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We have studied the effect of hypoxia and ouabain on the muscle resting potential (RP) of the cockroach Periplaneta americana L. The experiments were done in insects reared either in normoxic or hypoxic conditions and treated, or not treated, with ouabain. Hypoxic conditions decreased the RP by
The effects of hypoxia and reoxygenation on the inotropic effect of ouabain and sodium pump were studied in the isolated, arterially perfused newborn rabbit heart. Myocardial 86Rb+ active uptake was used as a marker of the sodium pump activity. During reoxygenation after mild hypoxia, 86Rb+ active
The effect of cardiac glycosides on myocardial function during hypoxia is controversial. Accordingly, we studied left ventricular performance during hypoxia and reoxygenation in the presence of a mildly inotropic, nontoxic dose of ouabain using isolated, isovolumic, buffer-perfused rabbit hearts.
Effects of hypoxia and ouabain on transcapillary exchange of [99mTc]hexakis (2-methoxyisobutylisonitrile) [SESTAMIBI, also known as MIBI or HEXAMIBI] and 201TI were investigated with indicator-dilution studies using isolated rabbit hearts. Peak myocardial extraction (Emax), permeability-surface area
In the present investigation, electron probe X-ray microanalysis was used to characterize the effects of in vitro ouabain (2 mM) or anoxia on elemental composition (e.g. Na, K, Ca) and water content of rat peripheral (tibial) nerve myelinated axons and Schwann cells. Results showed that independent
The effects of hypoxia on the transmembrane potential of dog Purkinje cells in isolated, superfused fiber bundles pretreated with ouabain were studied. Cells stimulated electrically at 93/min were exposed to ouabain, 2.1 X 10(-7) M, until the magnitude of phase 4 depolarization increased to 7-12 mV.
This study investigates the effect of hypoxia on the high affinity strophanthidin/ouabain binding site of brain cell membrane Na+,K(+)-ATPase in 30, 45 and 60 day (term) fetal guinea pigs. Studies were performed on 30 fetuses randomized to either normoxic or hypoxic conditions. The hypoxic fetuses
The influence on the cardiac stimulation threshold of changes in the myocardial intra/extracellular potassium ratio induced with ouabain and hypoxia was investigated in 9 dogs with total atrioventricular block. In spite of significant elevations of extracellular potassium and reductions of
Simple and reliable in vitro models of cerebral ischaemia are important for the identification of antiischaemic/antihypoxic compounds. Alterations of the concentrations of potassium and calcium were recorded in slices of hippocampus of the rat. The slices were subjected to hypoxia in the presence
Digoxin and ouabain are cardioactive glycosides, which inhibit the Na+/K+-ATPase pump and in this way they increase the intracellular concentration of cytosolic calcium ([Ca2+](i)). They are also strong inducers of the P-glycoprotein (Pgp), a transmembrane transporter which extrudes several drugs,
Hypoxia is suggested to increase intracellular Ca2+, thereby affecting cellular functions. If this is the case, the effect would be modified by other treatments which also elevate intracellular levels of Ca2+. To test this possibility, in mouse diaphragm preparations, the effects of hypoxia were
1. The 60 mM K+, 152 mM K+, Na-deficient medium and oubain-induced contractions of aorta were not so affected by severe hypoxia. 2. The 60 mM K+, 152 mM K+, Na(+)-deficient medium-induced responses were greatly reduced by deprivation of external Ca2+ in normoxia. 3. As the concentration of