Myocardial distribution and regulation of GRK and beta-arrestin isoforms in XXXX in @entity35 .

@entity712 @entity47672 @entity35 @entity583 @entity21017 @entity21016
Myocardial G protein-coupled receptor kinase 2 ( @entity21016 ) has been shown to be involved in the pathophysiology of @entity712 ( @entity712 ). However, the cellular distribution of this isoform, as well as the other isoforms of the GRK-arrestin system, has not been studied in myocardial tissue. Thus myocardial expression and cellular distribution of the different GRK and arrestin isoforms were investigated in a @entity35 model of @entity712 . @entity35 subjected to ligation of the left coronary artery or sham operation were euthanized 2, 7, or 42 days after the surgical procedure. Myocardial @entity21016 , @entity47672 , beta-arrestin-1, and beta-arrestin-2 mRNA levels, but not that of @entity21017 , were induced in the failing hearts. Consistently, Western blot analysis of tissue extracts from the nonischemic region of the left ventricle revealed 3.0-, 2.6-, and 1.5-fold elevations of @entity21016 , @entity47672 , and beta-arrestin-1, respectively, 7 days after induction of @entity583 compared with the sham-operated @entity35 (P < 0.05). Immunohistochemical analysis of myocardial tissue sections and Western blot analysis of isolated cells revealed localization of @entity21016 and beta-arrestin-1 predominantly in endothelial cells. Conversely, @entity21017 was confined to cardiac myocytes. @entity47672 immunostaining appeared to be homogeneously distributed in the cellular elements of the myocardium. In conclusion, myocardial mRNA and protein levels of @entity21016 , @entity47672 , and beta-arrestin-1 are induced in postinfarction failure in @entity35 . The immunohistochemical analysis suggests that @entity21016 and beta-arrestin-1 may act as primary regulators of endothelial function. Conversely, the cellular distribution of @entity21017 and @entity47672 implicates these isoforms as putative regulators of cardiac myocyte function.
