Ischemic inactivation of G protein-coupled receptor kinase and altered desensitization of canine cardiac β-adrenergic receptors

G protein-coupled receptor kinases (GRKs) modulate myocardial beta-adrenergic receptor (betaAR) signaling. We examined whether GRK activity was altered 6, 24, and 96 hours after left anterior descending coronary artery ligation (LAD CAL) in the dog. GRK activity was measured in arrhythmogenic subepi...

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Published in:Circulation (New York, N.Y.) N.Y.), 2000-11, Vol.102 (20), p.2535-2540
Main Authors: XICHUN YU, MIN ZHANG, KYKER, Kimberly, PATTERSON, Eugene, BENOVIC, Jeffrey L, KEM, David C
Format: Article
Language:eng
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Summary:G protein-coupled receptor kinases (GRKs) modulate myocardial beta-adrenergic receptor (betaAR) signaling. We examined whether GRK activity was altered 6, 24, and 96 hours after left anterior descending coronary artery ligation (LAD CAL) in the dog. GRK activity was measured in arrhythmogenic subepicardial border zone (EBZ) tissue overlying the infarct and from nonischemic remote-site (RS) subepicardial tissue from the same animal. GRK activity in the ischemic EBZ was 15% of RS (P:=0.03, n=6) 24 hours after CAL and appeared to start as early as 6 hours through 96 hours. GRK activity and immunoblot data demonstrated a marked decrease of GRK2 but not GRK5 at 24 hours. EBZ tissue exhibited high-affinity binding for (-)-isoproterenol (K:(i) of 0. 076+/-0.026 nmol/L [SEM]) at 24 hours, which was not significantly different from control tissue from nonoperated animals (1.2+/-0.8 nmol/L, P:>0.05, n=6). A significantly lower K:(i) of 13.8+/-2.8 nmol/L (P:
ISSN:0009-7322
1524-4539