Effects of lactate on the relative contribution of Ca2+ extrusion mechanisms to relaxation in guinea-pig ventricular myocytes

The Journal of Physiology
C M Terracciano, K T Macleod

Abstract

1. The aim of this study was to investigate the effects of 20 mM extracellular lactate on Ca2+ regulation mechanisms in enzymatically isolated single guinea-pig cardiac myocytes. 2. The activities of the Ca2+ regulation mechanisms during application of lactate were studied using rapid cooling contractures (RCCs) and fast application of caffeine. Cytoplasmic Ca2+ was monitored using the fluorescent indicator indo-1. 3. After application of 20 mM lactate for 5 min, the diastolic level of Ca2+ was increased. The change in cytoplasmic Ca2+ elicited by stimulation (Ca2+ transient) was also changed. With lactate, the amplitude of the Ca2+ transient was smaller, and its time course was slower compared with control. 4. The recovery of cytoplasmic Ca2+ during rewarming after rapid cooling in lactate was slower than under control conditions. When the rewarming was performed either in Na(+)- and Ca(2+)-free solution or in the presence of 10 mM caffeine, the rate of recovery of cytoplasmic Ca2+ in lactate was slower than under control conditions, suggesting that the activity of both SR Ca2+ uptake and Na(+)-Ca2+ exchange is affected by lactate. 5. Cytoplasmic Ca2+ recovery during application of 10 mM caffeine in lactate was slower than in ...Continue Reading

Citations

May 10, 2001·Journal of Molecular and Cellular Cardiology·K DaviaS E Harding
Feb 8, 2005·The Journal of Physiology·Jens KockskämperLothar A Blatter
May 1, 2007·Biochemical and Biophysical Research Communications·Klára FarkasfalviCesare M N Terracciano
Mar 8, 2005·Pharmacological Research : the Official Journal of the Italian Pharmacological Society·Laura CominiRoberto Ferrari
Aug 17, 2005·European Journal of Pharmacology·Reginald LiewPeter Collins
Dec 22, 1999·Acta Physiologica Scandinavica·P TaviM Weckström
Dec 28, 2002·Annals of the New York Academy of Sciences·Cesare Terracciano
Jul 17, 1999·The American Journal of Physiology·P TaviM Weckström
Dec 16, 2010·Journal of Molecular and Cellular Cardiology·Vesna Nikolova-KrstevskiDiane Fatkin

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