Earlier, we found that systemic administration of lipopolysaccharide (LPS; 4 mg/kg) hyperpolarized the transepithelial potential difference (V(t)) of tracheal epithelium in the isolated, perfused trachea (IPT) of the guinea pig 18 h after injection. As well, LPS increased the hyperpolarization component of the response to basolateral methacholine, and potentiated the epithelium-derived relaxing...

Bufadienolides are cytotoxic drugs that may form the basis for anticancer agents. Due to structural and functional similarity to cardiotonic glycosides, application is restricted. We, therefore, investigated correlation of their putative anticancer effects with inhibition of Na+,K+pumps. The natural bufalin and three derivatives were tested. The anticancer effects of the drugs were checked by o...

Ouabain, a specific inhibitor of the Na /K -pump, has previously been shown to interfere with intercellular communication. Here we test the hypothesis that the communication between vascular smooth muscle cells is regulated through an interaction between the Na /K -pump and the Na /Ca -exchanger leading to an increase in the intracellular calcium concentration ([Ca ]i) in discrete areas near th...

The cellular events during the initiation and maintenance of ventricular fibrillation (VF) are poorly understood. We developed a nonischemic, isolated, perfused rabbit Langendorff preparation in which sustained VF could be induced by alternating current (AC) and which allowed changes in perfusate composition. We also used Na+-K+ pump inhibition (10 ,uM ouabain or K'-free perfusate) to induce VF...

Transepithelial K(+) movement was studied in vitro in the short-circuited turtle bladder by increasing luminal K(+) permeability and by inhibiting the basolateral Na/K pump. Luminal addition of amphotericin B caused net K(+) secretion (180+/-52 nmol/h) compared with net K(+) absorption (42+/-6 nmol/h) in control bladders. Serosal ouabain and luminal amiloride abolished K(+) secretion in amphote...

The whole-cell patch-clamp technique was used to voltage clamp acutely isolated myocytes at -60 mV and study effects of ionic environment on Na/K pump activity. In quiescent guinea pig myocytes, normal intracellular Na+ is approximately 6 mM, which gives a total pump current of 0.25 +/- 0.09 pA/pF, and an inward background sodium current of 0.75 +/- 0.26 pA/pF. The average capacitance of a cell...

To evaluate the effects of glucocorticoids on the Na-K pump in human subjects, were evaluated the intracellular sodium and potassium, 42K influx across and the [3H]ouabain binding to cell membranes of intact human erythrocytes from a group of subjects taking glucocorticoids and a group of normal subjects. Intracellular sodium concentration was lower (7.2 +/- 0.4 vs. 10.9 +/- 0.2 mmol/liter cell...

Arthropod photoreceptors are polarized cells displaying distinct surface domains. The distribution of the Na,K-ATPase (sodium pump) over these domains was examined in the honeybee photoreceptor using a monoclonal antibody that specifically recognizes the sodium pump alpha-subunit (approximately 100 kDa). We find that the sodium pump is restricted to sites of the nonreceptive photoreceptor surfa...

1. Abstract 2. Introduction 3. Sodium Regulation in Uncomplicated Pregnancy 4. Sodium Regulation in Preeclampsia 5. Cell Sodium Regulation in Uncomplicated Pregnancy 5.1. Cell Sodium and Cell (Na,K)ATPase or Sodium Pump (SP) in Uncomplicated Pregnancy 5.2. Other Cell Sodium Transport Systems in Uncomplicated Pregnancy 6. Cell Sodium Regulation in Preeclampsia 6.1. Cell Sodium and Potassium in P...