Duhm J, Heller J, Zicha J
Institute of Physiology, University of Munich, Germany.
Clin Exp Hypertens A. 1990;12(7):1203-22. doi: 10.3109/10641969009074749.
Kinetics of ouabain-sensitive, furosemide-sensitive (FS), bumetanide-sensitive (BS) and -resistant Na+ and K+ transport were studied in erythrocytes of Prague hypertensive rats (PHR) and Prague normotensive rats (PNR). Maximal transport rates (Vmax) and apparent affinities for either intracellular Na+ or extracellular K+ (replaced by Rb+) were determined in red cells in which Na+ content varied around the physiological range and that were incubated in Na+ media. No major differences between PHR and PNR were disclosed in the kinetics of ion transport mediated by the Na(+)-K+ pump or BS inward Na(+)-K+ cotransport. FS Rb+ uptake was higher (due to a greater Vmax) in red cells of PHR as compared to PNR. In cells with a lowered Na+ content this elevation of FS Rb+ uptake was largely due to an augmented K(+)-Cl- cotransport which exhibits a low affinity for Rb+o and is blocked by 1 mM furosemide but not by 10 microM bumetanide. Red cells of PHR and PNR strains did not differ in either Na+ or Rb+ leaks. A slight increase of red cell Na+ content in PHR was evaluated in terms of the pump-leak concept. The present study did not reveal any obvious kinetic abnormalities of red cell cation transport the presence of which in tissues involved in blood pressure regulation would favor the development or the maintenance of genetic hypertension in PHR.
研究了哇巴因敏感、呋塞米敏感（FS）、布美他尼敏感（BS）和耐药的Na⁺和K⁺转运在布拉格高血压大鼠（PHR）和布拉格正常血压大鼠（PNR）红细胞中的动力学。在Na⁺含量在生理范围内变化且在Na⁺培养基中孵育的红细胞中，测定了细胞内Na⁺或细胞外K⁺（用Rb⁺替代）的最大转运速率（Vmax）和表观亲和力。在由Na⁺-K⁺泵或BS内向Na⁺-K⁺协同转运介导的离子转运动力学方面，未发现PHR和PNR之间有重大差异。与PNR相比，PHR红细胞中的FS Rb⁺摄取更高（由于更大的Vmax）。在Na⁺含量降低的细胞中，FS Rb⁺摄取的这种升高在很大程度上是由于K⁺-Cl⁻协同转运增加，该协同转运对Rb⁺o的亲和力较低，可被1 mM呋塞米阻断，但不能被10 μM布美他尼阻断。PHR和PNR品系的红细胞在Na⁺或Rb⁺泄漏方面没有差异。根据泵-漏概念评估了PHR中红细胞Na⁺含量的轻微增加。本研究未发现红细胞阳离子转运有任何明显的动力学异常，而在参与血压调节的组织中存在这种异常将有利于PHR中遗传性高血压的发展或维持。
