Age-associated alternations in cardiac β-adrenergic receptor signaling
- Author:
Jing MA
;
Shiwen WANG
;
Ruiping XIAO
- Publication Type:Journal Article
- From:
Journal of Geriatric Cardiology
2005;2(4):254-257
- CountryChina
- Language:Chinese
-
Abstract:
During aging, cardiac contractile response to β-AR stimulation is decreased in humans and animal models. Recent studies demonstrate that the positive inotropic effects of both β1-AR and β2-AR stimulation are significantly decreased with aging.This is accompanied by decreases in both β-AR subtype densities and a reduction in membrane adenylyl cyclase activity. However,neither G protein-coupled receptor kinases (GRKs) nor inhibitory G proteins (Gi) appears to contribute to the age-associated reduction in the β-AR modulation of contraction. Thus, while both aging and chronic heart failure exhibit a diminution in cardiac β-AR responsiveness, only heart failure exhibits increased GRK-mediated desensitization ofβ-Ars and an upregulation of Gi proteins.
