Combined effects of age and dietary fat on beta 1-receptors and Ca2+ channels in rat hearts.
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 [3H]nitrendipine 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.
Gudmundsdottir
E
E
Science Institute, University of Iceland, Reykjavík.
Benediktsdóttir
V E
VE
Gudbjarnason
S
S
D000375:Aging / Q000502:physiology*; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D004041:Dietary Fats / Q000032:analysis / Q000494:pharmacology*; D004082:Dihydroalprenolol / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000032:analysis / Q000494:pharmacology; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D009568:Nitrendipine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000502:physiology
D001095:Arachidonic Acids; D015220:Calcium Channels; D004041:Dietary Fats; D005231:Fatty Acids, Unsaturated; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D009568:Nitrendipine