Jonathan A. W. Stecyk1, Christian Bock2, Johannes Overgaard3, Tobias Wang3, Anthony P. Farrell1, Hans O. Prtner2
1University of British Columbia, Vancouver, BC, Canada; 2Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany; 3University of Aarhus, Aarhus, Denmark
The freshwater turtle Trachemys scrypta can tolerate anoxia for months in the cold, making it an ideal animal model for studies of cardiac energetics. Here, we used in vivo 31P-NMR to investigate the coupling between cardiac energetics and cardiac performance during anoxia at 21C and 5C. During anoxia high energy phosphates and intracellular pH displayed asymptotic patterns of change to a new steady state. The energetic shift correlated with the slowing of heart functioning at 5C, but not at 21C when bradycardia was elicited by autonomic control.