Inhibition of the electrogenic Na,K pump and Na,K-ATPase activity by tetraethylammonium, tetrabutylammonium, and apamin
Language English Country United States Media print
Document type Journal Article
PubMed
2838645
DOI
10.1002/jnr.490190414
Knihovny.cz E-resources
- MeSH
- Apamin pharmacology MeSH
- Diaphragm drug effects metabolism MeSH
- Potassium metabolism MeSH
- Quaternary Ammonium Compounds pharmacology MeSH
- Membrane Potentials drug effects MeSH
- Microsomes drug effects metabolism MeSH
- Brain drug effects metabolism MeSH
- Mice MeSH
- Ouabain metabolism MeSH
- Sodium metabolism MeSH
- Sodium-Potassium-Exchanging ATPase metabolism MeSH
- Tetraethylammonium Compounds pharmacology MeSH
- Bee Venoms pharmacology MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Apamin MeSH
- Potassium MeSH
- Quaternary Ammonium Compounds MeSH
- Ouabain MeSH
- Sodium MeSH
- Sodium-Potassium-Exchanging ATPase MeSH
- tetrabutylammonium MeSH Browser
- Tetraethylammonium Compounds MeSH
- Bee Venoms MeSH
The K+-induced hyperpolarization of Na-loaded mouse diaphragm muscle, enzymatic activity of Na,K-ATPase and 3H-ouabain binding to rat brain microsomes was measured in the presence of K+ channel blockers tetraethylammonium (TEA), tetrabutylammonium (TBA) and apamin. TBA, and to a lesser extent TEA in millimolar concentrations, inhibited the electrogenic effect of the Na,K pump, Na,K-ATPase activity, and 3H-ouabain binding. The inhibition of 3H-ouabain binding by TEA or TBA was more evident in the presence of ATP and Na+ ions. Apamin in nanomolar concentrations inhibited the electrogenic effect of Na,K pump and Na,K-ATPase but not the 3H-ouabain binding. The hyperpolarizing effects of insulin and NADH, but not that of noradrenaline, were also prevented by apamin. The inhibition of Na,K pump by TEA and TBA is apparently due to both competition with K+ for a binding site on the Na,K-ATPase and a reduction in the number of transporting sites. The site of action of apamin on Na,K-ATPase is different from that of tetra-alkylammonium compounds; it apparently decreases the turnover rate of the enzyme.
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