Angiotensin Blockade Inhibits Activation of Mitogen-Activated Protein Kinases in Rat Balloon-Injured Artery

Background—The effect of balloon injury on the arterial signal transduction pathway has not been examined. In vitro studies show that extracellular signal-regulated kinases (ERKs) and c-Jun NH2-terminal kinases (JNKs), belonging to the mitogen-activated protein kinase (MAPK) family, play a critical role in the activation of transcription factor activator protein-1 (AP-1) and cell proliferation or apoptosis. However, the activation and role of MAPKs in vascular diseases in vivo remain to be determined. Therefore, we examined the effect of balloon injury on arterial MAPKs and the possible role of angiotensin II. Methods and Results—Arterial JNK and ERK activities were measured by in-gel kinase assay. AP-1 DNA binding activity was determined by gel mobility shift analysis. After balloon injury of rat carotid artery, JNK (p46JNK and p55JNK) and ERK (p44ERK and p42ERK) activities were increased as early as 2 minutes, reached their peak (6- to 18-fold) at 5 minutes, and thereafter rapidly declined to control le...