scholarly journals Characterization of New TRPM8 Modulators in Pain Perception

2019 ◽  
Vol 20 (22) ◽  
pp. 5544 ◽  
Author(s):  
Carmen De Caro ◽  
Claudia Cristiano ◽  
Carmen Avagliano ◽  
Alessia Bertamino ◽  
Carmine Ostacolo ◽  
...  

Background: Transient Receptor Potential Melastatin-8 (TRPM8) is a non-selective cation channel activated by cold temperature and by cooling agents. Several studies have proved that this channel is involved in pain perception. Although some studies indicate that TRPM8 inhibition is necessary to reduce acute and chronic pain, it is also reported that TRPM8 activation produces analgesia. These conflicting results could be explained by extracellular Ca2+-dependent desensitization that is induced by an excessive activation. Likely, this effect is due to phosphatidylinositol 4,5-bisphosphate (PIP2) depletion that leads to modification of TRPM8 channel activity, shifting voltage dependence towards more positive potentials. This phenomenon needs further evaluation and confirmation that would allow us to understand better the role of this channel and to develop new therapeutic strategies for controlling pain. Experimental approach: To understand the role of TRPM8 in pain perception, we tested two specific TRPM8-modulating compounds, an antagonist (IGM-18) and an agonist (IGM-5), in either acute or chronic animal pain models using male Sprague-Dawley rats or CD1 mice, after systemic or topical routes of administration. Results: IGM-18 and IGM-5 were fully characterized in vivo. The wet-dog shake test and the body temperature measurements highlighted the antagonist activity of IGM-18 on TRPM8 channels. Moreover, IGM-18 exerted an analgesic effect on formalin-induced orofacial pain and chronic constriction injury-induced neuropathic pain, demonstrating the involvement of TRPM8 channels in these two pain models. Finally, the results were consistent with TRPM8 downregulation by agonist IGM-5, due to its excessive activation. Conclusions: TRPM8 channels are strongly involved in pain modulation, and their selective antagonist is able to reduce both acute and chronic pain.

2018 ◽  
Vol 175 (10) ◽  
pp. 1691-1706 ◽  
Author(s):  
Carmen De Caro ◽  
Roberto Russo ◽  
Carmen Avagliano ◽  
Claudia Cristiano ◽  
Antonio Calignano ◽  
...  

2007 ◽  
Author(s):  
Jeffrey I. Gold ◽  
Trina Haselrig ◽  
D. Colette Nicolaou ◽  
Katharine A. Belmont

2012 ◽  
Vol 2 (3) ◽  
pp. 295-303 ◽  
Author(s):  
Gordon JG Asmundson ◽  
Holly A Parkerson ◽  
Mark Petter ◽  
Melanie Noel

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Shuzhuang Li ◽  
Tingting Cao ◽  
Shuo Ma ◽  
Xiujie Li ◽  
Yue Bi ◽  
...  

Background: It is an imperative task to identify the mechanisms responsible for post-traumatic secondary myocardial injury. Our previous experiments showed that mechanical trauma (MT) could induce secondary myocardial injury via oxidative stress. The transient potential receptor M2 (TRPM2) channel has emerged as an important Ca 2+ signaling mechanism in a variety of cells, contributing to cellular functions that include cytokine production, cell motility and cell death. However, the role of TRPM2 channel in nonlethal mechanical traumatic cardiac damage remains unclear. The aim of the present study was to investigate whether TRPM2 channel is involved in myocardial injury in rats subjected to nonlethal MT. Methods and results: Western blot was used to quantify TRPM2 protein levels in Ventricular myocytes of adult male Sprague Dawley rats. Up-regulation of TRPM2 channel protein was observed in the following 12h after MT. It was observed that plasma harvested from MT rats increased cytosolic Ca 2+ concentration dose-dependently in H9c2 cells. To verify the role of TRPM2 further, we administered TRPM2 blockers flufenamic acid (FFA, 100uM) and clotrimazole (CLZ, 30uM) respectively to inhibit Ca 2+ influx, which leads to attenuated intracelluar Ca 2+ overload and apoptosis induced by MT plasma in H9c2 cells. Those two TRPM2 blockers also improved cardiac dysfunction induced MT in rats. When we used TMB-8 (inhibitor of sarcoplasmic reticulum Ca 2+ store) to inhibit calcium store mobilization, intracellular Ca 2+ level, apoptosis and cardiac dysfunction were also ameliorated. However, the administration of KBR-7943 (inhibitor of Na/Ca exchanger) did not reverse the pathological process following MT. Conclusion: These results demonstrate that post-trauma pathological phenomena is associated with TRPM2 closely via a redox-sensitive signal transduction pathway (mainly via MT-initiated Ca 2+ influx, even calcium overload pathway) .We propose that treatments like blockage of TRPM2 channel-associated Ca 2+ influx and mobilization, may shed light on the novel therapeutic strategy in reducing cardiac injury and post-trauma multiple organ failure.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Myeounghoon Cha ◽  
Songyeon Choi ◽  
Kyeongmin Kim ◽  
Bae Hwan Lee

AbstractNeuropathic pain induced by a nerve injury can lead to chronic pain. Recent studies have reported hyperactive neural activities in the nociceptive-related area of the brain as a result of chronic pain. Although cerebral activities associated with hyperalgesia and allodynia in chronic pain models are difficult to represent with functional imaging techniques, advances in manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) could facilitate the visualization of the activation of pain-specific neural responses in the cerebral cortex. In order to investigate the alleviation of pain nociception by mammalian target of rapamycin (mTOR) modulation, we observed cerebrocortical excitability changes and compared regional Mn2+ enhancement after mTOR inhibition. At day 7 after nerve injury, drugs were applied into the intracortical area, and drug (Vehicle, Torin1, and XL388) effects were compared within groups using MEMRI. Therein, signal intensities of the insular cortex (IC), primary somatosensory cortex of the hind limb region, motor cortex 1/2, and anterior cingulate cortex regions were significantly reduced after application of mTOR inhibitors (Torin1 and XL388). Furthermore, rostral-caudal analysis of the IC indicated that the rostral region of the IC was more strongly associated with pain perception than the caudal region. Our data suggest that MEMRI can depict pain-related signal changes in the brain and that mTOR inhibition is closely correlated with pain modulation in chronic pain rats.


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