Comparative study between n-6, trans and n-3 fatty acids on repeated amphetamine exposure: a possible factor for the development of mania.

In the last decades, foods rich in omega-3 (ω-3) fatty acids (FA) have been replaced by omega-6 (ω-6) and trans FA, which are found in processed foods. The influence of ω-6 (soybean oil--SO), trans (hydrogenated vegetable fat--HVF) and ω-3 (fish oil--FO) fatty acids on locomotor and oxidative stress (OS) parameters were studied in an animal model of mania. Rats orally fed with SO, HVF and FO for 8 weeks received daily injections of amphetamine (AMPH--4 mg/kg/mL-ip) for the last week of oral supplementation. HVF induced hyperactivity, increased the protein carbonyl levels in the cortex and decreased the mitochondrial viability in cortex and striatum. AMPH-treatment increased the locomotion and decreased the mitochondrial viability in all groups, but its neurotoxicity was higher in the HVF group. Similarly, AMPH administration increased the protein carbonyl levels in striatum and cortex of HVF-supplemented rats. AMPH reduced the vitamin-C plasmatic levels of SO and HVF-fed rats, whereas no change was observed in the FO group. Our findings suggest that trans fatty acids increased the oxidative damage per se and exacerbated the AMPH-induced effects. The impact of trans fatty acids consumption on neuronal diseases and its consequences in brain functions must be further evaluated.

Intense exercise potentiates oxidative stress in striatum of reserpine-treated animals.

Regular physical activity exerts beneficial effects for mental and physical health, but an intense exercise can cause oxidative stress (OS) in dopaminergic regions and intensify the harmful effects of reserpine. Reserpine-induced neurotoxicity can be accessed by behavioral and biochemical evaluations. The objective of this study was to examine the effect of a gradual intensifying exercise program on an animal model of oxidative stress. Male rats were submitted to swimming sessions (1 h/day, for eleven weeks), and they were loaded gradually during the adaptation period (two weeks) with a weight corresponding to 1-7% of their body weight tied to their back. After the last training, the animals were treated with two doses of vehicle or reserpine (1 mg/kg-sc), an agent that induces orofacial dyskinesia. After behavioral evaluations, the striatum was dissected for enzymatic and biochemical assays. Development of cardiac hypertrophy demonstrated the effectiveness of the physical training. The gradual intense exercise and reserpine increased lipid peroxidation and striatal catalase activity. The results confirm the importance of catalase activity in orofacial dyskinesia which can be related to lipid peroxidation in striatal dopaminergic brain tissue. These results indicate that intense exercise can have some deleterious effect on striatal dopaminergic system.

Influence of chronic exercise on reserpine-induced oxidative stress in rats: behavioral and antioxidant evaluations.

Several neurological diseases are related to oxidative stress (OS) and neurotoxicity. Considering that physical exercise may exert beneficial effects on antioxidant defenses, our objective was to evaluate the influence of a swimming exercise on an OS animal model (reserpine-induced orofacial dyskinesia). In this model, the increased dopamine metabolism can generate OS and neuronal degeneration, causing involuntary movements. The increase in vacuous chewing movements and facial twitching caused by reserpine (1 mg/kg s.c.) was partially prevented by exercise. An increase in catalase activity and a decrease in GSH levels were observed in the striatum. Physical training did not change the effects of reserpine on catalase, however it partially recovered GSH. Exercise per se caused a significant GSH decrease. There was a positive correlation between catalase and OD (r=0.41; r=0.47, P<0.05) and a negative correlation between GSH and OD (r=0.61; r=0.71, P<0.05). These results reveal the benefit of exercise in attenuating the motor disorder related to OS.