间硝苯地平和硝苯地平对异丙肾上腺素所致心肌肥厚的影响

Effects of m nifedipine and nifedipine on cardiac hypertrophy induced by isoprenaline

异丙肾上腺素（Ｉｓｏ）０．０２ｍｇ·ｋｇ－１每日２次，连续ｓｃ５ｗｋ可引起大鼠左心室肥厚（ＬＶＨ），降低心肌顺应性；并使心肌僵硬度常数增加９２％，冠脉流量降低１４％．与对照组相比，Ｉｓｏ还使心肌线粒体，主动脉和尾动脉壁Ｃａ２＋含量分别增加了９５％，７３％和６９％．大鼠于Ｉｓｏｓｃ１ｗｋ后分别给予间硝苯地平和硝苯地平１０ｍｇ·ｋｇ－１ｉｇ每日２次４ｗｋ，均显著减轻Ｉｓｏ引起的ＬＶＨ，改善冠脉血液供应，降低心肌僵硬度，提高心肌顺应性，并减少心肌细胞线粒体，主动脉和尾动脉壁的Ｃａ２＋含量．

After treatment with m nifedipine ( m Nif) or nifedipine (Nif) 10 mg·kg -1 ig twice a day for four weeks, the increases in the ratio of heart wet weight to body weight which was induced by a continued adminidstration of isoprenaline (Iso) 0.02 mg·kg -1 sc twice a day for five weeks were significantly attenuated. The coronary flow was higher in m Nif (12.2±1.0 mL·min -1 ) and Nif groups (12.2±0.9 mL·min -1 ) than that in Iso group (10.3±0.4 mL·min -1 , P <0.01). The myocardial compliances were improved and the stiffness coefficients were decreased by the two drugs. Compared to Iso group, the calcium contents of myocardial mitochondria, aorta and tail artery were reduced remarkably in the m Nif treated group (decreased by 42%, 41% and 40% respectively) and Nif treated group (decreased by 38%, 35% and 37% respectively). Thus this study showed that m Nif and Nif regressed cardiac mass induced by Iso in rats through the mechanisms that may be associated with hemodynamic changes especially diastolic function of heart and inhibiting transmembrane calcium influx.