pone.0211349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/11/2019] [Indexed: 12/14/2022] Open
Abstract
Understanding how painful hypersensitive states develop and persist beyond the initial hours to days is critically important in the effort to devise strategies to prevent and/or reverse chronic painful states. Changes in nociceptor transcription can alter the abundance of nociceptive signaling elements, resulting in longer-term change in nociceptor phenotype. As a result, sensitized nociceptive signaling can be further amplified and nocifensive behaviors sustained for weeks to months. Building on our previous finding that transcription factor Sp4 positively regulates the expression of the pain transducing channel TRPV1 in Dorsal Root Ganglion (DRG) neurons, we sought to determine if Sp4 serves a broader role in the development and persistence of hypersensitive states in mice. We observed that more than 90% of Sp4 staining DRG neurons were small to medium sized, primarily unmyelinated (NF200 neg) and the majority co-expressed nociceptor markers TRPV1 and/or isolectin B4 (IB4). Genetically modified mice (Sp4+/-) with a 50% reduction of Sp4 showed a reduction in DRG TRPV1 mRNA and neuronal responses to the TRPV1 agonist-capsaicin. Importantly, Sp4+/- mice failed to develop persistent inflammatory thermal hyperalgesia, showing a reversal to control values after 6 hours. Despite a reversal of inflammatory thermal hyperalgesia, there was no difference in CFA-induced hindpaw swelling between CFA Sp4+/- and CFA wild type mice. Similarly, Sp4+/- mice failed to develop persistent mechanical hypersensitivity to hind-paw injection of NGF. Although Sp4+/- mice developed hypersensitivity to traumatic nerve injury, Sp4+/- mice failed to develop persistent cold or mechanical hypersensitivity to the platinum-based chemotherapeutic agent oxaliplatin, a non-traumatic model of neuropathic pain. Overall, Sp4+/- mice displayed a remarkable ability to reverse the development of multiple models of persistent inflammatory and neuropathic hypersensitivity. This suggests that Sp4 functions as a critical control point for a network of genes that conspire in the persistence of painful hypersensitive states.
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Affiliation(s)
- Kayla Sheehan
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Jessica Lee
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Jillian Chong
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Kathryn Zavala
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Manohar Sharma
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Sjaak Philipsen
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Tomoyuki Maruyama
- Department of Anesthesiology, Wakayama Medical University, Wakayama, Japan
| | - Zheyun Xu
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Zhonghui Guan
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Helge Eilers
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Tomoyuki Kawamata
- Department of Anesthesiology, Wakayama Medical University, Wakayama, Japan
| | - Mark Schumacher
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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12
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Lázár BA, Jancsó G, Pálvölgyi L, Dobos I, Nagy I, Sántha P. Insulin Confers Differing Effects on Neurite Outgrowth in Separate Populations of Cultured Dorsal Root Ganglion Neurons: The Role of the Insulin Receptor. Front Neurosci 2018; 12:732. [PMID: 30364236 PMCID: PMC6191510 DOI: 10.3389/fnins.2018.00732] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 09/24/2018] [Indexed: 01/04/2023] Open
Abstract
Apart from its pivotal role in the regulation of carbohydrate metabolism, insulin exerts important neurotrophic and neuromodulator effects on dorsal root ganglion (DRG) neurons. The neurite outgrowth-promoting effect is one of the salient features of insulin's action on cultured DRG neurons. Although it has been established that a significant population of DRG neurons express the insulin receptor (InsR), the significance of InsR expression and the chemical phenotype of DRG neurons in relation to the neurite outgrowth-promoting effect of insulin has not been studied. Therefore, in this study by using immunohistochemical and quantitative stereological methods we evaluated the effect of insulin on neurite outgrowth of DRG neurons of different chemical phenotypes which express or lack the InsR. Insulin, at a concentration of 10 nM, significantly increased total neurite length, the length of the longest neurite and the number of branch points of cultured DRG neurons as compared to neurons cultured in control medium or in the presence of 1 μM insulin. In both the control and the insulin exposed cultures, ∼43% of neurons displayed InsR-immunoreactivity. The proportions of transient receptor potential vanilloid type 1 receptor (TRPV1)-immunoreactive (IR), calcitonin gene-related peptide (CGRP)-IR and Bandeiraea simplicifolia isolectin B4 (IB4)-binding neurons amounted to ∼61%, ∼57%, and ∼31% of DRG neurons IR for the InsR. Of the IB4-positive population only neurons expressing the InsR were responsive to insulin. In contrast, TRPV1-IR nociceptive and CGRP-IR peptidergic neurons showed increased tendency for neurite outgrowth which was further enhanced by insulin. However, the responsiveness of DRG neurons expressing the InsR was superior to populations of DRG neurons which lack this receptor. The findings also revealed that besides the expression of the InsR, inherent properties of peptidergic, but not non-peptidergic nociceptive neurons may also significantly contribute to the mechanisms of neurite outgrowth of DRG neurons. These observations suggest distinct regenerative propensity for differing populations of DRG neurons which is significantly affected through insulin receptor signaling.
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Affiliation(s)
- Bence András Lázár
- Department of Psychiatry, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Physiology, University of Szeged, Szeged, Hungary
| | - Gábor Jancsó
- Department of Physiology, University of Szeged, Szeged, Hungary
| | - Laura Pálvölgyi
- Department of Physiology, University of Szeged, Szeged, Hungary
| | - Ildikó Dobos
- Department of Physiology, University of Szeged, Szeged, Hungary
| | - István Nagy
- Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Péter Sántha
- Department of Physiology, University of Szeged, Szeged, Hungary
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13
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Lázár BA, Jancsó G, Nagy I, Horváth V, Sántha P. The insulin receptor is differentially expressed in somatic and visceral primary sensory neurons. Cell Tissue Res 2018; 374:243-249. [PMID: 29955950 DOI: 10.1007/s00441-018-2868-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 06/04/2018] [Indexed: 10/28/2022]
Abstract
Recent studies demonstrated the expression of the insulin receptor (InsR) and its functional interaction with the transient receptor potential vanilloid type 1 receptor (TRPV1) in primary sensory neurons (PSNs). The present study was undertaken to reveal the target-specific expression of the InsR and its co-localization with the TRPV1 in rat PSNs. We assessed the localization of the InsR and its co-localization with the TRPV1 in PSNs retrogradely labelled with biotin-conjugated wheat germ agglutinin injected into the dorsal hind paw skin, the gastrocnemius muscle, the pancreas and the urinary bladder wall. The largest proportions of retrogradely labelled InsR-immunoreactive neurons were identified among PSNs serving the pancreas (~ 54%) and the urinary bladder (~ 53%). The proportions of retrogradely labelled InsR-immunoreactive neurons innervating the dorsal hind paw skin and the gastrocnemius muscle amounted to ~ 22 and ~ 21%. TRPV1-immunoreactive neurons amounted to ~ 63, ~ 62, ~ 67 and ~ 65% of retrogradely labelled cutaneous, muscle, pancreatic and urinary bladder PSNs, respectively. Co-localization of the TRPV1 with the InsR was observed in ~ 16, ~ 15, ~ 29 and ~ 30% of retrogradely labelled cutaneous, muscle, pancreatic and urinary bladder PSNs. These quantitative immunohistochemical data demonstrate a preponderance of InsR-immunoreactivity among PSNs, which innervate visceral targets. The present findings suggest that visceral spinal PSNs are more likely to be exposed to the modulatory effects of insulin on sensory functions, including neurotrophic, nociceptive and inflammatory processes.
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Affiliation(s)
- Bence András Lázár
- Department of Psychiatry, University of Szeged, Kálvária sugárút 57, Szeged, H-6725, Hungary. .,Department of Physiology, University of Szeged, Szeged, Hungary.
| | - Gábor Jancsó
- Department of Physiology, University of Szeged, Szeged, Hungary
| | - István Nagy
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Viktor Horváth
- First Department of Internal Medicine, Semmelweis University, Budapest, Hungary
| | - Péter Sántha
- Department of Physiology, University of Szeged, Szeged, Hungary
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14
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The Insulin Receptor Is Colocalized With the TRPV1 Nociceptive Ion Channel and Neuropeptides in Pancreatic Spinal and Vagal Primary Sensory Neurons. Pancreas 2018; 47:110-115. [PMID: 29215540 DOI: 10.1097/mpa.0000000000000959] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES Recent observations demonstrated the expression of the insulin receptor (InsR) and its functional interaction with the transient receptor potential vanilloid type 1 receptor (TRPV1) in sensory ganglion neurons. Because sensory nerves are implicated in pancreatic inflammatory processes, we studied the colocalization of the InsR with TRPV1 and proinflammatory neuropeptides in spinal and vagal pancreatic afferent neurons. METHODS Immunohistochemistry and quantitative morphometry were used to analyze the expression of TRPV1, InsR, substance P (SP), and calcitonin gene-related peptide (CGRP) in retrogradely labeled pancreatic dorsal root ganglion (DRG) and nodose ganglion (NG) neurons. RESULTS The proportions of retrogradely labeled pancreatic TRPV1-, InsR-, SP-, and CGRP-immunoreactive neurons amounted to 68%, 48%, 33%, and 54% in DRGs and 64%, 49%, 40%, and 25% in the NGs. Of the labeled DRG and NG neurons, 23% and 35% showed both TRPV1 and InsR immunoreactivity. Colocalization of the InsR with SP or CGRP was demonstrated in 14% and 28% of pancreatic DRG and 24% and 8% of pancreatic NG neurons. CONCLUSIONS The present findings provide morphological basis for possible functional interactions among the nociceptive ion channel TRPV1, the InsR, and the proinflammatory neuropeptides SP and CGRP expressed by pancreatic DRG and NG neurons.
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15
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Ritter KE, Southard-Smith EM. Dynamic Expression of Serotonin Receptor 5-HT3A in Developing Sensory Innervation of the Lower Urinary Tract. Front Neurosci 2017; 10:592. [PMID: 28111539 PMCID: PMC5216032 DOI: 10.3389/fnins.2016.00592] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/12/2016] [Indexed: 12/12/2022] Open
Abstract
Sensory afferent signaling is required for normal function of the lower urinary tract (LUT). Despite the wide prevalence of bladder dysfunction and pelvic pain syndromes, few effective treatment options are available. Serotonin receptor 5-HT3A is a known mediator of visceral afferent signaling and has been implicated in bladder function. However, basic expression patterns for this gene and others among developing bladder sensory afferents that could be used to inform regenerative efforts aimed at treating deficiencies in pelvic innervation are lacking. To gain greater insight into the molecular characteristics of bladder sensory innervation, we conducted a thorough characterization of Htr3a expression in developing and adult bladder-projecting lumbosacral dorsal root ganglia (DRG) neurons. Using a transgenic Htr3a-EGFP reporter mouse line, we identified 5-HT3A expression at 10 days post coitus (dpc) in neural crest derivatives and in 12 dpc lumbosacral DRG. Using immunohistochemical co-localization we observed Htr3a-EGFP expression in developing lumbosacral DRG that partially coincides with neuropeptides CGRP and Substance P and capsaicin receptor TRPV1. A majority of Htr3a-EGFP+ DRG neurons also express a marker of myelinated Aδ neurons, NF200. There was no co-localization of 5-HT3A with the TRPV4 receptor. We employed retrograde tracing in adult Htr3a-EGFP mice to quantify the contribution of 5-HT3A+ DRG neurons to bladder afferent innervation. We found that 5-HT3A is expressed in a substantial proportion of retrograde traced DRG neurons in both rostral (L1, L2) and caudal (L6, S1) axial levels that supply bladder innervation. Most bladder-projecting Htr3a-EGFP+ neurons that co-express CGRP, Substance P, or TRPV1 are found in L1, L2 DRG, whereas Htr3a-EGFP+, NF200+ bladder-projecting neurons are from the L6, S1 axial levels. Our findings contribute much needed information regarding the development of LUT innervation and highlight the 5-HT3A serotonin receptor as a candidate for future studies of neurally mediated bladder control.
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Affiliation(s)
- K Elaine Ritter
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University School of Medicine Nashville, TN, USA
| | - E Michelle Southard-Smith
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University School of Medicine Nashville, TN, USA
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16
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Grote CW, Wright DE. A Role for Insulin in Diabetic Neuropathy. Front Neurosci 2016; 10:581. [PMID: 28066166 PMCID: PMC5179551 DOI: 10.3389/fnins.2016.00581] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 12/06/2016] [Indexed: 12/13/2022] Open
Abstract
The peripheral nervous system is one of several organ systems that are profoundly affected in diabetes. The longstanding view is that insulin does not have a major role in modulating neuronal function in both central and peripheral nervous systems is now being challenged. In the setting of insulin deficiency or excess insulin, it is logical to propose that insulin dysregulation can contribute to neuropathic changes in sensory neurons. This is particularly important as sensory nerve damage associated with prediabetes, type 1 and type 2 diabetes is so prevalent. Here, we discuss the current experimental literature related to insulin's role as a potential neurotrophic factor in peripheral nerve function, as well as the possibility that insulin deficiency plays a role in diabetic neuropathy. In addition, we discuss how sensory neurons in the peripheral nervous system respond to insulin similar to other insulin-sensitive tissues. Moreover, studies now suggest that sensory neurons can also become insulin resistant like other tissues. Collectively, emerging studies are revealing that insulin signaling pathways are active contributors to sensory nerve modulation, and this review highlights this novel activity and should provide new insight into insulin's role in both peripheral and central nervous system diseases.
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Affiliation(s)
- Caleb W Grote
- Department of Anatomy and Cell Biology, University of Kansas Medical Center Kansas City, KS, USA
| | - Douglas E Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center Kansas City, KS, USA
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17
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Chen J, Varga A, Selvarajah S, Jenes A, Dienes B, Sousa-Valente J, Kulik A, Veress G, Brain SD, Baker D, Urban L, Mackie K, Nagy I. Spatial Distribution of the Cannabinoid Type 1 and Capsaicin Receptors May Contribute to the Complexity of Their Crosstalk. Sci Rep 2016; 6:33307. [PMID: 27653550 PMCID: PMC5032030 DOI: 10.1038/srep33307] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/24/2016] [Indexed: 01/07/2023] Open
Abstract
The cannabinoid type 1 (CB1) receptor and the capsaicin receptor (TRPV1) exhibit co-expression and complex, but largely unknown, functional interactions in a sub-population of primary sensory neurons (PSN). We report that PSN co-expressing CB1 receptor and TRPV1 form two distinct sub-populations based on their pharmacological properties, which could be due to the distribution pattern of the two receptors. Pharmacologically, neurons respond either only to capsaicin (COR neurons) or to both capsaicin and the endogenous TRPV1 and CB1 receptor ligand anandamide (ACR neurons). Blocking or deleting the CB1 receptor only reduces both anandamide- and capsaicin-evoked responses in ACR neurons. Deleting the CB1 receptor also reduces the proportion of ACR neurons without any effect on the overall number of capsaicin-responding cells. Regarding the distribution pattern of the two receptors, neurons express CB1 and TRPV1 receptors either isolated in low densities or in close proximity with medium/high densities. We suggest that spatial distribution of the CB1 receptor and TRPV1 contributes to the complexity of their functional interaction.
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Affiliation(s)
- Jie Chen
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK.,Department of Anaesthesiology, Southwest Hospital, Third Military Medical University, Gaotanyan 19 Street, Shapingba, Chongqing 400038, P. R. China
| | - Angelika Varga
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK.,MTA-DE-NAP B-Pain Control Research GroupDepartment of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, Debrecen, H-4012, Hungary
| | - Srikumaran Selvarajah
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK
| | - Agnes Jenes
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK.,MTA-DE-NAP B-Pain Control Research GroupDepartment of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, Debrecen, H-4012, Hungary
| | - Beatrix Dienes
- MTA-DE-NAP B-Pain Control Research GroupDepartment of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, Debrecen, H-4012, Hungary
| | - Joao Sousa-Valente
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK
| | - Akos Kulik
- Institute of Physiology, University of Freiburg, Germany D-79104 Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104, Germany
| | - Gabor Veress
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Susan D Brain
- BHF Cardiovascular Centre of Excellence and Centre of Integrative Biomedicine, Cardiovascular Division, King's College London, London SE1 9NH, UK
| | - David Baker
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London, E1 2AT, UK
| | - Laszlo Urban
- Preclinical Secondary Pharmacology, Preclinical Safety, Novartis Institutes for Biommedical Research, Cambridge, MA 01932, USA
| | - Ken Mackie
- Department of Psychological and Brain Sciences and Program in Neuroscience, Indiana University, The Gill Center, 702 N. Walnut Grove Avenue, Bloomington, IN 47405, USA
| | - Istvan Nagy
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK
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18
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Sango K, Utsunomiya K. Efficacy of glucagon-like peptide-1 mimetics for neural regeneration. Neural Regen Res 2016; 10:1723-4. [PMID: 26807090 PMCID: PMC4705767 DOI: 10.4103/1673-5374.169611] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Kazunori Sango
- Diabetic Neuropathy Project (Former ALS/Neuropathy project), Department of Sensory and Motor Systems, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Kazunori Utsunomiya
- Division of Diabetes, Metabolism & Endocrinology, Department of Internal Medicine, Jikei University School of Medicine, Minato-ku, Tokyo, Japan
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19
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Tsukamoto M, Niimi N, Sango K, Takaku S, Kanazawa Y, Utsunomiya K. Neurotrophic and neuroprotective properties of exendin-4 in adult rat dorsal root ganglion neurons: involvement of insulin and RhoA. Histochem Cell Biol 2015; 144:249-59. [PMID: 26026990 DOI: 10.1007/s00418-015-1333-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2015] [Indexed: 11/26/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is thought to preserve neurons and glia following axonal injury and neurodegenerative disorders. We investigated the neurotrophic and neuroprotective properties of exendin (Ex)-4, a synthetic GLP-1 receptor (GLP-1R) agonist, on adult rat dorsal root ganglion (DRG) neurons and PC12 cells. GLP-1R was predominantly localized on large and small peptidergic neurons in vivo and in vitro, suggesting the involvement of GLP-1 in both the large and small sensory fiber functions. Ex-4 dose-dependently (1 ≤ 10 ≤ 100 nM) promoted neurite outgrowth and neuronal survival at 2 and 7 days in culture, respectively. Treatment with 100 nM Ex-4 restored the reduced neurite outgrowth and viability of DRG neurons caused by the insulin removal from the medium and suppressed the activity of RhoA, an inhibitory regulator for peripheral nerve regeneration, in PC12 cells. Furthermore, these effects were attenuated by co-treatment with phosphatidylinositol-3'-phosphate kinase (PI3K) inhibitor, LY294002. These findings imply that Ex-4 enhances neurite outgrowth and neuronal survival through the activation of PI3K signaling pathway, which negatively regulates RhoA activity. Ex-4 and other GLP-1R agonists may compensate for the reduced insulin effects on neurons, thereby being beneficial for the treatment of diabetic neuropathy.
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Affiliation(s)
- Masami Tsukamoto
- Diabetic Neuropathy Project (Former Laboratory of Peripheral Nerve Pathophysiology), Department of Sensory and Motor Systems, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
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20
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Bae JY, Kim JH, Cho YS, Mah W, Bae YC. Quantitative analysis of afferents expressing substance P, calcitonin gene-related peptide, isolectin B4, neurofilament 200, and Peripherin in the sensory root of the rat trigeminal ganglion. J Comp Neurol 2014; 523:126-38. [DOI: 10.1002/cne.23672] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/21/2014] [Accepted: 08/25/2014] [Indexed: 12/19/2022]
Affiliation(s)
- Jin Young Bae
- Department of Anatomy and Neurobiology; School of Dentistry, Kyungpook National University; Daegu 700-412 South Korea
| | - Jae Hyun Kim
- Department of Anatomy and Neurobiology; School of Dentistry, Kyungpook National University; Daegu 700-412 South Korea
| | - Yi Sul Cho
- Department of Anatomy and Neurobiology; School of Dentistry, Kyungpook National University; Daegu 700-412 South Korea
| | - Won Mah
- Department of Anatomy and Neurobiology; School of Dentistry, Kyungpook National University; Daegu 700-412 South Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology; School of Dentistry, Kyungpook National University; Daegu 700-412 South Korea
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21
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Activation of CB1 inhibits NGF-induced sensitization of TRPV1 in adult mouse afferent neurons. Neuroscience 2014; 277:679-89. [PMID: 25088915 DOI: 10.1016/j.neuroscience.2014.07.041] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 06/12/2014] [Accepted: 07/02/2014] [Indexed: 01/02/2023]
Abstract
Transient receptor potential vanilloid 1 (TRPV1)-containing afferent neurons convey nociceptive signals and play an essential role in pain sensation. Exposure to nerve growth factor (NGF) rapidly increases TRPV1 activity (sensitization). In the present study, we investigated whether treatment with the selective cannabinoid receptor 1 (CB1) agonist arachidonyl-2'-chloroethylamide (ACEA) affects NGF-induced sensitization of TRPV1 in adult mouse dorsal root ganglion (DRG) afferent neurons. We found that CB1, NGF receptor tyrosine kinase A (trkA), and TRPV1 are present in cultured adult mouse small- to medium-sized afferent neurons and treatment with NGF (100ng/ml) for 30 min significantly increased the number of neurons that responded to capsaicin (as indicated by increased intracellular Ca(2 +) concentration). Pretreatment with the CB1 agonist ACEA (10nM) inhibited the NGF-induced response, and this effect of ACEA was reversed by a selective CB1 antagonist. Further, pretreatment with ACEA inhibited NGF-induced phosphorylation of AKT. Blocking PI3 kinase activity also attenuated the NGF-induced increase in the number of neurons that responded to capsaicin. Our results indicate that the analgesic effect of CB1 activation may in part be due to inhibition of NGF-induced sensitization of TRPV1 and also that the effect of CB1 activation is at least partly mediated by attenuation of NGF-induced increased PI3 signaling.
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22
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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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23
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Brandao KE, Dell'Acqua ML, Levinson SR. A-kinase anchoring protein 150 expression in a specific subset of TRPV1- and CaV 1.2-positive nociceptive rat dorsal root ganglion neurons. J Comp Neurol 2012; 520:81-99. [PMID: 21674494 PMCID: PMC4807902 DOI: 10.1002/cne.22692] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Modulation of phosphorylation states of ion channels is a critical step in the development of hyperalgesia during inflammation. Modulatory enhancement of channel activity may increase neuronal excitability and affect downstream targets such as gene transcription. The specificity required for such regulation of ion channels quickly occurs via targeting of protein kinases and phosphatases by the scaffolding A-kinase anchoring protein 79/150 (AKAP79/150). AKAP79/150 has been implicated in inflammatory pain by targeting protein kinase A (PKA) and protein kinase C (PKC) to the transient receptor potential vanilloid 1 (TRPV1) channel in peripheral sensory neurons, thus lowering threshold for activation of the channel by multiple inflammatory reagents. However, the expression pattern of AKAP150 in peripheral sensory neurons is unknown. Here we identify the peripheral neuron subtypes that express AKAP150, the subcellular distribution of AKAP150, and the potential target ion channels in rat dorsal root ganglion (DRG) slices. We found that AKAP150 is expressed predominantly in a subset of small DRG sensory neurons, where it is localized at the plasma membrane of the soma, axon initial segment, and small fibers. Most of these neurons are peripherin positive and produce C fibers, although a small portion produce Aδ fibers. Furthermore, we demonstrate that AKAP79/150 colocalizes with TRPV1 and Ca(V) 1.2 in the soma and axon initial segment. Thus AKAP150 is expressed in small, nociceptive DRG neurons, where it is targeted to membrane regions and where it may play a role in the modulation of ion channel phosphorylation states required for hyperalgesia.
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Affiliation(s)
- Katherine E Brandao
- Program in Neuroscience, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA
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Insulin receptor substrate 2 expression and involvement in neuronal insulin resistance in diabetic neuropathy. EXPERIMENTAL DIABETES RESEARCH 2011; 2011:212571. [PMID: 21754917 PMCID: PMC3132877 DOI: 10.1155/2011/212571] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 03/22/2011] [Accepted: 04/15/2011] [Indexed: 12/11/2022]
Abstract
Insulin signaling depends on tyrosine phosphorylation of insulin receptor substrates (IRSs) to mediate downstream effects; however, elevated serine phosphorylation of IRS impairs insulin signaling. Here, we investigated IRS protein expression patterns in dorsal root ganglia (DRG) of mice and whether their signaling was affected by diabetes. Both IRS1 and IRS2 are expressed in DRG; however, IRS2 appears to be the prevalent isoform and is expressed by many DRG neuronal subtypes. Phosphorylation of Ser(731)IRS2 was significantly elevated in DRG neurons from type 1 and type 2 diabetic mice. Additionally, Akt activation and neurite outgrowth in response to insulin were significantly decreased in DRG cultures from diabetic ob/ob mice. These results suggest that DRG neurons express IRS proteins that are altered by diabetes similar to other peripheral tissues, and insulin signaling downstream of the insulin receptor may be impaired in sensory neurons and contribute to the pathogenesis of diabetic neuropathy.
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Hartmann P, Varga R, Zobolyák Z, Héger J, Csősz B, Németh I, Rázga Z, Vízler C, Garab D, Sántha P, Jancsó G, Boros M, Szabó A. Anti-inflammatory effects of limb ischaemic preconditioning are mediated by sensory nerve activation in rats. Naunyn Schmiedebergs Arch Pharmacol 2010; 383:179-89. [DOI: 10.1007/s00210-010-0588-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 12/07/2010] [Indexed: 01/27/2023]
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Fujita M, Andoh T, Sasaki A, Saiki I, Kuraishi Y. Involvement of peripheral adenosine 5'-triphosphate and P2X purinoceptor in pain-related behavior produced by orthotopic melanoma inoculation in mice. Eur J Neurosci 2010; 31:1629-36. [PMID: 20525075 DOI: 10.1111/j.1460-9568.2010.07185.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Adenosine 5'-triphosphate (ATP) plays an important role in nociceptive processing. We used a mouse model of skin cancer pain to investigate the role of ATP in cancer pain. Orthotopic inoculation of B16-BL6 melanoma cells into the hind paw produced spontaneous licking of the tumor-bearing paw. Intraperitoneal injection of the P2 purinoceptor antagonist suramin suppressed spontaneous licking dose-dependently. Two P2X purinoceptor antagonists also suppressed spontaneous licking. An intraplantar injection of ATP, which did not induce licking in the healthy paw, increased licking of the tumor-bearing paw. Spontaneous firing of the tibial nerve was significantly increased in tumor-bearing mice and was inhibited by suramin. Extracellular concentration of ATP was significantly increased in the tumor-bearing paw than in the normal paw. ATP is concentrated in the culture medium of melanoma, lung cancer and breast cancer cells, but not fibroblasts. The P2X(3) receptor was expressed in about 40% of peripherin-positive small and medium-sized neurons in the dorsal root ganglia. P2X(3)-positive neurons were significantly increased in melanoma-bearing mice. These results suggest that ATP and P2X, especially P2X(3), receptors are involved in skin cancer pain, due to the increased release of ATP and increased expression of P2X(3) receptors in the sensory neurons.
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Affiliation(s)
- Masahide Fujita
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama, Japan
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Vulchanova L, Schuster DJ, Belur LR, Riedl MS, Podetz-Pedersen KM, Kitto KF, Wilcox GL, McIvor RS, Fairbanks CA. Differential adeno-associated virus mediated gene transfer to sensory neurons following intrathecal delivery by direct lumbar puncture. Mol Pain 2010; 6:31. [PMID: 20509925 PMCID: PMC2900238 DOI: 10.1186/1744-8069-6-31] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 05/28/2010] [Indexed: 12/31/2022] Open
Abstract
Background Neuronal transduction by adeno-associated viral (AAV) vectors has been demonstrated in cortex, brainstem, cerebellum, and sensory ganglia. Intrathecal delivery of AAV serotypes that transduce neurons in dorsal root ganglia (DRG) and spinal cord offers substantial opportunities to 1) further study mechanisms underlying chronic pain, and 2) develop novel gene-based therapies for the treatment and management of chronic pain using a non-invasive delivery route with established safety margins. In this study we have compared expression patterns of AAV serotype 5 (AAV5)- and AAV serotype 8 (AAV8)-mediated gene transfer to sensory neurons following intrathecal delivery by direct lumbar puncture. Results Intravenous mannitol pre-treatment significantly enhanced transduction of primary sensory neurons after direct lumbar puncture injection of AAV5 (rAAV5-GFP) or AAV8 (rAAV8-GFP) carrying the green fluorescent protein (GFP) gene. The presence of GFP in DRG neurons was consistent with the following evidence for primary afferent origin of the majority of GFP-positive fibers in spinal cord: 1) GFP-positive axons were evident in both dorsal roots and dorsal columns; and 2) dorsal rhizotomy, which severs the primary afferent input to spinal cord, abolished the majority of GFP labeling in dorsal horn. We found that both rAAV5-GFP and rAAV8-GFP appear to preferentially target large-diameter DRG neurons, while excluding the isolectin-B4 (IB4) -binding population of small diameter neurons. In addition, a larger proportion of CGRP-positive cells was transduced by rAAV5-GFP, compared to rAAV8-GFP. Conclusions The present study demonstrates the feasibility of minimally invasive gene transfer to sensory neurons using direct lumbar puncture and provides evidence for differential targeting of subtypes of DRG neurons by AAV vectors.
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Affiliation(s)
- Lucy Vulchanova
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
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Spicarova D, Palecek J. Modulation of AMPA excitatory postsynaptic currents in the spinal cord dorsal horn neurons by insulin. Neuroscience 2009; 166:305-11. [PMID: 20005924 DOI: 10.1016/j.neuroscience.2009.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 11/16/2009] [Accepted: 12/02/2009] [Indexed: 11/17/2022]
Abstract
Glutamate AMPA receptors are critical for sensory transmission at the spinal cord dorsal horn (DH). Plasma membrane AMPA receptor endocytosis that can be induced by insulin may underlie long term modulation of synaptic transmission. Insulin receptors (IRs) are known to be expressed on spinal cord DH neurons, but their possible role in sensory transmission has not been studied. In this work the effect of insulin application on fast excitatory postsynaptic currents (EPSCs) mediated by AMPA receptors evoked in DH neurons was evaluated. Acute spinal cord slices from 6 to 10 day old mice were used to record EPSCs evoked in visually identified superficial DH neurons by dorsal root primary afferent stimulation. AMPA EPSCs could be evoked in all of the tested neurons. In 75% of the neurons the size of the AMPA EPSCs was reduced to 62.1% and to 68.9% of the control values when 0.5 or 10 microM insulin was applied. There was no significant change in the size of the AMPA EPSCs in the remaining 25% of DH neurons. The membrane permeable protein tyrosine kinase inhibitor, lavendustin A (10 microM), prevented the insulin induced AMPA EPSC depression. Our results suggest a possible role of the insulin pathway in modulation of sensory and nociceptive synaptic transmission in the spinal cord.
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Affiliation(s)
- D Spicarova
- Department of Functional Morphology, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
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Amadesi S, Grant AD, Cottrell GS, Vaksman N, Poole DP, Rozengurt E, Bunnett NW. Protein kinase D isoforms are expressed in rat and mouse primary sensory neurons and are activated by agonists of protease-activated receptor 2. J Comp Neurol 2009; 516:141-56. [PMID: 19575452 DOI: 10.1002/cne.22104] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Serine proteases generated during injury and inflammation cleave protease-activated receptor 2 (PAR(2)) on primary sensory neurons to induce neurogenic inflammation and hyperalgesia. Hyperalgesia requires sensitization of transient receptor potential vanilloid (TRPV) ion channels by mechanisms involving phospholipase C and protein kinase C (PKC). The protein kinase D (PKD) serine/threonine kinases are activated by diacylglycerol and PKCs and can phosphorylate TRPV1. Thus, PKDs may participate in novel signal transduction pathways triggered by serine proteases during inflammation and pain. However, it is not known whether PAR(2) activates PKD, and the expression of PKD isoforms by nociceptive neurons is poorly characterized. By using HEK293 cells transfected with PKDs, we found that PAR(2) stimulation promoted plasma membrane translocation and phosphorylation of PKD1, PKD2, and PKD3, indicating activation. This effect was partially dependent on PKCepsilon. By immunofluorescence and confocal microscopy, with antibodies against PKD1/PKD2 and PKD3 and neuronal markers, we found that PKDs were expressed in rat and mouse dorsal root ganglia (DRG) neurons, including nociceptive neurons that expressed TRPV1, PAR(2), and neuropeptides. PAR(2) agonist induced phosphorylation of PKD in cultured DRG neurons, indicating PKD activation. Intraplantar injection of PAR(2) agonist also caused phosphorylation of PKD in neurons of lumbar DRG, confirming activation in vivo. Thus, PKD1, PKD2, and PKD3 are expressed in primary sensory neurons that mediate neurogenic inflammation and pain transmission, and PAR(2) agonists activate PKDs in HEK293 cells and DRG neurons in culture and in intact animals. PKD may be a novel component of a signal transduction pathway for protease-induced activation of nociceptive neurons and an important new target for antiinflammatory and analgesic therapies.
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Affiliation(s)
- Silvia Amadesi
- Center for Neurobiology of Digestive Diseases, University of California, San Francisco, San Francisco, California 94143-0660, USA
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Ishida Y, Ugawa S, Ueda T, Yamada T, Shibata Y, Hondoh A, Inoue K, Yu Y, Shimada S. P2X(2)- and P2X(3)-positive fibers in fungiform papillae originate from the chorda tympani but not the trigeminal nerve in rats and mice. J Comp Neurol 2009; 514:131-44. [PMID: 19266560 DOI: 10.1002/cne.22000] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The subtype 2 and subtype 3 ionotropic purinergic receptors (P2X receptors) are crucial for gustation, but the distribution of these receptors in the geniculate ganglion (GG) and their colocalization in tongue papillae remain unknown. Here we investigated the expression and colocalization of P2X(2) and P2X(3) receptors in the GG and fungiform papillae in rats and mice by using in situ hybridization and immunohistochemistry. In both species, P2X(2) transcripts and immunoreactivity were detected in approximately 50-60% of GG neuronal somata, whereas those of P2X(3) were observed in almost all neurons. In each fungiform papilla, immunoreactivity for both receptors was mostly colocalized and was seen in nerve fibers and their bundles concentrated in the taste buds. Because it is well known that the P2X receptors are involved in not only taste but also nociception, we determined whether the expression originated from the chorda tympani nerve (CT, gustatory) or trigeminal nerve (somatosensory) by cutting the CT in both animals. Most P2X(2) and P2X(3) immunoreactivity in the fungiform papillae was abolished after transection, although the nerve fiber immunoreactivity of transient receptor potential V1 (a marker of somatosensory nerve fibers) remained unchanged, indicating that most fungiform papillae nerve fibers with P2X(2) and P2X(3) receptors were derived from CT. Taken together, these findings suggest that most P2X(2) and P2X(3) receptors in fungiform papillae are used for gustation rather than somatosensation.
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Affiliation(s)
- Yusuke Ishida
- Department of Neurobiology and Anatomy, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
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GRC-6211, a New Oral Specific TRPV1 Antagonist, Decreases Bladder Overactivity and Noxious Bladder Input in Cystitis Animal Models. J Urol 2009; 181:379-86. [DOI: 10.1016/j.juro.2008.08.121] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Indexed: 11/23/2022]
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Buniel M, Glazebrook PA, Ramirez-Navarro A, Kunze DL. Distribution of voltage-gated potassium and hyperpolarization-activated channels in sensory afferent fibers in the rat carotid body. J Comp Neurol 2008; 510:367-77. [PMID: 18668683 DOI: 10.1002/cne.21796] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The chemosensory glomus cells of the carotid body (CB) detect changes in O2 tension. Carotid sinus nerve fibers, which originate from peripheral sensory neurons located within the petrosal ganglion, innervate the CB. Release of transmitter from glomus cells activates the sensory afferent fibers to transmit information to the nucleus of the solitary tract in the brainstem. The ion channels expressed within the sensory nerve terminals play an essential role in the ability of the terminal to initiate action potentials in response to transmitter-evoked depolarization. However, with a few exceptions, the identity of ion channels expressed in these peripheral nerve fibers is unknown. This study addresses the expression of voltage-gated channels in the sensory fibers with a focus on channels that set the resting membrane potential and regulate discharge patterns. By using immunohistochemistry and fluorescence confocal microscopy, potassium channel subunits and HCN (hyperpolarization-activated) family members were localized both in petrosal neurons that expressed tyrosine hydroxylase and in the CSN axons within the carotid body. Channels contributing to resting membrane potential, including HCN2 responsible in part for I(h) current and the KCNQ2 and KCNQ5 subunits thought to underlie the neuronal "M current," were identified in the sensory neurons and their axons innervating the carotid body. In addition, the results presented here demonstrate expression of several potassium channels that shape the action potential and the frequency of discharge, including Kv1.4, Kv1.5, Kv4.3, and K(Ca) (BK). The role of these channels should be considered in interpretation of the fiber discharge in response to perturbation of the carotid body environment.
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Affiliation(s)
- Maria Buniel
- Rammelkamp Center for Education and Research, MetroHealth Campus of Case Western Reserve University, Cleveland, Ohio 44109-1998, USA
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