Steele T H, Challoner-Hue L
Department of Medicine, University of Wisconsin, Madison 53706.
Am J Physiol. 1988 Apr;254(4 Pt 2):F533-9. doi: 10.1152/ajprenal.1988.254.4.F533.
We examined responses to the calcium channel agonist, BAY-K 8644, of isolated perfused kidneys from Dahl salt-sensitive (DS) and -resistant (DR) rats that had been stabilized on high (HI) and low (LO) NaCl intakes. Mean arterial pressures of DS/HI rats exceeded those of the other three groups. BAY-K 8644 significantly increased the renal vascular resistance (RVR) of DS/HI and DS/LO kidneys, by 38 and 12%, respectively, but did not increase RVR of DR/HI or DR/LO kidneys significantly (6 and 2%, respectively). Increases in RVR and decreases in glomerular filtration rate of DS/HI kidneys exceeded those of DR/HI kidneys. Increases in the RVR of DS/LO kidneys exceeded those of DR/LO kidneys. Experiments utilizing the separate calcium channel agonist and antagonist enantiomers of BAY-K 8644 corroborated these findings, but at lower concentrations. "Chemical sympathectomy" with 6-hydroxydopamine increased the reactivity of kidneys from only high-NaCl animals to BAY-K 8644 without regard to Dahl S or R status. In conclusion, the DS kidney vasculature manifests an increase in responsiveness to this calcium channel agonist, independently of antecedent NaCl loading or high blood pressure. However, a high antecedent salt intake or hypertension enhances vascular responsiveness of the DS kidney to BAY-K 8644.
我们研究了来自已稳定摄入高（HI）和低（LO）氯化钠的达尔盐敏感（DS）和抗性（DR）大鼠的离体灌注肾脏对钙通道激动剂BAY-K 8644的反应。DS/HI大鼠的平均动脉压超过了其他三组。BAY-K 8644分别使DS/HI和DS/LO肾脏的肾血管阻力（RVR）显著增加38%和12%，但对DR/HI或DR/LO肾脏的RVR没有显著增加（分别为6%和2%）。DS/HI肾脏的RVR增加和肾小球滤过率降低超过了DR/HI肾脏。DS/LO肾脏的RVR增加超过了DR/LO肾脏。使用BAY-K 8644单独的钙通道激动剂和拮抗剂对映体进行的实验证实了这些发现，但浓度较低。用6-羟基多巴胺进行“化学交感神经切除术”仅增加了高盐动物肾脏对BAY-K 8644的反应性，而与达尔S或R状态无关。总之，DS肾血管系统对这种钙通道激动剂的反应性增加，与先前的氯化钠负荷或高血压无关。然而，先前的高盐摄入或高血压会增强DS肾脏对BAY-K 8644的血管反应性。
