adenosine-3--5--cyclic-phosphorothioate and 14-15-episulfide-eicosatrienoic-acid

An initial step in endothelium-derived hyperpolarizing factor-mediated responses is endothelial cell hyperpolarization. Here we address the mechanisms by which cytochrome P450 (CYP)-derived epoxyeicosatrienoic acids (EETs) contribute to this effect in native and cultured endothelial cells.. In native CYP2C-expressing endothelial cells, bradykinin elicited a Ca(2+) influx that was potentiated by the soluble epoxide hydrolase inhibitor, 1-adamantyl-3-cyclohexylurea (ACU), and attenuated by CYP inhibition. Similar effects were observed in cultured endothelial cells overexpressing CYP2C9, but not in CYP2C9-deficient cells, and were prevented by the EET antagonist 14,15-epoxyeicosa-5(Z)-enoic acid as well as by the cAMP antagonist, Rp-cAMPS. The effects on Ca(2+) were mirrored by prolongation of the bradykinin-induced hyperpolarization. Ruthenium red and the combination of charybdotoxin and apamin prevented the latter effect, suggesting that Trp channel activation increases Ca(2+) influx and prolongs the activation of Ca(2+)-dependent K(+) (K(Ca)) channels. Indeed, overexpression of CYP2C9 enhanced the agonist-induced translocation of a TrpC6-V5 fusion protein to caveolin-1-rich areas of the endothelial cell membrane, which was prevented by Rp-cAMPS and mimicked by 11,12-EET.. Elevated EET levels regulate Ca(2+) influx into endothelial cells and the subsequent activation of K(Ca) channels, via a cAMP/PKA-dependent mechanism that involves the intracellular translocation of Trp channels.

Topics: 8,11,14-Eicosatrienoic Acid; Adamantane; Apamin; Biological Factors; Bradykinin; Calcium Signaling; Caveolin 1; Cell Membrane; Cells, Cultured; Charybdotoxin; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Eicosanoic Acids; Endothelial Cells; Enzyme Inhibitors; Epoxide Hydrolases; Humans; Membrane Potentials; Membrane Transport Modulators; Miconazole; Protein Transport; Recombinant Fusion Proteins; RNA, Messenger; Ruthenium Red; Thionucleotides; Time Factors; Transfection; TRPC Cation Channels; Vasodilator Agents