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Acta Physiologica 2011; Volume 202, Supplement 685
Scandinavian Physiological Society's Annual Meeting
8/12/2011-8/14/2011
Bergen, Norway
RATE-DEPENDENT REGULATION OF SARCOPLASMIC RETICULUM CA2+ ATPASE IN HUMAN ATRIAL MYOCYTES
Abstract number: 8.1.9
KOIVUMAKI1 JT, TAVI1 P
1A.I. Virtanen Institute of Molecular Sciences, University of Eastern Finland, Finland; Email: [email protected]
Aims:
In mammalian cardiac myocytes, one of the most important regulators of intracellular calcium dynamics is the sarcoplasmic reticulum (SR) calcium ATPase (SERCA), which affects excitation-contraction coupling both "upstream" (action potential) and "downstream" (contractility). Accumulating evidence from ventricular myocytes suggests an important role for calcium/calmodulin dependent kinase (CaMK) II in this context (Maier and Bers 2007); however, in atrial myocytes relatively little data exists on the rate-dependent regulation of SERCA.
Methods:
Here, we implement CaMK-dependent regulation of SERCA into a recently developed mathematical model of human atrial myocyte (Koivumäki et al. 2011), to study the rate dependence of SERCA's contribution to intracellular calcium recirculation.
Results:
Results indicate that stimulation of SERCA function, at high heart rates, promotes a substantial increase in SR calcium content and cytosolic calcium transient amplitude. Also, faster pacing shifts the balance of NCX vs. SERCA in calcium removal from cytosol during diastole.
Conclusion:
We conclude that CaMK-mediated stimulation of SERCA function is an important modulator of excitation-contraction coupling and rate dependence of action potential duration in atrial myocytes.
References:
Koivum¨aki, J.T., Korhonen, T., Tavi, P. 2011. PLoS Comput Biol 7(1): e1001067. Maier, L.S., Bers, D.M. 2007 Cardiovasc Res 73, 631640.
To cite this abstract, please use the following information:
Acta Physiologica 2011; Volume 202, Supplement 685 :8.1.9