Nishimura H, Kubota J, Okabe M, Ueyama M, Oka T, Kawamura K
Third Department of Internal Medicine, Osaka Medical College, Japan.
Jpn Circ J. 1994 Feb;58(2):116-22. doi: 10.1253/jcj.58.116.
Left ventricular (LV) performance of the pharmacologically regressed heart in hypertension is still unclear. We compared LV function of the heart regressed by nifedipine with that of the hypertrophied heart in spontaneously hypertensive rats (SHR). Nifedipine (30 mg/kg/day in food) was given to 15-week-old male SHR for 20 weeks (n = 12). Age- and sex-matched SHR served as controls (n = 12). LV catheterization was performed using a micromanometer and cardiac output was determined by the thermodilution method. Hemodynamic studies were performed after washout of nifedipine (24 h), when blood pressure had returned to the untreated level. Peak pumping ability was assessed during acute volume loading with saline. Nifedipine significantly decreased blood pressure in conscious animals (222 +/- 11 to 201 +/- 12 mmHg, p < 0.01) and reduced LV weight (1.20 +/- 0.07 to 1.07 +/- 0.05g, p < 0.01). After washout of nifedipine, LV systolic and end-diastolic pressures, dp/dtmax and cardiac output determined under pentobarbital anesthesia were similar in the treated and untreated groups. Peak pumping ability during acute preload elevation was also similar in the 2 groups. Plasma norepinephrine was unaltered, and plasma renin activity was significantly lower in the treated rats (p < 0.05). These results indicate that nifedipine regressed LVH with a minimal reduction of blood pressure and without evidence of neurohumoral activation or volume retention. In conclusion, LV function of the heart regressed by nifedipine was preserved after a spontaneous rise in blood pressure and during acute preload elevation.
高血压患者经药物治疗后左心室（LV）功能仍不明确。我们比较了硝苯地平使心脏恢复正常后的左心室功能与自发性高血压大鼠（SHR）肥厚心脏的左心室功能。给15周龄雄性SHR喂食含硝苯地平（30 mg/kg/天）的食物，持续20周（n = 12）。年龄和性别匹配的SHR作为对照（n = 12）。使用微测压计进行左心室插管，并通过热稀释法测定心输出量。在硝苯地平洗脱（24小时）后，当血压恢复到未治疗水平时进行血流动力学研究。在用生理盐水进行急性容量负荷期间评估峰值泵血能力。硝苯地平显著降低清醒动物的血压（222±11至201±12 mmHg，p < 0.01）并减轻左心室重量（1.20±0.07至1.07±0.05 g，p < 0.01）。硝苯地平洗脱后，戊巴比妥麻醉下测定的治疗组和未治疗组的左心室收缩压和舒张压、dp/dtmax和心输出量相似。两组在急性前负荷升高期间的峰值泵血能力也相似。治疗组大鼠血浆去甲肾上腺素未改变，血浆肾素活性显著降低（p < 0.05）。这些结果表明，硝苯地平使左心室肥厚消退，同时血压降低最小，且无神经体液激活或容量潴留的证据。总之，硝苯地平使心脏恢复正常后的左心室功能在血压自发升高和急性前负荷升高期间得以保留。
