The slowing of Ca2+ signals by Ca2+ indicators in cardiac muscle.
The use of high-affinity fluorescent probes for monitoring intracellular free Ca2+ in cardiac muscle is now widespread. We have investigated the consequences of introducing intracellular buffers with the properties of Fura-2 or Indo-1 on the action potential, Ca2+ transient and contractile activity of the myocardium. Our theoretical results suggest that, at the high intracellular concentrations of these fluorescent probes used on occasion to improve the signal-to-noise ratio of the emitted fluorescence, modulation of action potential profile and attenuation of the amplitudes of the Ca2+ transient and contraction can occur, together with subtle changes in the kinetics of these events.
University Laboratory of Physiology, Oxford, U.K.
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D
Noble
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T
Powell
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007211:Indoles; D007424:Intracellular Fluid / Q000378:metabolism; D007700:Kinetics; D009200:Myocardial Contraction / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*
D005456:Fluorescent Dyes; D007211:Indoles; C048960:indo-1; D002118:Calcium; D016257:Fura-2