Unchanged G-protein-coupled receptor kinase activity in the aging human heart.
OBJECTIVE
We sought to find out whether G-protein-coupled receptor kinase (GRK) activity is also increased in the aging human heart.


BACKGROUND
In the aging and failing human heart, cardiac beta-adrenoceptors (beta-AR) are desensitized. In heart failure (HF), an increase in cardiac GRK activity considerably contributes to this beta-AR desensitization.


METHODS
We assessed GRK activity (by in vitro rhodopsin phosphorylation) in the right atria (RA) from 16 children (mean age 9 +/- 2 years) and 17 elderly patients (mean age 67 +/- 2 years) without apparent HF and in the RA from four patients with end-stage HF.Cytosolic and membranous GRK activities in the RA from children were not significantly different from those in elderly patients; in contrast, cytosolic and membranous GRK activities in the RA from patients with end-stage HF were significantly increased.


CONCLUSIONS
In contrast to the failing human heart, in the aging human heart, GRK activity is not increased. Thus, GRK activity appears to not play an important role in beta-AR desensitization in the aging human heart.
Leineweber
Kirsten
K
Departments of Pathophysiology and Nephrology, University of Essen School of Medicine, Essen, Germany
Klapproth
Stefan
S
Beilfuss
Anja
A
Silber
Rolf-Edgar
RE
Heusch
Gerd
G
Philipp
Thomas
T
Brodde
Otto Erich
OE
D000262:Adenylyl Cyclases / Q000378:metabolism; D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D020517:Atrial Appendage / Q000201:enzymology*; D002648:Child; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism* / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000201:enzymology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000201:enzymology*; D051552:beta-Adrenergic Receptor Kinases
D017868:Cyclic AMP-Dependent Protein Kinases; D051552:beta-Adrenergic Receptor Kinases; D000262:Adenylyl Cyclases