RESPONSE INDUCED AT THE PLASMA MEMBRANE BY AGE AND CALORIC RESTRICTION
Michelle Rios, R. de Cabo, M. Lane
Nutritional and Molecular Physiology Unit, National Institute on Aging, NIH
Baltimore, MD USA, 21224
Caloric restriction (CR) is the only non-genetic method used to extend lifespan. Although the mechanisms by which CR works remains a mystery, the down regulation of oxidative stress have been shown to have a strong correlation with an increased lifespan. The plasma membrane constitutes a basic element in the regulation and control of the physiology of the cell. Because of its unique location and involvement in a wide variety of cellular functions the membrane is continuously exposed to damage and attack by intracellular and extracellular oxidants. Plasma membranes have their own set of antioxidant defense mechanisms that deteriorate throughout life. Aging has been associated with an increased production of reactive oxygen species and oxidation-induced damage to intracellular structures. Because it is also known that these changes occurring with age may affect membrane function and composition, we propose here that CR will preserve the integrity or delay the loss function and composition of the plasma membrane through the aging process. We isolated plasma membrane from CR and Ad libitum (AL) C57BL/6 mice, 3 months and 23 months old, using a dextran and polyethylenglycol two-phase system. We measured the activities of several plasma membrane redox activities and found increased activity of coenzyme Q reductases. This increased level of activity was also accompanied with changes in the antioxidant composition of the plasma membrane through age and food regimen.
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