scholarly journals Naked mole-rats lack cold sensitivity before and after nerve injury

2020 ◽  
Vol 16 ◽  
pp. 174480692095510
Author(s):  
Sandra J Poulson ◽  
Ahmed Aldarraji ◽  
Iqra I Arain ◽  
Natalia Dziekonski ◽  
Keza Motlana ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Nerve Injury ◽  
Messenger Rna ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Receptor Expression ◽  
Mustard Oil ◽  
Cold Sensitivity ◽  
Mechanical Stimuli ◽  
Cold Stimulation

Neuropathic pain is a chronic disease state resulting from injury to the nervous system. This type of pain often responds poorly to standard treatments and occasionally may get worse instead of better over time. Patients who experience neuropathic pain report sensitivity to cold and mechanical stimuli. Since the nociceptive system of African naked mole-rats contains unique adaptations that result in insensitivity to some pain types, we investigated whether naked mole-rats may be resilient to sensitivity following nerve injury. Using the spared nerve injury model of neuropathic pain, we showed that sensitivity to mechanical stimuli developed similarly in mice and naked mole-rats. However, naked mole-rats lacked sensitivity to mild cold stimulation after nerve injury, while mice developed robust cold sensitivity. We pursued this response deficit by testing behavior to activators of transient receptor potential (TRP) receptors involved in detecting cold in naïve animals. Following mustard oil, a TRPA1 activator, naked mole-rats responded similarly to mice. Conversely, icilin, a TRPM8 agonist, did not evoke pain behavior in naked mole-rats when compared with mice. Finally, we used RNAscope to probe for TRPA1 and TRPM8 messenger RNA expression in dorsal root ganglia of both species. We found increased TRPA1 messenger RNA, but decreased TRPM8 punctae in naked mole-rats when compared with mice. Our findings likely reflect species differences due to evolutionary environmental responses that are not easily explained by differences in receptor expression between the species.

scholarly journals Satellite glial cells in sensory ganglia express functional transient receptor potential ankyrin 1 that is sensitized in neuropathic and inflammatory pain

2020 ◽  
Vol 16 ◽  
pp. 174480692092542 ◽  
Author(s):  
Seung Min Shin ◽  
Brandon Itson-Zoske ◽  
Yongsong Cai ◽  
Chensheng Qiu ◽  
Bin Pan ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Nerve Injury ◽  
Glial Cells ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Allyl Isothiocyanate ◽  
Sensory Ganglia ◽  
Satellite Glial Cells ◽  
Intracellular Ca ◽  
Transient Receptor

Transient receptor potential ankyrin 1 (TRPA1) is well documented as an important molecule in pain hypersensitivity following inflammation and nerve injury and in many other cellular biological processes. Here, we show that TRPA1 is expressed not only by sensory neurons of the dorsal root ganglia (DRG) but also in their adjacent satellite glial cells (SGCs), as well as nonmyelinating Schwann cells. TRPA1 immunoreactivity is also detected in various cutaneous structures of sensory neuronal terminals, including small and large caliber cutaneous sensory fibers and endings. The SGC-expressed TRPA1 is functional. Like DRG neurons, dissociated SGCs exhibit a robust response to the TRPA1-selective agonist allyl isothiocyanate (AITC) by an increase of intracellular Ca2+ concentration ([Ca2+]i). These responses are abolished by the TRPA1 antagonist HC030031 and are absent in SGCs and neurons from global TRPA1 null mice. SGCs and neurons harvested from DRG proximal to painful tissue inflammation induced by plantar injection of complete Freund’s adjuvant show greater AITC-evoked elevation of [Ca2+]i and slower recovery compared to sham controls. Similar TRPA1 sensitization occurs in both SGCs and neurons during neuropathic pain induced by spared nerve injury. Together, these results show that functional TRPA1 is expressed by sensory ganglia SGCs, and TRPA1 function in SGCs is enhanced after both peripheral inflammation and nerve injury, and suggest that TRPA1 in SGCs may contribute to inflammatory and neuropathic pain.

scholarly journals Oxidized lipids and signaling pathways of G2A receptor involved in nerve injury induced neuropathic pain

2021 ◽  
Author(s):  
◽  
Tabea Osthues
Keyword(s):  
Neuropathic Pain ◽  
Signaling Pathways ◽  
Nerve Injury ◽  
Inflammatory Mediators ◽  
Pain Perception ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Wild Type ◽  
Injured Nerve

Neuropathic pain, a form of chronic pain, is a steadily rising health problem due to health costs and increasing numbers of patients. Neuropathic pain conditions arise upon metabolic disorders, infections, chemotherapeutic treatment, trauma or nerve injury. Especially nerve injury induced neuropathic pain is characterized by spontaneous or ongoing pain due to neuroimmune interactions. Thereby, inflammatory mediators, released by the injured nerve, recruit to and activate immune cells at the site of injury. Those mediators further activate transient receptor potential vanilloid 1 (TRPV1), a known channel involved in pain perception, or bind to G-protein coupled receptors (GPCR) in peripheral nerve endings. The following activated second messenger signaling pathways lead to sensitization of TRPV1. One of those GPCRs is G2A. The overall aim of this thesis was to investigate the role of G2A in nerve-injury induced neuropathic pain. For this, the common mouse model of nerve-injury induced neuropathic pain, the spared-nerve injury, was used. As measurements with dynamic plantar aesthesiometer showed, G2A-deficiency leads to reduced mechanical hypersensitivity. Upon analysis with FACS, ELISA and Luminex a reduced number of macrophages and neutrophils at the injured nerve, as well as less inflammatory mediators (TNFα, IL-6, VEGF) in G2A-deficient animals was observed. In dorsal root ganglia (DRGs) there was only a reduced number of macrophages and less IL-12 observed in G2A-deficient animals. Additionally, in wild-type mice, G2A agonist 9-HODE was elevated at the injured nerve, as a LC-MS/MS analysis showed. To investigate the underlying pathways of G2A-9-HODE signaling, a proteom screen was performed. This screen revealed upregulation of multiple proteins involved in migration in wild-type macrophages. Additionally, Ca-Imaging and transwell migration assays showed that the G2A antagonist G2A11, had desensitizing effects on DRG neurons and inhibited macrophage migration. Overall, the results suggest that loss of G2A has dual effects. On the one hand loss of G2A is antinociceptive. On the other hand, G2A-deficiency leads to reduced inflammation, suggesting G2A as promising target in treatment of neuropathic pain. Here, an antagonist had inhibitory effects on the migration and the sensitization.

scholarly journals Role of PAR2 in regulating oxaliplatin-induced neuropathic pain via TRPA1

2015 ◽  
Vol 6 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Liujun Tian ◽  
Tianren Fan ◽  
Nan Zhou ◽  
Hui Guo ◽  
Weijie Zhang
Keyword(s):  
Neuropathic Pain ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Cold Sensitivity ◽  
Downstream Signaling ◽  
Lumbar Dorsal Root Ganglion ◽  
Transient Receptor ◽  
Underlying Mechanisms ◽  
Cold Hypersensitivity

AbstractOxaliplatin (OXL) is a third-generation chemotherapeutic agent commonly used to treat metastatic digestive tumors; however, one of the main limiting complications of OXL is neuropathic pain. In this study, the underlying mechanisms responsible for OXL evoked-neuropathic pain were examined. Using a rat model, the results demonstrated that intraperitoneal (i.p.) injection of OXL significantly increased mechanical pain and cold sensitivity as compared with control animals (P < 0.05 vs. control rats). Blocking proteinase-activated receptor 2 (PAR2) significantly attenuated mechanical pain and cold sensitivity observed in control rats and OXL rats (P < 0.05 vs. vehicle control). The attenuating effect of PAR2 on mechanical pain and cold sensitivity were significantly smaller in OXL-rats than in control rats. The role played by PAR2 downstream signaling pathways [namely, transient receptor potential ankyrin 1 (TRPA1)] in regulating OXL evoked-neuropathic pain was also examined. The data shows that TRPA1 expression was upregulated in the lumbar dorsal root ganglion (DRG) of OXL rats and blocking TRPA1 inhibited mechanical pain and heightened cold sensitivity (P <0.05 vs. control rats). Blocking PAR2 also significantly decreased TRPA1expression in the DRG. Findings in this study show that OXL intervention amplifies mechanical hyperalgesia and cold hypersensitivity and PAR2 plays an important role in regulating OXLinduced neuropathic pain via TRPA1 pathways.

Effects of low- and high-frequency electroacupuncture on protein expression and distribution of TRPV1 and P2X3 in rats with peripheral nerve injury

2020 ◽  
pp. 096452842096884
Author(s):  
Junying Du ◽  
Junfan Fang ◽  
Xuaner Xiang ◽  
Jie Yu ◽  
Xiaoqin Le ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Protein Expression ◽  
Nerve Injury ◽  
Transient Receptor Potential ◽  
Intrathecal Injection ◽  
Receptor Potential ◽  
P2x Receptor ◽  
Sprague Dawley ◽  
Withdrawal Threshold ◽  
Analgesic Effects

Background: Whether electroacupuncture (EA) stimulation at different frequencies has a similar effect on spared nerve injury (SNI) as other neuropathic pain models, and how EA at different frequencies causes distinct analgesic effects on neuropathic pain is still not clear. Methods: Adult male Sprague-Dawley rats were randomly divided into sham SNI, SNI, 2 Hz, 100 Hz and sham EA groups. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were measured. EA was performed once a day on days 1 to 14 after SNI. The expressions of transient receptor potential cation subfamily V member 1 (TRPV1) and peripheral purinergic P2X receptor 3 (P2X3) were determined by western blotting and immunofluorescence. TRPV1 siRNA and P2X3 siRNA were administered by intrathecal injection. TRPV1 or P2X3 agonists were combined with EA. Results: There were significant decreases in PWT, but no changes in PWL in the 14 days after SNI. EA using 2- or 100-Hz stimulation similarly increased PWT at every time point. The cytosol protein expression of P2X3 in the L4–L6 dorsal root ganglia (DRG) increased, but the expression of TRPV1 decreased in the SNI model. Both these effects were ameliorated by EA, with 2-Hz stimulation having a stronger effect than 100-Hz stimulation. Blocking either TRPV1 or P2X3 specific siRNAs attenuated the decreased PWT induced by SNI. Administration of either a TRPV1 or P2X3 agonist inhibited EA analgesia. Conclusion: 2- and 100-Hz EA similarly induced analgesic effects in SNI. This effect was related to up-regulation and down-regulation, respectively, of cytosol protein expression of P2X3 and TRPV1 in L4–L6 DRG, with 2 Hz having a better effect than 100 Hz.

scholarly journals Inhibition of TRPA1 and IL-6 Signal Alleviates Neuropathic Pain Following Chemotherapeutic Bortezomib

2019 ◽  
pp. 845-855 ◽  
Author(s):  
D. LIU ◽  
M. SUN ◽  
D. XU ◽  
X. MA ◽  
D. GAO ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Root Ganglion ◽  
Signaling Pathways ◽  
P38 Mapk ◽  
Dorsal Root ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Sensory Nerves ◽  
Cold Sensitivity ◽  
Systemic Injection

Bortezomib (BTZ) is used as a chemotherapeutic agent for the treatment of multiple myeloma. Nevertheless, one of the significant limiting complications of BTZ is painful peripheral neuropathy during BTZ therapy. Thus, in this study we examined signaling pathways of interleukin-6 (IL-6) and transient receptor potential ankyrin 1 (TRPA1) in the sensory nerves responsible for neuropathic pain induced by BTZ and further determined if influencing the pathways can improve neuropathic pain. ELISA and western blot analysis were used to examine the levels of IL-6, and IL-6 receptor (IL-6R), TRPA1 and p38-MAPK and JNK signal in the lumbar dorsal root ganglion. Behavioral test was performed to determine mechanical and cold sensitivity in a rat model. Our results showed that systemic injection of BTZ increased mechanical pain and cold sensitivity as compared with control animals. Data also showed that protein expression of TRPA1 and IL-6R was upregulated in the dorsal root ganglion of BTZ rats and blocking TRPA1 attenuated mechanical and cold sensitivity in control rats and BTZ rats. Notably, the inhibitory effect of blocking TRPA1 was smaller in BTZ rats than that in control rats. In addition, a blockade of IL-6 signal attenuated intracellular p38-MAPK and JNK in the sensory neuron. This also decreased TRPA1 expression and alleviated mechanical hyperalgesia and cold hypersensitivity in BTZ rats. In conclusion, we revealed specific signaling pathways leading to neuropathic pain induced by chemotherapeutic BTZ, including IL-6-TRPA1, suggesting that blocking these signals is beneficial to alleviate neuropathic pain during BTZ intervention

scholarly journals Increase in IGF-1 Expression in the Injured Infraorbital Nerve and Possible Implications for Orofacial Neuropathic Pain

2019 ◽  
Vol 20 (24) ◽  
pp. 6360 ◽  
Author(s):  
Shiori Sugawara ◽  
Masamichi Shinoda ◽  
Yoshinori Hayashi ◽  
Hiroto Saito ◽  
Sayaka Asano ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Peripheral Nerve ◽  
Nerve Injury ◽  
Mechanical Allodynia ◽  
Transient Receptor Potential ◽  
Cervical Spinal Cord ◽  
Receptor Potential ◽  
Infraorbital Nerve ◽  
Transient Receptor Potential Vanilloid ◽  
Whisker Pad

Insulin-like growth factor-1 (IGF-1) is upregulated in the injured peripheral nerve bundle and controls nociceptive neuronal excitability associated with peripheral nerve injury. Here, we examined the involvement of IGF-1 signaling in orofacial neuropathic pain following infraorbital nerve injury (IONI) in rats. IONI promoted macrophage accumulation in the injured ION, as well as in the ipsilateral trigeminal ganglion (TG), and induced mechanical allodynia of the whisker pad skin together with the enhancement of neuronal activities in the subnucleus caudalis of the spinal trigeminal nucleus and in the upper cervical spinal cord. The levels of IGF-1 released by infiltrating macrophages into the injured ION and the TG were significantly increased. The IONI-induced the number of transient receptor potential vanilloid (TRPV) subfamily type 4 (TRPV4) upregulation in TRPV subfamily type 2 (TRPV2)-positive small-sized, and medium-sized TG neurons were inhibited by peripheral TRPV2 antagonism. Furthermore, the IONI-induced mechanical allodynia was suppressed by TRPV4 antagonism in the whisker pad skin. These results suggest that IGF-1 released by macrophages accumulating in the injured ION binds to TRPV2, which increases TRPV4 expression in TG neurons innervating the whisker pad skin, ultimately resulting in mechanical allodynia of the whisker pad skin.

scholarly journals Oxytocin-Dependent Regulation of TRPs Expression in Trigeminal Ganglion Neurons Attenuates Orofacial Neuropathic Pain following Infraorbital Nerve Injury in Rats

2020 ◽  
Vol 21 (23) ◽  
pp. 9173
Author(s):  
Masatoshi Ando ◽  
Yoshinori Hayashi ◽  
Suzuro Hitomi ◽  
Ikuko Shibuta ◽  
Akihiko Furukawa ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Nerve Injury ◽  
Trigeminal Ganglion ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Infraorbital Nerve ◽  
Transient Receptor Potential Vanilloid ◽  
Withdrawal Threshold ◽  
Whisker Pad ◽  
Ganglion Neurons

We evaluated the mechanisms underlying the oxytocin (OXT)-induced analgesic effect on orofacial neuropathic pain following infraorbital nerve injury (IONI). IONI was established through tight ligation of one-third of the infraorbital nerve thickness. Subsequently, the head withdrawal threshold for mechanical stimulation (MHWT) of the whisker pad skin was measured using a von Frey filament. Trigeminal ganglion (TG) neurons innervating the whisker pad skin were identified using a retrograde labeling technique. OXT receptor-immunoreactive (IR), transient receptor potential vanilloid 1 (TRPV1)-IR, and TRPV4-IR TG neurons innervating the whisker pad skin were examined on post-IONI day 5. The MHWT remarkably decreased from post-IONI day 1 onward. OXT application to the nerve-injured site attenuated the decrease in MHWT from day 5 onward. TRPV1 or TRPV4 antagonism significantly suppressed the decrement of MHWT following IONI. OXT receptors were expressed in the uninjured and Fluoro-Gold (FG)-labeled TG neurons. Furthermore, there was an increase in the number of FG-labeled TRPV1-IR and TRPV4-IR TG neurons, which was inhibited by administering OXT. This inhibition was suppressed by co-administration with an OXT receptor antagonist. These findings suggest that OXT application inhibits the increase in TRPV1-IR and TRPV4-IR TG neurons innervating the whisker pad skin, which attenuates post-IONI orofacial mechanical allodynia.

scholarly journals Calmodulin Supports TRPA1 Channel Association with Opioid Receptors and Glutamate NMDA Receptors in the Nervous Tissue

2020 ◽  
Vol 22 (1) ◽  
pp. 229
Author(s):  
Elsa Cortés-Montero ◽  
María Rodríguez-Muñoz ◽  
M. Carmen Ruiz-Cantero ◽  
Enrique J. Cobos ◽  
Pilar Sánchez-Blázquez ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Opioid Receptors ◽  
Nervous Tissue ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Mechanical Stimuli ◽  
Delta Opioid Receptors ◽  
Relevant Role ◽  
Transient Receptor

Transient receptor potential ankyrin member 1 (TRPA1) belongs to the family of thermo TRP cation channels that detect harmful temperatures, acids and numerous chemical pollutants. TRPA1 is expressed in nervous tissue, where it participates in the genesis of nociceptive signals in response to noxious stimuli and mediates mechanical hyperalgesia and allodynia associated with different neuropathies. The glutamate N-methyl-d-aspartate receptor (NMDAR), which plays a relevant role in allodynia to mechanical stimuli, is connected via histidine triad nucleotide-binding protein 1 (HINT1) and type 1 sigma receptor (σ1R) to mu-opioid receptors (MORs), which mediate the most potent pain relief. Notably, neuropathic pain causes a reduction in MOR antinociceptive efficacy, which can be reversed by blocking spinal NMDARs and TRPA1 channels. Thus, we studied whether TRPA1 channels form complexes with MORs and NMDARs that may be implicated in the aforementioned nociceptive signals. Our data suggest that TRPA1 channels functionally associate with MORs, delta opioid receptors and NMDARs in the dorsal root ganglia, the spinal cord and brain areas. These associations were altered in response to pharmacological interventions and the induction of inflammatory and also neuropathic pain. The MOR-TRPA1 and NMDAR-TRPA1 associations do not require HINT1 or σ1R but appear to be mediated by calcium-activated calmodulin. Thus, TRPA1 channels may associate with NMDARs to promote ascending acute and chronic pain signals and to control MOR antinociception.

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