Mechanism of RhoA/Rho kinase activation in endothelin-1- induced contraction in rabbit basilar artery.
This study was undertaken to demonstrate the role of the RhoA/Rho kinase pathway in endothelin-1 (ET-1)-induced contraction of the rabbit basilar artery. Isometric tension and Western blot were used to examine ET-1-induced contraction and RhoA activation. The upstream effect on ET-1-induced RhoA activity was determined by using ET(A) and ET(B) receptor antagonists, protein kinase C (PKC), tyrosine kinase, and phosphatidylinositol-3 kinase inhibitors. The downstream effect of ET-1-induced contraction and RhoA activity was studied in the presence of the Rho kinase inhibitor Y-27632. The effect of Rho kinase inhibitor on ET-1-induced myosin light chain (MLC) phosphorylation was investigated by using urea-glycerol-PAGE immunoblotting. We found 1) ET-1 increased RhoA activity (membrane binding RhoA) in a concentration-dependent manner; 2) ET(A), but not ET(B), receptor antagonist abolished the effect of ET-1 on RhoA activation; 3) phosphodylinositol-3 kinase inhibitor, but not PKC and tyrosine kinase inhibitors, reduced ET-1-induced RhoA activation; 4) Rho kinase inhibitor Y-27632 (10 microM) inhibited ET-1-induced contraction; and 5) ET-1 increased the level of MLC phosphorylation. Rho kinase inhibitor Y-27632 reduced the effect of ET-1 on MLC phosphorylation. This study demonstrated that RhoA/Rho kinase activation is involved in ET-1-induced contraction in the rabbit basilar artery. Phosphodylinositol-3 kinase and MLC might be the upstream and downstream factors of RhoA activation.
Department of Neurosurgery, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA.
Liyan
L
Miao
Yun
Y
Dai
John
J
Zhang
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001488:Basilar Artery / Q000187:drug effects / Q000201:enzymology*; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010880:Piperidines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011817:Rabbits; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D020301:Vasospasm, Intracranial / Q000378:metabolism; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
D000959:Antihypertensive Agents; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D009842:Oligopeptides; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010880:Piperidines; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; C087220:BQ 610; C086539:BQ 788; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D011493:Protein Kinase C; D020742:rhoA GTP-Binding Protein