title: Studies of the cardiac sarcoplasmic reticulum in myocardial infarction.
abstract: 1. Influence of ischemia on the biochemical properties of the sarcoplasmic reticulum (SR) was studied in the experimental myocardial infarction in the dog. 2. Ca2+ -uptake rate of SR decreased at around 90 minutes after coronary occlusion. This reduction was roughly in parallel with the reduction in the Ca+ -Mg2+ -stimulated ATPase activity. However, Ca2+ -binding rate of SR was kept within the range of that of the non-infarcted tissue through the time course of myocardial infarction. 3. Ca2+ -Mg2+ -stimulated ATPase activity decreased at around 3 hours after coronary occlusion to about 50% of that of the non-infarcted portion. 4. In SDS gel electrophoresis, the protein band with the largest molecular weight among three major components decreased at 3 hours after coronary occlusion, which is suggestive of ATPase. At 48 hours after coronary occlusion, the protein with the smallest molecular weight in the major proteins also decreased. 5. Ca2+ -uptake rate, Ca2+ -Mg2+ -stimulated ATPase activity and the substructural changes return to the normal level and pattern at around 28 days after coronary occlusion.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D004285:Dogs; D066298:In Vitro Techniques; D008274:Magnesium / Q000378:metabolism; D009203:Myocardial Infarction / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
chemical_list: D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium