Excitation-contraction uncoupling during ischemia in the blood perfused dog heart.
The bioluminescent of Ca(2+)-indicator, aequorin, was loaded into the left ventricular apex of blood-perfused hearts from 13 dogs for simultaneous recording of left ventricular pressure and intracellular calcium levels. During a 2 minute period of ischemia, systolic and diastolic pressures significantly decreased. In contrast, these pressure changes were associated with an increase in both systolic and diastolic calcium reaching a maximum diastolic value of 0.59 microM and a systolic value of 1.11 microM. This apparent dissociation between pressure and [Ca2+]i supports the hypothesis that changes in myofilament Ca2+ responsiveness are of major importance in modulating contractility during ischemia in large mammalian hearts.
Levine
M J
MJ
Charles A. Dana Research Institute, Boston, MA.
Harada
K
K
Meuse
A J
AJ
Watanabe
J
J
Breall
J
J
Carrozza
J P
JP
Bentivegna
L
L
Franklin
A
A
Johnson
R G
RG
Grossman
W
W
D000331:Aequorin; D000818:Animals; D001794:Blood Pressure; D002118:Calcium / Q000378:metabolism*; D003327:Coronary Disease / Q000503:physiopathology*; D004285:Dogs; D006321:Heart / Q000502:physiology* / Q000503:physiopathology; D066298:In Vitro Techniques; D007700:Kinetics; D009200:Myocardial Contraction; D010477:Perfusion
D000331:Aequorin; D002118:Calcium