Capasso J M, Malhotra A, Scheuer J, Sonnenblick E H
Circ Res. 1986 Apr;58(4):445-60. doi: 10.1161/01.res.58.4.445.
The effects of renovascular hypertension on the biochemical, contractile, and electrical performance of myocardial tissue from rats of various ages has been examined. Male Fischer rats, 2, 7, 12, and 17 months old, were made hypertensive by constriction of the left renal artery. Ten weeks after the onset of hypertension, left ventricular papillary muscles were isolated from those four groups when 5, 10, 15, and 20 months old, respectively. Mechanical performance and transmembrane electrical events were recorded simultaneously. Contractile protein enzyme activity was determined in the same hearts from which papillary muscles were used for acquisition of mechanical and electrical information. There was a slight increase in blood pressure in control groups as a function of age while blood pressure maintained a range of approximately 179-188 mm Hg for all hypertensive groups. Heart weight of control animals increased significantly from 5 months to 20 months of age from 539 +/- 26 to 1088 +/- 56 mg, representing an increase of 101%. In hypertensive animals, heart weight increased 50% in 5-month-, 15% in 10-month-, 50% in 15-month-, and 11.7% in 20-month-old animals. Although control groups revealed alterations in mechanical, electrical, and biochemical parameters that increased as a function of age, the magnitude of the biochemical, contractile, and electrical response to hypertension varied monotonically with the extent of myocardial hypertrophy, rather than age per se. Adaptation to the stress of hypertension was observed in each age group, and was revealed as prolongation of mechanical and electrical timing parameters, depression of the load-velocity relation, and contractile protein enzyme activity. Thus, the stress of hypertension, which was tolerated by the 10- and 20-month-old animals with lesser relative hypertrophy and lesser changes in measured parameters, may represent a differential adaptation to the stress of hypertension.
研究了肾血管性高血压对不同年龄大鼠心肌组织生化、收缩及电生理性能的影响。对2、7、12和17月龄的雄性Fischer大鼠，通过结扎左肾动脉使其患高血压。高血压发病10周后，分别从上述四组大鼠中分离出左心室乳头肌，此时大鼠年龄分别为5、10、15和20月龄。同时记录机械性能和跨膜电活动。在用于获取机械和电信息的同一心脏中测定收缩蛋白酶活性。对照组血压随年龄略有升高，而所有高血压组血压维持在约179 - 188 mmHg范围内。对照动物的心脏重量从5月龄到20月龄显著增加，从539±26 mg增至1088±56 mg，增加了101%。在高血压动物中，5月龄时心脏重量增加50%，10月龄时增加15%，15月龄时增加50%，20月龄时增加11.7%。虽然对照组显示机械、电和生化参数的改变随年龄增加，但高血压引起的生化、收缩和电反应的幅度随心肌肥厚程度单调变化，而非随年龄本身变化。在每个年龄组均观察到对高血压应激的适应，表现为机械和电时间参数延长、负荷 - 速度关系降低以及收缩蛋白酶活性改变。因此，10月龄和20月龄相对肥厚程度较小且测量参数变化较小的动物能够耐受的高血压应激，可能代表了对高血压应激的不同适应。
