Age-Related Decline in Beta Adrenergic and Adenosine A1 Receptor Function in the Heart Are Attenuated by Dietary

Previously published reports from this laboratory have shown that the antiadrenergic effect of adenosine A1 agonists declines with age in the rat heart [Gao et al. (1997) J Mol Cell Cardiol 29:593–602] and that this decline may be caused by a de-crease in coupling between adenosine A1 receptors (AdoA1R) and guanine nucleotide-binding proteins [Cai et al. (1997) Circ Res 81:1065–1071]. Dietary restriction (DR; 60 % calories of ad libitum) has been shown to attenuate age-related changes in cellular signal transduction pathways. Therefore, the present study investigated whether DR altered the age-related changes in AdoA1R-mediated function in senescent rat hearts. Ventric-ular membranes were isolated from the hearts of ad libitum (AL) fed and DR male F344 rats that were 6, 12 and 24 months of age. In AL rats, there was an age-related decline in isoproter