Myocardial sarcoplasmic reticulum Ca 2+ ATPase function is increased by aerobic interval training

Abstract

Objective Reduced activity of the sarcoplasmic reticulum Ca²⁺ ATPase-2a (SERCA-2a) contributes to myocardial dysfunction. Exercise training improves myocardial Ca²⁺-handling, but SERCA-2a function is uncertain. We assessed SERCA-2a activity after exercise training.

Methods SERCA-2a function was assessed by sarcoplasmic reticulum Ca²⁺ uptake in cardiomyocytes with other Ca²⁺ uptake mechanisms blocked, in mice after aerobic interval training versus sedentary controls.

Results We established protocols to assess SERCA-2a function, and show that aerobic interval training increases the maximal rate of Ca²⁺ uptake by 30%. This is at least partly explained by reduced phospholamban-to-SERCA-2a ratio.

Conclusion Aerobic interval training improves myocardial SERCA-2a performance, explaining at least partly why myocardial Ca²⁺-handling improves after exercise training.

Keywords

calcium exercise myocardium

Get full access to this article

View all access options for this article.

References

Diffee

Seversen

Titus

MM.

Exercise training increases the Ca²⁺ sensitivity of tension in rat cardiac myocytes. J Appl Physiol 2001; 91: 309–315.

Kemi

Haram

Loennechen

Osnes

J-B

Skomedal

Wisloff

Ellingsen

Moderate versus High intensity: differential effects on aerobic fitness, cardiomyocyte contractility, and endothelial function. Cardiovasc Res 2005; 67:161–172.

Kemi

Haram

Wisloff

Ellingsen

Aerobic fitness is associated with cardiomyocyte contractile capacity and endothelial function in exercise training and detraining. Circulation 2004; 109:2897–2904.

Wisloff

Loennechen

Currie

Smith

Ellingsen

Aerobic exercise reduces cardiomyocyte hypertrophy and increases contractility, Ca²⁺ sensitivity and SERCA-2 in rat after myocardial infarction. Cardiovasc Rec 2002; 54:162–174.

Wisloff

Loennechen

Falck

Beisvag

Currie

Smith

Ellingsen

Increased contractility and calcium sensitivity in cardiac myocytes isolated from endurance trained rats. Cardiovasc Res 2001; 50:495–508.

Bers

DM.

Cardiac excitation-contraction coupling. Nature 2002; 415: 198–205.

Kemi

Ellingsen

Ceci

Grimaldi

Smith

Condorelli

Wisloff

Aerobic interval training enhances cardiomyocyte contractility and Ca²⁺ cycling by phosphorylation of CaMKII and Thr-17 of phospholamban. J Mol Cell Cardiol 2007 doi:10.1016/j.yjmcc.2007.06.013.

Kemi

Loennechen

Wisloff

Ellingsen

Intensity-controlled treadmill running in mice: cardiac and skeletal muscle hypertrophy. J Appl Physiol 2002; 93:1301–1309.

Grynkiewicz

Poenie

Tsien

RY.

A new generation of Ca²⁺ indicators with greatly improved fluorescence properties. J Biol Chem 1985; 260:3440–3450.

10.

Hoydal

Wisloff

Kemi

Britton

Koch

Smith

Ellingsen

Nitric oxide synthase type-1 modulates cardiomyocyte contractility and calcium handling: association with low intrinsic aerobic capacity. Eur J Cardiovasc Prev Rehabil 2007; 14:319–325.

11.

Teucher

Prestle

Seidler

Currie

Elliott

Reynolds

Excessive sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase expression causes increased sarcoplasmic reticulum Ca²⁺ uptake but decreases myocyte shortening. Circulation 2004; 110:3553–3559.

12.

Kargacin

Ali

Kargacin

ME.

Ruthenium red reduces the Ca²⁺ sensitivity of Ca²⁺ uptake into cardiac sarcoplasmic reticulum. Pflugers Arch 1998; 436:338–342.