Key result
External application of 10-4M ouabain caused an average fall of 68% in sodium efflux in barnacle muscle fibres, whereas internal application had no effect.
Why the study?
Does ouabain affect sodium efflux in barnacle muscle fibres?
Does ouabain affect sodium efflux in barnacle muscle fibres?
This basic science study demonstrates that external, but not internal, application of ouabain significantly inhibits sodium efflux in barnacle muscle fibres.
Answers are grounded in this paper and cite their sources.
No direct clinical implications in humans; leaves open external ouabain action for cardiac Na/K-ATPase research.
Measurements of radiosodium efflux were carried out on single fibres from the barnacleBalanus nubilusorB. aquila, using the micro‐injection technique. 10‐4M ouabain caused an average fall of 68% of the Na efflux, the minimal effective concentration beingca.10‐7M. Internal application of 4 × 10‐3M ouabain was without effect. Abolition of the ouabain‐sensitive component with ouabain, followed by raising the external K concentration to 30 mM, resulted in a marked rise in the residual Na efflux. Stimulation of the ouabain‐insensitive Na efflux was also seen after reducing the external pH, as well as after microinjecting CaCl2but not MgCl2. Uncoupling of the active transport system by K removal, followed by external application of ouabain, and subsequent acidification of the bathing medium, led to stimulation which was considerably greater than that taking place when the Na efflux was uncoupled by K removal and then stimulated by external acidification.
No takes yet. Share an insight, caveat, or question.
A 1973 study studied this question. Ouabain was evaluated on Sodium efflux. External application of 10-4M ouabain caused an average fall of 68% in sodium efflux in barnacle muscle fibres, whereas internal application had no effect.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: