PMID: 2443663Mar 1, 1987Paper

Factors affecting intracellular sodium during repetitive activity in isolated sheep Purkinje fibres

The Journal of Physiology
M R BoyettA J Levi

Abstract

1. Intracellular Na+ activity (aiNa) was measured using neutral-carrier Na+-sensitive micro-electrodes in voltage-clamped sheep Purkinje fibres during and after 4 min sequences of depolarizing pulses applied to around 0 mV, at a rate of 2.5 Hz. After trains of pulse duration 50 ms the mean increase in aiNa was 0.65 +/- 0.3 mM (mean +/- S.D., n = 18) whereas with longer pulse durations this rise became progressively smaller. At pulse durations of 300 ms a fall in aiNa was usually found. 2. Recovery of aiNa after a pulse sequence followed a roughly exponential time course. The half-time of decline after a rise in aiNa using 50 ms pulses was 111 +/- 52 s (n = 10), compared with a half-time of 318 +/- 116 s (n = 6) for recovery from a fall in aiNa during a sequence of 300 ms pulses. 3. Application of 2 mM-Cs+ to block the pace-maker current (if) resulted in a decrease in resting aiNa by 0.85 +/- 0.45 mM (n = 6) and an outward current shift. Na+ loading during a depolarizing pulse train was greater in 2 mM-Cs+ than in control solution. The rise in aiNa produced by a train of 50 ms pulses in Cs+ was 1.15 +/- 0.4 mM (n = 10). At short pulse durations in the presence of Cs+, Na+ loading at the end of a pulse train increased as a functi...Continue Reading

Citations

Jun 1, 1995·Pflügers Archiv : European journal of physiology·J P Chamunorwa, S C O'Neill
Dec 1, 1994·Journal of Biomedical Science·P. Abete, M. Vassalle
Feb 7, 1992·Journal of Theoretical Biology·D R LemieuxD Joly
May 7, 1988·Journal of Theoretical Biology·M R Boyett, D Fedida
Jul 1, 1988·American Heart Journal·H A Fozzard
Oct 1, 1987·Pflügers Archiv : European journal of physiology·M R Boyett, A J Levi
May 1, 1997·Journal of Cardiovascular Pharmacology·S M LaskerR P Kline
Jun 1, 1997·Journal of Cardiovascular Electrophysiology·A J LeviJ V Jones
Jul 25, 2019·Nature Communications·Pessah YampolskyPatrick A Schweizer
Jan 1, 1987·Progress in Biophysics and Molecular Biology·B Lewartowski, B Pytkowski
Apr 1, 1990·The American Journal of Physiology·S W ChaeC O Lee

❮ Previous
Next ❯

Related Concepts

Related Feeds

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.