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Antinociceptive effect of two novel transient receptor potential melastatin 8 antagonists in acute and chronic pain models in rat
Author(s) -
De Caro Carmen,
Russo Roberto,
Avagliano Carmen,
Cristiano Claudia,
Calignano Antonio,
Aramini Andrea,
Bianchini Gianluca,
Allegretti Marcello,
Brandolini Laura
Publication year - 2018
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.14177
Subject(s) - trpm8 , transient receptor potential channel , nociception , neuropathic pain , medicine , chronic pain , sensory system , pharmacology , neuroscience , anesthesia , trpv1 , receptor , psychology
Background and Purpose Transient receptor potential (TRP) channels are a superfamily of non‐selective cation permeable channels involved in peripheral sensory signalling. Animal studies have shown that several TRPs are important players in pain modulation. Among them, the TRP melastatin 8 (TRPM8) has elicited more interest for its controversial role in nociception. This channel, expressed by a subpopulation of sensory neurons in dorsal root ganglia (DRG) and trigeminal ganglia (TG), is activated by cold temperatures and cooling agents. In experimental neuropathic pain models, an up‐regulation of this receptor in DRG and TG has been observed, suggesting a key role for TRPM8 in the development and maintenance of pain. Consistent with this hypothesis, TRPM8 knockout mice are less responsive to pain stimuli. Experimental Approach In this study, the therapeutic potential and efficacy of two novel TRPM8 antagonists, DFL23693 and DFL23448, were tested. Key Results Two potent and selective TRPM8 antagonists with distinct pharmacokinetic profiles, DFL23693 and DFL23448, have been fully characterized in vitro . In vivo studies in well‐established models, namely, the wet‐dog shaking test and changes in body temperature, confirmed their ability to block the TRPM8 channel. Finally, TRPM8 blockage resulted in a significant antinociceptive effect in formalin‐induced orofacial pain and in chronic constriction injury‐induced neuropathic pain, confirming an important role for this channel in pain perception. Conclusion and Implications Our findings, in agreement with previous literature, encourage further studies for a better comprehension of the therapeutic potential of TRPM8 blockers as novel agents for pain management.