Elodie Picard

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Background and Purpose T-type calcium channels, mainly the Cav3.2 subtype, are important contributors to the nociceptive signaling pathway. We investigated their involvement in inflammation and related pain-like symptoms. Experimental Approach The involvement of Cav3.2 and T-type channels was investigated using genetic and pharmacological inhibition to assess mechanical allodynia/hyperalgesia and edema development in two murine inflammatory pain models. The location of Cav3.2 involved in pain-like symptoms was studied in mice with Cav3.2 knocked out in C-low threshold mechanoreceptors (C-LTMR) and the use of ABT-639, a peripherally restricted T-type channel inhibitor. The anti-edematous effect of Cav3.2 inhibition was investigated in chimeric mice with immune cells deleted for Cav3.2. Lymphocytes and macrophages from either green fluorescent protein-targeted Cav3.2 or KO mice were used to determine the expression of Cav3.2 protein and the functional status of the cells. Key Results We showed the role of Cav3.2 channels in the development of pain-like symptoms and edema in the two murine inflammatory pain models. For the first time, we provide evidence of the involvement of Cav3.2 channels located on C-LTMRs in inflammatory pain at both peripheral and primary afferent terminals at the spinal level. We showed that Cav3.2 channels located in T cells and macrophages contribute to the inflammatory process. Conclusion and Implications This work highlights the crucial role of Cav3.2 channels in inflammation and related pain and suggests that targeting Cav3.2 channels with pharmacological agents could be an attractive and readily evaluable strategy in a clinical trial to relieve chronic inflammatory pain in affected patients.