English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Dear Sir: With ion-selective microelectrodes, it is possible to measure intracellular ion activities and calculate transmembrane electrochemical potential differences . Recently, these techniques have been carefully applied to the measurement of Na and Ca ion activities in mammalian ventricular and Purkinje fibers (Sheu and Fozzard, 1982). The results show that under a wide variety of circumstances the ratio of the electrochemical gradients for Na andCa remains remarkably constant near a value of 2.5 . It is reasonable under certain conditions to expect that this ratio represents the stoichiometric coefficient of the Na/Ca exchange . Nonetheless, we wish to point out certain difficulties inherent in the derivation of the exchange stoichiometry from such measurements . In addition, we wish to discuss Sheu and Fozzard's intriguing observation that the ratio increases to ^-3 when the Na pump is inhibited . We hypothesize that exchange may be represented by the following transmembrane reaction :

the journal of general physiology/the journal of general physiology

Electrochemical ion gradients and the Na/Ca exchange stoichiometry. Measurements of these gradients are thermodynamically consistent with a stoichiometric coefficient greater than or equal to 3.