Correlation Between Functional Recovery From Ischemia and Sarcoplasmic Reticulum Calcium Content Measured by Electron Probe MicroAnalysis

Abstract

<jats:p>Myocardial ischemia is defined as a cessation of blood flow to the heart, and reperfusion as a return to normal flow conditions following ischemia. It has been shown that contractility decreases immediately during ischemia and diastolic dysfunctiuon may persist during reperfusion. Changes in contractility can be directly attributed to intracellular Ca<jats:sup>2+</jats:sup> handling, either by altering the myofilament sensitivity to calcium or by affecting Ca<jats:sup>2+</jats:sup> cycling by the sarcoplasmic reticulum (SR). Previous studies have demonstrated that there are changes in intracellular Ca<jats:sup>2+</jats:sup> cycling following ischemia and during reperfusion. The goals of the present study were: 1) to assess the effects of varying periods of ischemia on the size of the releasable (diastolic) SR Ca<jats:sup>2+</jats:sup> store; 2) to determine whether changes in the size of the SR Ca<jats:sup>2+</jats:sup> store are related to ischemia or reperfusion; 3) to correlate changes in the size of the SR Ca<jats:sup>2+</jats:sup> store following ischemia with functional recovery of the heart.</jats:p>