[A method of calculating the liposome membrane permeability using dialysis method]. / Sposob rascheta pronitsaemosti liposomal'noi membrany, opredeliaemoimetodom dializa.

A correct mode of calculating liposome membrane permeability determined with dialysis is proposed. The liposome membrane permeability is calculated with regard for the ion passage through two diffusion barriers: liposomal membrane and cellophane membrane. The asymmetrical ion distribution under equilibrium conditions is shown. The asymmetry is due to the formation of unstirred layers near the membrane. The equilibrium ion concentration in unstirred layers and the measured average bulk concentration in solution are different. The formula for calculating liposome membrane permeability that takes the mentioned factors into account is suggested.

[Ouabain-insensitive K+ and Na+ fluxes in frog muscle]. / Uabain-nechuvstvitel'nye potoki K+ i Na+ v myshtsakh liagushki.

Potassium and sodium fluxes in frog muscles incubated in K- and Na-free Mg2+ or choline-substituted Ringer solution were studied. Ouabain (10(-4) M) increased the potassium and decreased the sodium efflux. It was shown, that the increase of the potassium efflux was not due to changes in membrane electrical properties of inhibition of "back pumping" of potassium ions leaking out of the cells. It is supposed that potassium ions are translocated by K-carrier phosphorylated with inorganic phosphate. As known, ouabain accelerates this type of phosphorylation, that is why the potassium efflux increases. In a medium with or without ouabain sodium ions are translocated by Na-ATPase without participation of external potassium ions. Thus sodium and potassium fluxes carried out by membrane ATPase systems are not coupled.

[Temperature characteristics of ouabain-insensitive sodium flux in frog muscle]. / Temperaturnaia kharakteristika uabain-nechuvstveitel'nogo potoka natriia v myshtse liagushki.

Temperature influence on ouabain-insensitive non-diffusion sodium efflux from the frog skeletal muscle loaded by sodium was studied. It is puzzling that the up-gradient sodium efflux supplied by enzymatic reaction is characterized by low temperature coefficient (Q10 = 1.3). This contradiction was overcome by an introduction of diffusion channel in the sodium transport scheme. It is supposed that the enzymatic reaction occurs at inner membrane boundary and the sodium ion is translocated into the channel. Afterwards the sodium ions come out by diffusion. According to our calculation the energy needed for the ion translocation approximately 13 kkal/mol and its value does not depend on temperature. But temperature affects the sodium diffusion through the channel and thus the low temperature coefficient of sodium extrusion is explained.

[Relation between ouabain-insensitive differential sodium flux and sodium concentrations in solution]. / Zavisimost' nechuvstvitel'nykh k uabainu raznostnykh potokov natriia ot kontsentratsii Na v rastvore.

The dependence of net sodium ion flux on the external sodium concentration was studied under the inhibition of the sodium pump. A steady state balance of sodium ion fluxes occurred at external sodium concentration differing from the calculated one, therefore the existence of a non-diffusion component of sodium ion flux was evident. It was shown that the non-diffusion ouabain-insensitive sodium ion flux consisted of the sodium efflux not connected with chlorine efflux or potassium influx, and the sodium influx connected, perhaps, with potassium efflux.

[Relationship between unidirectional sodium ion currents and their concentration in muscle and medium]. / Zavisimost' odnonapravlennykh potokov ionov natriia ot ikh soderzhaniia v myshtse i srede.

Sodium fluxes were measured as concentrations of external sodium and intracellular sodium were changed under K-free condition. Paired sartorious muscles with high intracellular sodium concentration from frog (Rana ridibunda) were used throughout this investigation. The measured uptake of 22Na (mM/kg . h) is directly proportional to intracellular sodium but when influx of 22Na is calculated per unit surface (pmole/cm2s) taking account of "effect of relation volume/surface" the influx is to be independent of Nain. Sodium influx varied linearly with changing external Na. Sodium efflux is not dependent on external sodium concentration. The results are in favour of the conclusion that the sodium fluxes across the skeletal muscle membrane do not exhibit the mechanism of sodium--sodium exchange.

[Electrogenesis in a model of "boundary transport" in the sodium pump]. / Elektrogenez v modeli "granichnogo perenosa" natrievogo nasosa

An equation of the membrane potential (MP) was developed for a model of sodium pump when it was assumed that a macromolecule-carrier operated on the interior boundary of the membrane exchaning Na+i for K+ of membrane. These ions then moved downhill the electrochemical gradient inside the membrane. There are factors in the equation which indicate energetical consumtions for the ionic exchange. In was shown that an exchange of 3Na+ for 2K+ required 9,0 kkal/mole. The equation satisfactorily describes experimental values of MP during the electrogenic active transport. After all it was shown that an alteration of MP for 100 mV did not affect the operation of sodium pump i.e. the influence of outer electrical field was not detected.