[Modification of an enzymic system of Ca2+ transport in sarcoplasmic reticulum during lipid peroxidation. In vivo damages in the development of pathological changes].
The role of lipid peroxidation (LPO) in the damages of the enzymic system of Ca2+ transport in sarcoplasmic reticulum (SR) membranes of skeletal and cardiac muscles under conditions of vitamin E deficiency, ischemia and limb reoxygenation as well as in emotional-pain stress was investigated. It was shown that these processes are associated with activation of endogenous LPO in SR membranes "in vivo" and with simultaneous inhibition of Ca2+ transport, (i. e. decrease of the Ca2+/ATP ratio) and inactivation of Ca-ATPase. The degree of damage of the Ca2+ transport system was correlated with the concentration of LPO products accumulated in SR membranes "in vivo and during LPO induction by the Fe2+ + ascorbate system 'in vitro". Injection of natural and synthetic free radical scavengers (e. g. 4-methyl-2.6-ditretbutylphenol, alpha-tocopherol) to experimental animals resulted in practically complete suppression of LPO activation "in vivo" and in partial protection of the Ca2+-transporting capacity of SR membranes. A comparison of experimental results allowed to estimate the role of LPO in SR damage under pathological conditions. Model experiments with "contraction-relaxation" cycles including isolated components of muscle fibers (SR fragments and myofibrils) demonstrated that LPO induction in SR membranes by the Fe2+ + ascorbate system results in complete elimination of the relaxation step in myofibrils due to the loss of the SR affinity to decrease the concentration of Ca2+ in the incubation medium. This effect can be removed by free radical scavengers. The role of LPO in pathological changes of muscle contractility is discussed.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D003327:Coronary Disease / Q000378:metabolism; D006801:Humans; D007511:Ischemia / Q000378:metabolism; D007700:Kinetics; D008054:Lipid Peroxides / Q000378:metabolism*; D009119:Muscle Contraction; D009132:Muscles / Q000098:blood supply / Q000378:metabolism*; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D013315:Stress, Psychological / Q000378:metabolism; D014811:Vitamin E Deficiency / Q000378:metabolism*
D008054:Lipid Peroxides; D000252:Calcium-Transporting ATPases; D002118:Calcium
Modifikatsiia fermentnoĭ sistemy transporta Ca2+ v sarkoplazmaticheskom retikulume pri perekisnom okislenii lipidov. Povrezhdeniia in vivo pri razvitii patologicheskikh sostoianiĭ.