Search results for "Potassium"

Arachidonic acid relaxes human pulmonary arteries through K+ channels and nitric oxide pathways.

2004

We aimed to investigate the role of K(+) channels and nitric oxide (NO) on the relaxant effects of arachidonic acid in the human intralobar pulmonary arteries. Arachidonic acid produced a concentration-dependent relaxation (E(max)=93+/-3% of maximal relaxation induced by papaverine 0.1 mM;-log EC(30)=7.03+/-0.09) that was antagonized by the cyclooxygenase inhibitor indomethacin (1 microM), by the combination of cyclooxygenase blockade and cytochrome P450 (CYP) blockade with 17-octadecynoic acid (17-ODYA, 10 microM), by the combination of cyclooxygenase inhibition and NO synthase (NOS) inhibition with N(omega)-nitro-l-arginine (l-NOARG, 100 microM), by the simultaneous inhibition of CYP and …

Effects of bupivacaine on human erythrocytes submitted to stress and evidence for an interaction between bupivacaine and flumazenil

1999

Aims To examine the effects of bupivacaine on erythrocytes submitted to an oxidative stress (AAPH) and to provide evidence for an in vitro interaction between bupivacaine and flumazenil. Methods Human erythrocytes were studied with or without AAPH in the presence of different concentrations of bupivacaine (0.15, 0.3, 0.9 and 1.8 mmol l−1 ), or flumazenil (0.16 mmol l−1 ) and with the association of flumazenil and two doses of bupivacaine (0.15 and 0.3 mmol l−1 ). Potassium efflux was measured by flame photometry at t0, and every 30 min for 2 h. Results In the absence of AAPH, extracellular potassium remained unchanged. Oxidative stress induced a significant increase in extracellular potassi…

The ionic dependence of calcium efflux from guinea pig auricles.

1968

Effects of the prostanoid EP3 -receptor agonists M&B 28767 and GR 63799X on infarct size caused by regional myocardial ischaemia in the anaesthet…

1999

1. This study investigates the effects of two agonists of the prostanoid EP3-receptor (MB PEEP: 1-2 mmHg) and subjected to occlusion of the left anterior descending coronary artery (LAD, for 7.5, 15, 25, 35, 45 or 60 min) followed by reperfusion (2 h). Infarct size was determined by staining of viable myocardium with a tetrazolium stain (NBT), histological evaluation by light and electron microscopy and determination of the plasma levels of cardiac troponin T. 3. MB saline-control, n=8) to 39+/-6 and 38+/-4% of the area at risk, without causing a significant fall in blood pressure. Pretreatment of rats with 5-hydroxydecanoate (5-HD), an inhibitor of ATP-sensitive potassium channels, attenua…

Der erythrocytäre Magnesiumstoffwechsel bei intakter und kälteinhibierter Glykolyse

1962

Continuation of glycolysis in human erythrocytes by incubation of heparinized whole blood at 37°C is followed by a decrease in the Mg-content of red cells. On inhibition of glycolysis by cold (4°C), the Mg-content of erythrocytes remains unaltered or, often, slightly increases. These actions are in clear contrast to the behaviour of potassium ions under the same conditions.

In vivo hypotensive activity ofPistacia lentiscus L

1988

The present studies were undertaken to explain the mechanism of action of the hypothesive effect of Pistacia lentiscus L. aqueous extract. The potassium, calcium and magnesium content of the aqueous extract was determined and synthetic mixtures of salts evaluated in rats. The urinary excretion volume and the sodium and potassium concentrations in urine were also determined. In an effort to explain the effects of the extract, in vivo pharmacological experiments were conducted.

Efecto in vitro de la adición de resinas de intercambio iónico sobre la biodisponibilidad de electrolitos en fórmulas de nutrición enteral artificial

2008

The in vitro effect of the addition of ion exchange resins on the bioavailability of electrolytes in artificial enteral feeding formulas Objective: To determine in vitro free ion concentration in three standard artificial enteral feeding formulas following the addition of ion exchange resins. Method: Three standard types of AEF were chosen: Osmolite HN®, Nutrison Standard® and Isosource Standard®. The ion exchange resins used were: Sodium Polystyrene Sulfonate and Calcium Polystyrene Sulfonate. 100 ml of AEF were mixed in a beaker with 1.5 g or 3 g of ion exchange resins for 48 hours at 37oC. Subsequently, the samples were precipitated and the supernatant obtained was used for determining t…

Über den Chemismus von Zustandsänderungen des Aktomyosins

1950

(1) By means of a simple method the conditions were investigated for contraction and relaxation of actomyosin (AM) under the influence of potassium, magnesium, and calcium ions, of adenosintriphosphate (ATP) or muscle-adenylic-acid and phosphocreatin.

Die diuretische Wirkung von Oxytocin beim Hund

1959

The influence of a synthetic oxytocin preparation and of prednisolone hemisuccinate on the renal excretions of water, sodium, potassium and chloride and on the clearance of endogenous true creatinine was studied in 18 dogs anesthetized with hexobarbital and barbital. The animals were deprived of food and water for 12 hours before the experiments.

Action of tertiary phenylalkylamines on cardiac transient outward current from outside the cell membrane.

1996

The effects of the phenylalkylamines verapamil (V), gallopamil (G), and devapamil (D) and their corresponding quaternary derivatives on the transient outward current (Ito) were examined in rat ventricular cardiomyocytes using the whole-cell patch-clamp technique. The question was addressed, whether phenylalkylamines act on Ito from the inside or the outside or from both sides of the cell membrane. To this end, the myocytes were either superfused extracellularly or perfused intracellularly with drug-containing solutions. In addition, the effects of verapamil were investigated at different pH-values. V, G, and D (30 microM each), applied extracellularly, reduced the steady state current of It…