Alterations in antioxidant status, protein concentration, acetylcholinesterase, Na+, K+-ATPase, and Mg2+-ATPase activities in rat brain after forced swimming

The aim of this study was to investigate whether exercise stress (short [2h] or prolonged [5h] forced swimming in rats) could modulate brain total antioxidant status (TAS), tissue protein concentration, and the activities of acetylcholinesterase (ACU), Na+,K+-ATPase, and Mg2+-ATPase. Protein concentration, TAS and enzyme activities in homogenized rat brain were determined spectrophotometrically. Protein concentration was decreased by 15% (p < 0.01) and by 30% (p < 0.001) after 2 h and 5 h of forced swimming, respectively. TAS was decreased by 20-25% after 2 h or 5 h of exercise. AChE was inhibited by 30% (p < 0.001) and 45% (p < 0.001) after 2 h and 5 h of forced swimming, respectively. In contrast, Na+,K+-ATPase and Mg2+-ATPase were stimulated by 80% (p < 0.001) and 40% (p < 0.001), respectively, after 2 h of swimming and by 100% (p < 0.001) and 60% (p < 0.001), respectively, after 5 h of exercise. Control values in nontreated rats were unaltered (p > 0.05). In conclusion, short or prolonged forced swimming induces oxidative stress in rats, probably resulting in a reduction in brain protein concentration and AChE activity. In addition, a Na+, K+-ATPase and Mg2+-ATPase activation was observed under the above mentioned experimental conditions. This stress condition may modulate brain intracellular Mg2+ concentration, neural excitability, metabolic energy production, and neurotransmission.