Increased resistance of the cardiac sarcoplasmic reticulum Ca(2+)-pump to autolysis after adaptation of rats to stress.
Experiments on rats are reported in which Ca2+ uptake by the sarcoplasmic reticulum (SR) and the time course of SR Ca(2+)-pump inactivation and Ca2+ leakage from intracellular compartments into the incubation medium were studied in tissue homogenates stored at 4 degrees C. Long-term (6 h) immobilization stress significantly reduced the ability of the SR to take up Ca2+, accelerating (two- to threefold) both Ca(2+)-pump inactivation and Ca2+ leakage induced by autolysis during storage. A course of adaptation to repeated short-term stress prevented the adverse effects of long-term stress on the SR Ca(2+)-pump. Adaptation to repeated stress itself accelerated the rate of Ca2+ uptake by the SR and sharply inhibited the SR Ca(2+)-pump inactivation and Ca2+ leakage induced by autolysis. Possible mechanisms for the adaptive stabilization of SR membranes against factors that cause autolysis are discussed.
Meerson
F Z
FZ
Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow.
Sazontova
T G
TG
Arkhipenko YuV
D000222:Adaptation, Physiological; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D012149:Restraint, Physical; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013312:Stress, Physiological / Q000150:complications / Q000503:physiopathology*
D009124:Muscle Proteins; D000252:Calcium-Transporting ATPases; D002118:Calcium