Response of isolated adult canine cardiac myocytes to prolonged hypoxia and reoxygenation.
Isolated adult canine ventricular myocytes incubated in the absence of glucose with the respiratory inhibitor rotenone retained 67% of ATP (control, 26.0 +/- 0.9 nmol/mg protein) during 3-h incubation, yet phosphocreatine fell to 23% of initial content. Lactate production proceeded at a constant rate of 5 nmol.mg-1.min-1 in rotenone-treated glucose-free myocytes. A 36% decline in rod-shaped cells and an increase in percent 22Na permeation from 37% in aerobic cells (approximately 13 mM intracellular sodium) to 68% in rotenone-treated glucose-free myocytes paralleled the loss of ATP. Total exchangeable calcium was maintained at control aerobic levels. Exposure of canine cells to 3-h hypoxia in the absence of glucose followed by 5-min reoxygenation resulted in a 73% decrease in ATP, a rise in calcium from 3.3 +/- 0.2 to 6.6 +/- 1.6 nmol/mg, and an increase in 22Na permeation to 111%. Under these conditions the number of rod-shaped myocytes declined by 77%, with corresponding increases in viable contracted and hypercontracted myocytes. The response of canine myocytes to severe hypoxia and reaeration contrasts greatly to earlier studies using adult rat cardiac myocytes [see Hohl et al. Am. J. Physiol. 242 (Heart Circ. Physiol. 11): H1022-H1030, 1982]. Species differences with respect to basal metabolism, rates of ATP production and degradation, and regulation of cation movements are most likely responsible for the observed differences.
Hohl
C M
CM
Department of Physiological Chemistry, Ohio State University, Columbus 43210.
Altschuld
R A
RA
D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000332:Aerobiosis; D000693:Anaerobiosis; D000818:Animals; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002478:Cells, Cultured; D004285:Dogs; D004734:Energy Metabolism / Q000187:drug effects; D000860:Hypoxia; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D012265:Ribonucleotides / Q000378:metabolism*; D012402:Rotenone / Q000494:pharmacology
D012265:Ribonucleotides; D010725:Phosphocreatine; D012402:Rotenone; D000249:Adenosine Monophosphate; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate