Tsakiris_2008_Br.J.Sports.Med_42_367

BACKGROUND: Forced exercise produces free radicals and L-carnitine (L-C) administration reduces oxidative stress. AIM: To investigate whether short (2 hours) or prolonged (3 hours) forced swimming could modulate total antioxidant status (TAS), protein concentration and activities of acetylcholinesterase (AChE), Na(+)K(+)-ATPase and Mg(2+)-ATPase in rat brain following intraperitonal administration of L-C (300 mg/kg).
METHODS: TAS, protein and enzyme activities were measured spectrophotometrically.
RESULTS: TAS, protein concentration and AChE activity were reduced, whereas Na(+)K(+)-ATPase and Mg(2+)-ATPase were significantly increased after either 2 or 3 hours of training. L-C administration resulted in a profound restoration of TAS and protein concentration whereas AChE and Na(+)K(+)-ATPase were increased before exercise, followed by AChE restoration and Na(+)K(+)-ATPase reduction after exercise. Mg(2+)-ATPase remained unchanged. An in vitro study using L-C incubation of brain homogenates previously treated with L-C resulted in complete restoration of the modulated enzymes, whereas the enzyme activities from untreated animals remained unaltered.
CONCLUSIONS: Short or prolonged swimming in rats may result in a reduction of brain TAS, protein concentration and AChE activity, and an activation of Na(+)K(+)-ATPase and Mg(2+)-ATPase. L-C administration may prevent reduction in TAS and protein concentration, and a decrease in AChE and Na(+)K(+)-ATPase activity; the latter reached pre-exercise values after L-C incubation.