title: Functional roles of the rho/rho kinase pathway and protein kinase C in the regulation of cerebrovascular constriction mediated by hemoglobin: relevance to subarachnoid hemorrhage and vasospasm.
abstract: Although there is evidence that the Rho/Rho kinase pathway and protein kinase C (PKC) are involved in the development of cerebral vasospasm, the mechanism by which subarachnoid hemorrhage (SAH) activates these pathways is unclear. A large body of evidence points to oxyhemoglobin (OxyHb) as a major causative component of blood clot responsible for vasospasm. Therefore, the present studies were conducted to explore whether the Rho/Rho kinase and PKC may be involved in a sustained vasoconstriction induced by OxyHb in cerebral arteries. OxyHb evoked sustained vasoconstriction in the endothelium-denuded rabbit basilar arteries, which was reversed by the selective inhibitors of Rho kinase, Y-27632, and HA-1077, with the IC50 values of 0.26+/-0.02 and 0.74+/-0.1 micromol/L, respectively. In quiescent cerebrovascular smooth muscle (CVSM) cells, OxyHb induced Rho translocation, as assessed by immunoblotting, with a time course, which paralleled the contractile action of OxyHb. Rho translocation was also observed in intact arteries stimulated with OxyHb for 24 hours (219%) and 48 hours (160%). The increase in Rho translocation was fully inhibited by GGTI-297, an inhibitor of Rho prenylation. OxyHb also caused significant translocation of both PKCalpha and PKCepsilon (P<0.01), which was maximal at the time corresponding to maximal tension developed in response to OxyHb. Ro-32-0432, an inhibitor of PKC, attenuated vasoconstriction mediated by OxyHb in basilar artery. These results show, for the first time, that OxyHb-mediated signaling in CVSM utilizes the Rho/Rho kinase and PKC-based mechanisms.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.
authors.forename: Grant
authors.initials: G
authors.lastname: Wickman
authors.forename: Christopher
authors.initials: C
authors.lastname: Lan
authors.forename: Bozena
authors.initials: B
authors.lastname: Vollrath
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000577:Amides / Q000494:pharmacology; D000818:Animals; D001488:Basilar Artery / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D001549:Benzamides / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010108:Oxyhemoglobins / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D054460:rho-Associated Kinases
chemical_list: D000577:Amides; D001549:Benzamides; D004791:Enzyme Inhibitors; C102520:GGTI 297; D007211:Indoles; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; D010108:Oxyhemoglobins; D011725:Pyridines; D011758:Pyrroles; C108830:Y 27632; C085989:Ro 32-0432; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D011493:Protein Kinase C; D020741:rho GTP-Binding Proteins; D013755:Tetradecanoylphorbol Acetate; C049347:fasudil