Pinheiro, Ana RitaParamos-de-Carvalho, DiogoCertal, MarianaCosta, Maria AdelinaCosta, CristinaMagalhães-Cardoso, Maria TeresaFerreirinha, FátimaSévigny, JeanCorreia-de-Sá, Paulo2019-07-112019-07-112013http://hdl.handle.net/10400.22/14340Changes in the regulation of connective tissue ATP-mediated mechano-transduction and remodeling may be an important link to the pathogenesis of chronic pain. It has been demonstrated that mast cell-derived histamine plays an important role in painful fibrotic diseases. Here we analyzed the involvement of ATP in the response of human subcutaneous fibroblasts to histamine. Acute histamine application caused a rise in intracellular Ca(2+) ([Ca(2+)]i) and ATP release from human subcutaneous fibroblasts via H1 receptor activation. Histamine-induced [Ca(2+)]i rise was partially attenuated by apyrase, an enzyme that inactivates extracellular ATP, and by blocking P2 purinoceptors with pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt and reactive blue 2. [Ca(2+)]i accumulation caused by histamine was also reduced upon blocking pannexin-1 hemichannels with (10)Panx, probenecid, or carbenoxolone but not when connexin hemichannels were inhibited with mefloquine or 2-octanol. Brefeldin A, an inhibitor of vesicular exocytosis, also did not block histamine-induced [Ca(2+)]i mobilization. Prolonged exposure of human subcutaneous fibroblast cultures to histamine favored cell growth and type I collagen synthesis via the activation of H1 receptor. This effect was mimicked by ATP and its metabolite, ADP, whereas the selective P2Y1 receptor antagonist, MRS2179, partially attenuated histamine-induced cell growth and type I collagen production. Expression of pannexin-1 and ADP-sensitive P2Y1 receptor on human subcutaneous fibroblasts was confirmed by immunofluorescence confocal microscopy and Western blot analysis. In conclusion, histamine induces ATP release from human subcutaneous fibroblasts, via pannexin-1 hemichannels, leading to [Ca(2+)]i mobilization and cell growth through the cooperation of H1 and P2 (probably P2Y1) receptors.engAdenosine DiphosphateAdenosine TriphosphateAnti-Bacterial AgentsAntimalarialsBrefeldin ACalciumCell ProliferationCells, CulturedCollagen Type IConnexinsExocytosisFibroblastsGene Expression RegulationHistamineHistamine AgonistsMast CellsMefloquineNerve Tissue ProteinsOctanolsPurinergic P2Y Receptor AntagonistsReceptors, Histamine H1Receptors, Purinergic P2Y1journal article10.1074/jbc.M113.460865