De Simone G, Devereux R B, Volpe M, Camargo M J, Wallerson D C, Laragh J H
Department of Medicine, New York Hospital-Cornell Medical Center, New York 10021, USA.
Am J Physiol. 1996 Feb;270(2 Pt 2):H628-37. doi: 10.1152/ajpheart.1996.270.2.H628.
Supranormal left ventricular (LV) function has been reported in one-kidney, one-clip (1K,1C) and two-kidney, one-clip (2K,1C) Goldblatt hypertension. However, this finding might be at least partially due to mismatching endocardial rather than midwall fractional shortening to mean end-systolic stress. Accordingly, relations of echocardiographic endocardial and midwall shortening to circumferential end-systolic stress were calculated in 40 Wistar rats on 0.4% NaCl (r = -0.92, SE of estimate = 4.3% and r = -0.62, SE of estimate = 3.2%, both P < 0.0001). Midwall shortening as a percentage of predicted was related to LV chamber diameter in normal animals (r = 0.56, P < 0.0001). Endocardial and midwall shortening were compared as percentage of the normal values predicted from wall stress in 34 2K,1C and 19 1K,1C on 0.4% Na+ 8-9 wk after surgery. Use of midwall shortening reduced the number of these hypertensive rats with supranormal observed-to-predicted shortening ratio from 28 to 7.5% (P < 0.0001). Salt-deprived and high-salt diets (0.0035 and 4% NaCl, respectively) were given to 16 and 18 additional controls, 9 and 7 2K,1C, and 7 and 7 1K,1C. Salt-deprived sham animals had greater endocardial and midwall shortening (106 +/- 7 and 111 +/- 10% of predicted, both P < 0.002) than sham rats on 0.4% NaCl, whereas 4% NaCl had no effect. Five of sixteen salt-deprived sham rats had supranormal observed-to-predicted midwall shortening ratios for LV chamber size, suggesting an enhanced inotropic state. Salt-deprived and high-salt diets had negligible effects on LV performance in Goldblatt rats. Thus use of midwall shortening reduces the number of renovascular hypertensive rats with apparently increased LV function. Salt deprivation stimulates LV myocardial function in normal rats independent of chamber dimension (i.e., an indirect measure of preload) but does not influence LV performance in Goldblatt hypertension 8 wk after renal artery clipping.
据报道，在一侧肾、一侧夹闭（1K,1C）和两侧肾、一侧夹闭（2K,1C）的Goldblatt高血压模型中存在左心室（LV）功能超常。然而，这一发现可能至少部分归因于心内膜缩短与平均收缩末期应力的不匹配，而非中层心肌缩短。因此，计算了40只饮用0.4%氯化钠溶液的Wistar大鼠超声心动图心内膜和中层心肌缩短与圆周收缩末期应力的关系（r = -0.92，估计标准误 = 4.3%；r = -0.62，估计标准误 = 3.2%，P均 < 0.0001）。在正常动物中，中层心肌缩短占预测值的百分比与左心室腔直径相关（r = 0.56，P < 0.0001）。在术后8 - 9周，饮用0.4%氯化钠溶液的34只2K,1C大鼠和19只1K,1C大鼠中，将心内膜和中层心肌缩短作为根据壁应力预测的正常值的百分比进行比较。使用中层心肌缩短后，这些高血压大鼠中观察到的与预测的缩短率超常的数量从28%降至7.5%（P < 0.0001）。另外给16只和18只对照大鼠、9只和7只2K,1C大鼠以及7只和7只1K,1C大鼠分别给予低钠饮食（0.0035%氯化钠）和高钠饮食（4%氯化钠）。低钠饮食的假手术动物的心内膜和中层心肌缩短程度（分别为预测值的106±7%和111±10%，P均 < 0.002）高于饮用0.4%氯化钠溶液的假手术大鼠，而4%氯化钠饮食则无影响。16只低钠饮食的假手术大鼠中有5只左心室腔大小的观察到的与预测的中层心肌缩短率超常，提示心肌收缩力增强状态。低钠饮食和高钠饮食对Goldblatt大鼠的左心室功能影响可忽略不计。因此，使用中层心肌缩短可减少左心室功能明显增强的肾血管性高血压大鼠的数量。低钠饮食可刺激正常大鼠的左心室心肌功能，且与腔径无关（即前负荷的间接指标），但在肾动脉夹闭8周后对Goldblatt高血压大鼠的左心室功能无影响。
