TY - JOUR
T1 - Cellular calcium fluctuations in mammalian heart
T2 - Direct evidence from noise analysis of aequorin signals in Purkinje fibers
AU - Wier, W. G.
AU - Kort, A. A.
AU - Stern, M. D.
AU - Lakatta, E. G.
AU - Marban, E.
PY - 1983
Y1 - 1983
N2 - Indirect evidence suggests that fluctuations, or oscillations, in the intracellular free calcium concentrations ([Ca2+](i)) can occur spontaneously in intact cardiac preparations, but such [Ca2+](i) fluctuations have never been demonstrated directly. We used the bioluminescent Ca2+-sensitive protein aequorin to detect fluctuations in the [Ca2+](i) in canine cardiac Purkinje fibers. Noise analysis of the aequorin luminescence reveals prominent peaks of power density at frequencies of 1-4 Hz; these peaks become larger and shift to higher frequencies as the [Ca2+](i) increases. Caffeine and ryanodine abolish the [Ca2+](i) fluctuations, suggesting that Ca2+ release and uptake by the sarcoplasmic reticulum generate these events. When [Ca2+](i) fluctuations are present, less tension is produced at any given level of mean aequorin luminescence. Thus, [Ca2+](i) fluctuations will undermine attempts to relate [Ca2+](i) and force in intact myocardium.
AB - Indirect evidence suggests that fluctuations, or oscillations, in the intracellular free calcium concentrations ([Ca2+](i)) can occur spontaneously in intact cardiac preparations, but such [Ca2+](i) fluctuations have never been demonstrated directly. We used the bioluminescent Ca2+-sensitive protein aequorin to detect fluctuations in the [Ca2+](i) in canine cardiac Purkinje fibers. Noise analysis of the aequorin luminescence reveals prominent peaks of power density at frequencies of 1-4 Hz; these peaks become larger and shift to higher frequencies as the [Ca2+](i) increases. Caffeine and ryanodine abolish the [Ca2+](i) fluctuations, suggesting that Ca2+ release and uptake by the sarcoplasmic reticulum generate these events. When [Ca2+](i) fluctuations are present, less tension is produced at any given level of mean aequorin luminescence. Thus, [Ca2+](i) fluctuations will undermine attempts to relate [Ca2+](i) and force in intact myocardium.
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U2 - 10.1073/pnas.80.23.7367
DO - 10.1073/pnas.80.23.7367
M3 - Article
C2 - 6580652
AN - SCOPUS:0021014678
VL - 80
SP - 7367
EP - 7371
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 23 I
ER -