Combined effects of age and dietary fat on beta 1-receptors and Ca2+ channels in rat hearts
Gudmundsdottir, E.; Benediktsdóttir, V.E.; Gudbjarnason, S.
American Journal of Physiology 260(1 Pt 2): H66-H72
1991
ISSN/ISBN: 0002-9513 PMID: 1847019 Document Number: 378462
Male Wistar rats were fed a standard diet or diets supplemented with 10% butter, 10% corn oil, or 10% cod liver oil from the age of 2 mo. At 7 and 24 mo of age, the fatty acid composition of total phospholipids was determined in ventricular crude sarcolemma preparations; binding capacity and affinity (1/Kd) of [3H]dihydroalprenolol and [3H]nitrendipine binding were also determined. The arachidonic acid level was significantly higher at 24 mo than at 7 mo of age in the membrane phospholipids in rats fed no extra fat, but in rats fed fat-supplemented diets, age had no effect. Affinity of Ca2+ channels for [3Hlnitrendipine decreased significantly in all dietary groups between 7 and 24 mo of age, whereas the affinity of beta 1-receptors for [3H]dihydroalprenolol increased in corn oil-fed rats. Density of beta 1-receptors decreased significantly in corn oil- and butter-fed rats and rats fed no extra fat between 7 and 24 mo of age, whereas the density of Ca2+ channels decreased significantly in corn oil-fed rats. We conclude that the antagonist binding properties of Ca2+ channels and beta 1-adrenergic receptors in rat hearts may change with age depending on the dietary fat.