/sup 3/H-ouabain binding and sodium-pump activity measured in myocytes isolated from guinea-pig heart
Because of the toxicity of millimolar ouabain, non-specific /sup 3/H-ouabain binding was assessed by monitoring the dissociation of the bound drug. Analysis of specific /sup 3/H-ouabain binding to myocytes yielded non-linear Scatchard plots. Nonlinearity appears to result from reduced /sup 3/H-ouabain binding due to low intracellular Na/sup 2/ concentration. Addition of 2 ..mu..M monensin, A Na/sup +/ ionophore, significantly increased /sup 3/H-ouabain binding. Incubation in Ca/sup 2 +/-free solution (0.25 mM EGTA) stimulated /sup 3/H-ouabain binding to a greater degree than monensin and caused Scatchard plots to have two distinct linear components. Monensin had no significant effects when /sup 3/H-ouabain binding occurred in Ca/sup 2 +/-free solution. Effects of Ca/sup 2 +/-free incubation to increase /sup 3/H-ouabain binding suggest that Ca/sup 2 +/ has a direct effect on /sup 3/H-ouabain binding. Alternatively, Ca/sup 2 +/-free incubation may increase Na/sup +/ permeability of the sarcolemma. Isoproterenol, phenylephrine, TPA (phorbol 12-myristate 13-acetate), La/sup 3 +/, and the Ca/sup 2 +/-ionophore A23187 failed to cause significant changes in /sup 3/H-ouabain binding when myocytes were incubated in a solution containing 0.5 or 2.5 ..mu..M /sup 3/H-ouabain, 0.1 mM Ca/sup 2 +/ and 1 mM K/sup +/.
- Research Organization:
- Michigan State Univ., East Lansing (USA)
- OSTI ID:
- 6401140
- Resource Relation:
- Other Information: Thesis (Ph. D)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CALCIUM COMPOUNDS
BIOLOGICAL FUNCTIONS
OUABAIN
BIOCHEMICAL REACTION KINETICS
PHORBOL ESTERS
BIOLOGICAL EFFECTS
SODIUM COMPOUNDS
MEMBRANE TRANSPORT
ANIMAL CELLS
CELL MEMBRANES
GUINEA PIGS
HEART
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
BODY
CARBOHYDRATES
CARCINOGENS
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
DRUGS
ESTERS
FUNCTIONS
GLYCOSIDES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
RODENTS
STROPHANTHINS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology
550201 - Biochemistry- Tracer Techniques