Gudmundsdottir E, Benediktsdóttir V E, Gudbjarnason S
Science Institute, University of Iceland, Reykjavík.
Am J Physiol. 1991 Jan;260(1 Pt 2):H66-72. doi: 10.1152/ajpheart.1991.260.1.H66.
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.
从2月龄起，给雄性Wistar大鼠喂食标准饮食或添加10%黄油、10%玉米油或10%鱼肝油的饮食。在7月龄和24月龄时，测定心室粗肌膜制剂中总磷脂的脂肪酸组成；还测定了[3H]二氢阿普洛尔和[3H]尼群地平结合的结合能力和亲和力（1/Kd）。在未额外喂食脂肪的大鼠中，24月龄时膜磷脂中的花生四烯酸水平显著高于7月龄时，但在喂食高脂肪饮食的大鼠中，年龄没有影响。在7月龄至24月龄之间，所有饮食组中Ca2+通道对[3H]尼群地平的亲和力均显著降低，而在喂食玉米油的大鼠中，β1受体对[3H]二氢阿普洛尔的亲和力增加。在7月龄至24月龄之间，喂食玉米油、黄油的大鼠以及未额外喂食脂肪的大鼠中，β1受体密度显著降低，而喂食玉米油的大鼠中Ca2+通道密度显著降低。我们得出结论，大鼠心脏中Ca2+通道和β1肾上腺素能受体的拮抗剂结合特性可能会随年龄而变化，具体取决于饮食中的脂肪。
