The First International Scientific Teleconference
"Cardiovascular Surgery and Angiology - 2003"
Vasiliev A.N., Kravtsova V.V., Prokofiev A.V., Vaschinkina E.V., Krivoi I.I.
Physiological model for cardiac glycosides testing:specific inhibitors of a2-isoformЕ Na,K-TPase
Saint-Petersburg State University
Saint-Petersburg, Russia
The experiments were made on isolated preparations of rat diaphragm (which express a1- and a2-isoform of Na,K-ATPase) and purified Na,K-ATPase from lamb kidney (a1-isoform). It has been found that acetylcholine (100 nM) does not affect the activity of kidney Na,K-ATPase. However, in rat skeletal muscle fibers it increases electrogenic component of resting membrane potential due to an activation of a2-isoform of the Na,K-ATPase. In the presence of 100 nM acetylcholine efficacy of ouabain which inhibits a2-isoform electrogenic component increases by an order of magnitude (~10 nM). This method is considered to be convenient physiological assay for testing cardiac glycosides which selectively inhibit a2-isoform of the Na,K-ATPase a major regulator of calcium balance in cardiac muscle.
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