Angiotensin II stimulates extracellular signal-regulated kinase activity in intact pressurized rat mesenteric resistance arteries.
The activation of extracellular signal-regulated kinases 1/2 (ERK1/2) was assessed in isolated rat mesenteric resistance arteries (200-micrometer diameter) in a pressure myograph and stimulated for 5 minutes by angiotensin II (Ang II, 0.1 micromol/L) with a pressure of 70 mm Hg. ERK1/2 activity was measured by using an in-gel assay, and ERK1/2 phosphorylation was measured by Western blot analysis with use of a phospho-specific ERK1/2 antibody. Ang II (0.1 micromol/L) induced contraction (28% of phenylephrine contraction, 10 micromol/L). ERK kinase inhibitor PD98059 (10 micromol/L) attenuated this contraction by 36% but not that to phenylephrine or K(+) (60 mmol/L). In unpressurized arteries, Ang II increased ERK1/2 activity by 26%, and pressure (70 mm Hg) itself increased ERK1/2 activity by 72%. Ang II and pressure together acted synergistically, increasing ERK1/2 activity by 264%. Thus, in pressurized vessels, Ang II (0.1 micromol/L) increased ERK1/2 activity by 112%, calculated as [(364/172)-1]x100, which was confirmed by a measured 72% increase in ERK1/2 phosphorylation. Ang II type 1 receptor blockade by candesartan (10 micromol/L) abolished the Ang II-induced increase in ERK1/2 activity, but Ang II type 2 receptor blockade (PD123319, 10 micromol/L) did not. The Ang II-induced increase in ERK1/2 activity was inhibited by protein kinase C inhibitors Ro-31-8220 (1 micromol/L) and Go-6976 (300 nmol/L) and tyrosine kinase inhibitors genistein (1 micromol/L, general) and herbimycin A (1 micromol/L, c-Src family). The present findings show for the first time in intact resistance arteries that ERK1/2 activation is rapidly regulated by Ang II, is synergistic with pressure, and is involved in contraction. The ERK1/2 signaling pathway apparently includes upstream protein kinase C and c-Src.
Matrougui
K
K
Department of Pharmacology, University of Aarhus, Aarhus, Denmark.
Eskildsen-Helmond
Y E
YE
Fiebeler
A
A
Henrion
D
D
Levy
B I
BI
Tedgui
A
A
Mulvany
M J
MJ
D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009213:Myography; D010656:Phenylephrine / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D015398:Signal Transduction; D014655:Vascular Resistance / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects
D057911:Angiotensin Receptor Antagonists; D004791:Enzyme Inhibitors; D005419:Flavonoids; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D000804:Angiotensin II; D010656:Phenylephrine; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D011188:Potassium; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one