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Title: Measurement and Modeling of Ca2+ waves in isolated rabbit ventricular cardiomyocytes
Authors: Macquaide, Niall ×
Dempster, J
Smith, G. L #
Issue Date: Oct-2007
Publisher: Biophysical soc
Series Title: Biophysical journal vol:93 issue:7 pages:2581-2595
Abstract: The time course and magnitude of the Ca2+ fluxes underlying spontaneous Ca2+ waves in single permeabilized ventricular cardiomyocytes were derived from confocal Fluo-5F fluorescence signals. Peak. ux rates via the sarcoplasmic reticulum (SR) release channel (RyR2) and the SR Ca2+ ATPase (SERCA) were not constant across a range of cellular [Ca2+] values. The Ca2+ affinity (K-mf) and maximum turnover rate (V-max) of SERCA and the peak permeability of the RyR2-mediated Ca2+ release pathway increased at higher cellular [Ca2+] loads. This information was used to create a computational model of the Ca2+ wave, which predicted the time course and frequency dependence of Ca2+ waves over a range of cellular Ca 21 loads. Incubation of cardiomyocytes with the Ca2+ calmodulin (CaM) kinase inhibitor autocamtide-2-related inhibitory peptide (300 nM, 30 mins) significantly reduced the frequency of the Ca2+ waves at high Ca2+ loads. Analysis of the Ca2+ fluxes suggests that inhibition of CaM kinase prevented the increases in SERCA Vmax and peak RyR2 release. ux observed at high cellular [ Ca 21]. These data support the view that modi. cation of activity of SERCA and RyR2 via a CaM kinase sensitive process occurs at higher cellular Ca2+ loads to increase the maximum frequency of spontaneous Ca2+ waves.
URI: 
ISSN: 0006-3495
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Experimental Cardiology
× corresponding author
# (joint) last author

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