Cd2+ effects on respiration and swelling of rat liver mitochondria were modified by monovalent cations.

Changes in Cd2+ effects on respiration of succinate-energized rat liver mitochondria were studied after replacement of 100 mM KCl in an incubation medium by equimolar amounts of NaCl or LiCl, or by 200 mM sucrose. In KCl medium, 2.5-10 microM Cd2+ decreased the state 3 and 2,4-dinitrophenol (DNP)-stimulated respiration of mitochondria, and increased their respiration in the state 4, however, 10-40 microM Cd2+ diminished the state 4 respiration.

Cuprous ions activate glibenclamide-sensitive potassium channel in liver mitochondria.

Cuprous ions at micromolar concentrations induced swelling of rat liver mitochondria in isotonic solutions of potassium thiocyanate and potassium acetate. The swelling in K-acetate in the presence of the protonophore [corrected] carbonyl cyanide m-chloropenylhydrazone was partly inhibited by glibenclamide. In K(+)-containing media, Cu+ collapsed the mitochondrial membrane potential formed by operation of the respiratory chain with succinate or tetramethyl p-phenylenediamine + ascorbate as substrates or by the proton-pumping ATPase.

[The effect of Cd2+ on the respiration and swelling of isolated rat liver mitochondria in incubation media of different compositions].

We studied a change in Cd2+ influence on state 4 and 3 respiration and on 2,4-dinitrophenol (DNP)-stimulated respiration of isolated rat liver mitochondria, after replacement of KCl for equimolar quantities of NaCl, LiCl or for 200 mM sucrose in the incubation medium. Cd2+ concentrations higher than 2.5 microM reduced state 3 respiration or DNP-stimulated one in KCl medium (control), and activated state 4 respiration, however, at Cd2+ concentrations higher than 12.

[Changes in the effect of Cd2+ on the respiration of isolated rat liver mitochondria after their preincubation with Ca2+, Sr2+, Ba2+, Mn2+ and ruthenium red].

Action of Cd+ on mitochondrial respiration is decreased by some bivalent ions, however the reason of this still remains obscure. Change of Cd2+ action over a wide range of its concentrations on respiration of rat liver mitochondria in states 4, 3 and in the presence of 2, 4-dinitrophenol (DNP) after mitochondrial preincubation with Ca2+, Sr2+, Ba2+, Mn2+ or ruthenium Red (RR) was studied in vitro. In the control (experiments without preincubation), Cd2+ lowers mitochondrial respiration in state 3 as well as that in the presence of DNP, and increases the respiration in state 4.

Anion-dependent transport of thallous ions through human erythrocyte membrane.

Undirectional fluxes of 204Tl+ through the human red blood cell membrane were measured. The inward rate coefficient measured in a K(+)-free saline was 15.6 +/- 0.

Highly selective blockade of the frog skin sodium channels by monovalent copper cations.

.5 mM Cu+ added to the mucosal side of frog skin caused rapid reversible inhibition of short-circuit current while no effect of Cu+ could be observed at the serosal side. In both cases Cu2+ was reduced to Cu+ by adding 10 mM ascorbic acid.

Potassium transport in lamprey (Lampetra fluviatilis) erythrocytes: evidence for K+ channels.

1. Unidirectional K+ (86Rb) influx in lamprey red blood cells was studied under different conditions. 2.

Cadmium as a tool for studying calcium-dependent cation permeability of the human red blood cell membrane.

Three Ca(2+)-dependent procedures known to increase cation permeability of red blood cell membranes were tested with Cd2+ ions which equal Ca2+ ions both in their charge and the crystal radius, 1. Increase of non-selective permeability for monovalent cations by incubating the red cells in a Ca(2+)-free sucrose medium. Addition of Cd2+ to the suspension of leaky cells failed to restore the initial impermeability of the red cell membrane while a repairing effect of Ca2+ was evident both in the presence and absence of Cd2+.

Interaction of Cu+ with mitochondria.

The uptake of Cu+ by rat liver mitochondria is rapid and extensive. Respiration is stimulated by 10 microM Cu+ then inhibited and the inhibition could not be relieved with uncoupling agents. Collapse of the membrane potential is induced by 5-10 microM Cu+.

[The effect of anoxia and energy metabolism inhibitors on potassium and sodium homeostasis in the neurons of the gastropod mollusk].

Anoxia and inhibitors of energy metabolism have been studied for their effect on intracellular K and Na concentrations, membrane potential, conductivity, passive and active ouabain-sensitive transport of potassium (86Rb) in neurons of freshwater snail Planorbarius corneus. The X-ray microanalysis has shown that anoxia caused no changes in K and Na concentrations in neurons. NaCN inhibited oxygen uptake by ganglia, but has actually no effect on the membrane potential, conductivity and 86Rb uptake in neurons.

[The isomorphism of univalent thallium and potassium in membrane transport processes].

Thallium ions (T1+) are able to isomorphous replacement of K+ in various minerals. The similarity between. T1+ and K+ is based upon the closeness of their crystal radii, hydration energy and mobility in aqueous solutions.

Thallium and rubidium permeability of human and rat erythrocyte membrane.

Transport of Tl+ and Rb+ in human and rat erythrocytes was investigated in the presence of ouabain. The chloride-dependent cotransport of Tl+, Rb+ and Na+ was precluded by replacement of Cl- by NO3-. The inward and outward rate constants for the residual fluxes of the cations were determined by measuring the transport of 204Tl and 86Rb in double label experiments.

[The transport of univalent thallium across the human erythrocyte membrane].

Transport of 204Tl was studied in human erythrocytes incubated in isotonic salt solutions at pH 7.4 and 37 degrees C. 204Tl was rapidly accumulated in cells up to the constant level within a 10 minutes incubation (t0.

[Effect of sodium, lithium and amiloride on the K+-dependent phosphatase activity of membrane preparations of Na,K-ATPase].

Effects of sodium, lithium and amiloride on the ATPase reaction and on its potassium-dependent step were studied using membrane preparations of Na,K-ATPase. It was established that the addition of 70 mM NaCl or LiCl to the reaction medium diminished the hydrolysis of para-nitrophenyl phosphate (pNPP) by 70 and 40%, respectively. Amiloride (0.

[Effect of inhibitors of energy metabolism on potassium accumulation in the neurons of the mollusk Planorbarius corneus].

Studies have been made of the effect of inhibitors of energy metabolism on maintenance of Na and K concentrations, as well as on accumulation of Rb (as an analogue of K) in single neurones of the mollusc P. corneus. Concentrations of Na, K and Rb in cells were determined by X-ray spectral microanalysis.

[Transport of univalent cations across the erythrocyte membrane of hypertensive rats of various ages].

In the erythrocytes incubated at low temperature (3-6 degrees C), the uptake of Li+ in 6- and 16-week old spontaneously hypertensive rats (SHR) was significantly higher than in the normotensive rats (WKY) of the same age. During the incubation of cells at 37 degrees C no difference occurred in either ouabain-sensitive or ouabain-resistant fluxes of Rb+, Na+ and Li+ between the 16-week old SHR and the WKY. K+ efflux from the erythrocytes at 3 degrees C was consistently stimulated after addition to the incubation medium of 1 mmol/l Ca2+.

[Effect of cadmium ions on the respiration, cation transport and morphology of the liver mitochondria in the rat and the lamprey].

The influence of Cd2+ on the function and structure of liver mitochondria of rats and lamprey (Lampetra fluviatilis L.) has been studied in vitro. It is shown that Cd2+ can penetrate into the mitochondrial matrix due to Ca2+-transport mechanism.

[Effect of energy metabolism on the ionic selectivity of the K+ center of the Na+/K+ pump in the skin of the frog].

The uptake of Rb+ and Tl+ in frog skin incubated in saline containing 86Rb and 204Tl was studied. The ratio of ouabain-sensitive influxes Tl+/Rb+ = 2. Inhibition of the unidirectional transport of Na+ by rotenone or by Tl+ was not accompanied by the total decrease in the ouabain-sensitive uptake of Rb+ and Tl+.

[Cadmium accumulation in tissues of the mussel Mytilus galloprovincialis].

Studies have been made on cadmium accumulation in tissues of mussels kept within 20-60 days in water artificially enriched by Cd up to 20-100 micrograms/l. Irrespectively of cadmium concentration in the medium, its accumulation in tissues decreases in the following order: mid-gut gland, gills, gonads, mantle, adductor. Maximum concentration of Cd was found in the digestive tubuli of the mid-gut gland by X-ray microanalysis.

[The rate of outflow of penetrating cations does not depend on the energy state of mitochondria].

Inhibiton of respiration at 0 degrees C believed to decrease the membrane potential in mitochondria did not lead to a substantial acceleration of the efflux of penetrating cations (triphenylmethylphosphonium, Cs- valinomycin). On the contrary the energy-dependent influx of the cations was rapidly inhibited indicating that there was no prolonged delay in the membrane deenergization. Low sensitivity of the cation efflux to respiration inhibition suggests under the conditions studied the metabolic component of the membrane potential to be rather small.

[Action of the salts of univalent thallium on the liver mitochondria of the rat].

Using light scattering and electron microscopic techniques, studies have been made of the swelling of liver mitochondria in isotonic sucrose solutions containing different concentrations of nitrate or acetate of monovalent thallium. It was concluded that the injurious effect of thallium on the mitochondria is associated with both its penetration into intramitochondrial space, and interaction of the external thallium with mitochondrial membranes.

Interaction between propranolol and electron donors in altering the calcium ion-dependent potassium ion-permeability of the human red blood cell membrane.

Both propranolol and the electron donors ascorbate plus phenazine methosulfate increase the K+-permeability of the red blood cell membrane. The present investigation examined whether these effects were additive. Contrary to expectations, propranolol added after electron donors sharply inhibited the K+ (86Rb) efflux induced by such donors, without forming new K4 channels analogous to those induced by propranolol in intact red blood cells.