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To investigate the volume regulatory ability of frog erythrocytes, we studied water and ion contents in the cells incubated in isosmotic (210 mOsm) and anisosmotic media. The cell volume decreased to 63% of the control in a hypertonic medium (+200 mM sucrose) and then gradually recovered to approximately 81% within 2 h. The regulatory volume increase (RVI)(More)
K+ and Na+ influx into frog erythrocytes incubated in standard saline was studied using 86Rb and 22Na as tracers. 10 microM isoproterenol (ISP) produced a significant increase in K+ influx for the first 15 min, which was sustained during the entire 60 min of cell incubation. Treatment of red cells with the phosphodiesterase (PDE) blockers theophylline(More)
Pathways of K+ movement across the erythrocyte membrane of frog Rana temporaria were studied using 86Rb as a tracer. The K+ influx was significantly blocked by 0.1 mmol·l-1 ouabain (by 30%) and 1 mmol·l-1 furosemide (by 56%) in the red cells incubated in saline at physiological K+ concentration (2.7 mmol·l-1). Ouabain and furosemide had an additive effect(More)
The paper studies several approaches to numerical integration over a domain defined implicitly by an indicator function such as the level set function. The integration methods are based on subdivision, moment–fitting, local quasi-parametrization and Monte-Carlo techniques. As an application of these techniques, the paper addresses numerical solution of(More)
The studies performed during the past decade showed that, under the conditions of Ca 2+ loading of mitochondria, the permeability transition pore (MPTP) penetrable for molecules up to 1500 kDa is formed in the inner mitochondrial membrane. It was shown that the MPTP is formed, in particular, by the voltagedependent anion channel of the inner mitochondrial(More)
Unidirectional K+ and Na+ influxes in the frog erythrocytes incubated in Cl- or NO(3)- media with 2.7 mM K+ were measured using 86Rb and 22Na as tracers. K+ influx was inhibited by 35-55% in the presence of 0.2-1.0 mM furosemide but it was unaffected by 0.1-0.2 mM bumetanide. Furosemide at a concentration of 0.5 mM had no effect on K+ loss from the frog red(More)
Neurokinin-3 receptor (NK3R) has recently emerged as important in modulating the tonic pulsatile gonadotropin-releasing hormone (GnRH) release. We therefore decided to explore NK3R antagonists as therapeutics for sex-hormone disorders that can potentially benefit from lowering GnRH pulsatility with consequent diminished levels of plasma luteinizing hormone(More)
.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. Cu+ being similar to Na+ both in charge and crystal radius (0.096 and 0.095 nm, respectively) appears to block Na+(More)
Ions of monovalent thallium are able to replace potassium ions in membrane transport processes and are a convenient marker to reveal mechanisms of transport of physiologically important ions. In various cell types the known mechanisms of thallium transport include Na,K-pump and potassium channels [1]. At the same time, in human erythrocytes, Tl+ penetrates(More)