title: The effect of ischemia and reperfusion on sarcolemmal function in perfused canine hearts.
abstract: The report deals with the effect of ischemia and reperfusion on purified sarcolemma obtained from canine myocardium of perfused supported heart preparations. Perfusion was carried out with a perfluorochemical (FC-43). Ischemia was produced by intermittent total clamping of inflow and outflow followed by release until the decrease in dP/dtmax had become stabile. Purity of sarcolemmal vesicles was ascertained with marker enzymes: succinate cytochrome c reductase (for mitochondria), K+-stimulated p-nitrophenylphosphate (K+-pNPPase), (Na+/K+)ATPase and adenylate cyclase (for SL). In addition Na+/Ca2+-exchange characteristics for SL were determined. Sidedness of vesicles was ascertained by means of adenylate cyclase activity using sarcolemmal preparations treated and untreated with alamethicin. Emphasis was placed on ATP-dependent Ca2+ uptake, phosphorylation of sarcolemmal vesicles and yield of SL proteins. Ischemia and reperfusion resulted in a significant reduction in adenylate cyclase activity. This decline was significant following ischemia and reperfusion. The yield of protein recovered from SL vesicles from ischemic-reperfused heart preparations was also significantly decreased. Both initial rate of ATP-dependent Ca2+ uptake and maximal Ca2+ uptake fell significantly following ischemia and reperfusion. The initial rate of phosphorylation also dropped significantly. These disturbances in SL Ca2+ transport following ischemia and reperfusion are probably a part of the general deficit in Ca2+ translocation.
mesh_terms: D009597:4-Nitrophenylphosphatase / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000502:physiology; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism; D003327:Coronary Disease / Q000378:metabolism*; D004285:Dogs; D009124:Muscle Proteins / Q000096:biosynthesis; D009206:Myocardium / Q000378:metabolism*; D010477:Perfusion; D010766:Phosphorylation; D012508:Sarcolemma / Q000201:enzymology / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013384:Succinate Cytochrome c Oxidoreductase / Q000378:metabolism
chemical_list: D009124:Muscle Proteins; D000255:Adenosine Triphosphate; D013384:Succinate Cytochrome c Oxidoreductase; D009597:4-Nitrophenylphosphatase; D000262:Adenylyl Cyclases; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium