Abstract
Both phases of the calcium paradox were associated with major alterations in myocardial energy metabolism. During calcium-free perfusion contractility of the heart ceased, resulting in a dramatic decrease in anaerobic and aerobic metabolism but no change in tissue high energy phosphate levels. Tissue content of most citric acid cycle intermediates were elevated, while there was a net decrease in the content of transaminase-linked amino acids. Reperfusion of the calcium-depleted heart with calcium-containing buffer failed to restore either the contractile or the metabolic state of the heart. Within seconds following calcium repletion, tissue high energy phosphate content plummeted. This occurred even though glucose utilization increased significantly and aerobic metabolism remained at levels observed in the calcium-depleted heart. Analogous to changes seen in acidosis and ischemia, alpha-ketoglutarate and citrate levels decreased abruptly. After a short delay, the levels of several key amino acids also dropped. The results support the hypothesis that the impairment of mitochondrial function contributes to the depletion of high energy phosphate stores during the calcium paradox.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
