title: Decreased protein kinase C activation mediates inhibitory effect of norathyriol on serotonin-mediated endothelial permeability.
abstract: We examined the mechanisms of norathyriol on the serotonin-induced increased permeability of rat heart endothelial cell monolayers. The present study showed that the activation of rat heart endothelial cell protein kinase C by phorbol myristate acetate led to the dose-dependent increase in endothelial permeability to albumin, an effect that was inhibited by staurosporine (a protein kinase inhibitor). Staurosporine also attenuated the serotonin-induced increase in permeability. Norathyriol abolished both serotonin- and phorbol myristate acetate-induced permeability. We investigated whether norathyriol, by inhibiting protein kinase C activation, attenuated the serotonin-induced permeability. Immunofluorescence studies demonstrated that norathyriol prevented the redistribution of protein kinase C isozymes following stimulation with serotonin. Western blot analysis showed that norathyriol significantly inhibited the serotonin-induced translocation of the alpha protein kinase C isozyme from the cytosolic to the particulate fraction. In conclusion, norathyriol attenuates the serotonin-induced permeability of rat heart endothelial cells to macromolecules in association with inhibition of protein kinase C activation. This decrease in endothelial cell permeability may be one of the mechanisms for the protective effects of norathyriol against edema formation in response to inflammatory agonists in vivo.
authors.affiliation: Graduate Institute of Pharmaceutical Chemistry, China Medical College, Taichung, Taiwan.
authors.forename: H Z
authors.initials: HZ
authors.lastname: Lee
authors.forename: W C
authors.initials: WC
authors.lastname: Lin
authors.forename: F T
authors.initials: FT
authors.lastname: Yeh
authors.forename: C N
authors.initials: CN
authors.lastname: Lin
authors.forename: C H
authors.initials: CH
authors.lastname: Wu
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D019311:Staurosporine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014966:Xanthenes / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D012702:Serotonin Antagonists; D014966:Xanthenes; D012701:Serotonin; C069053:norathyriol; D000242:Cyclic AMP; D011493:Protein Kinase C; D006152:Cyclic GMP; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate