Sarcoplasmatic reticulum function in the ischemic myocardium.
The effects of different periods of myocardial ischemia on sarcoplasmatic reticulum function were studied in porcine hearts in which successive occlusions of branches of the left anterior descending coronary artery yielded myocardium ischemic for 0.5, 1 or 2 h. Sarcoplasmatic reticulum vesicles were isolated from transmural biopsies of control and ischemic segments. Ca2+ pumping ATPase was already impaired after 0.5 h of ischemia (77 +/- 9% of control, n = 5) and had decreased to 44 +/- 9% of control (n = 4) after 1 h of ischemia. The functional damage caused by ischemia may be related to an altered second messenger control of the Ca2+ pump because the in vitro phosphorylation of phospholamban by catalytic subunit was also reduced.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D003327:Coronary Disease / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010766:Phosphorylation; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D013552:Swine; D013997:Time Factors; D000099211:Phospholamban
D002118:Calcium; D002135:Calcium-Binding Proteins; D000252:Calcium-Transporting ATPases; D007473:Ion Channels; D000099211:Phospholamban