Influence of physical activity on addiction parameters of rats exposed to amphetamine which were previously supplemented with hydrogenated vegetable fat.

Amphetamine (AMPH) and its derivatives are addictive drugs used to promote and enhance alertness, motivation, willingness, courage and wellbeing. However, their chronic use is related to memory loss, emotional instability, insomnia, psychosis and paranoia. In the last decades, modern society has included processed foods, rich in trans fatty acids (TFA), in their diet, what has been related to several health problems including increased AMPH preference and self-administration. In this scenario, physical activity appears to be useful to attenuate rewarding symptoms related to addictive drugs mainly by affecting brain neuroplasticity and neurotransmission. The current study has been developed to assess the influence of physical activity on addiction parameters of rats exposed to AMPH which were previously supplemented with hydrogenated vegetable fat (HVF), rich in TFA. After six weeks of HVF or soybean oil (SO, control group) supplementation, adult rats were conditioned with d,l-AMPH or vehicle for 14 days. Then, half of each experimental group was submitted to physical activity in treadmill running sessions (60min/day, 5 days/week) for 5 weeks. Animals were re-conditioned with AMPH or vehicle for 3 more days, to observe drug relapse. Locomotor activity and anxiety-like symptoms were observed 24h after the last AMPH reconditioning, and fatty acids composition was quantified in the ventral tegmental area, striatum and prefrontal cortex. All animals showed AMPH preference, but only SO sedentary showed drug relapse. No differences were observed in locomotor activity among groups, while HVF-supplemented group showed decreased exploration per se, and physical activity prevented this. Moreover, AMPH-HVF group showed increased anxiety-like symptoms, which were prevented by physical activity. These results indicate that HVF supplementation modifies AMPH addiction, whereas regular physical activity could be protective against both AMPH and TFA damages.

Hypoxia acclimation protects against oxidative damage and changes in prolactin and somatolactin expression in silver catfish (Rhamdia quelen) exposed to manganese.

The aim of this study was to assess the Mn toxicity to silver catfish considering Mn accumulation and oxidative status in different tissues, as well as pituitary hormone expression after acclimation to hypoxia. Silver catfish acclimated to hypoxia for 10 days and successively exposed to Mn (9.8 mg L(-1)) for an additional 10 days exhibited lower Mn accumulation in plasma, liver, kidneys and brain and prevented the hematocrit decrease observed in the normoxia group. Hypoxia acclimation also modified Mn-induced oxidative damage, which was observed by lower reactive species (RS) generation in gills and kidneys, decreased lipid peroxidation (LP) levels in gills, liver and kidneys and decreased protein carbonyl (PC) levels in liver, kidneys and brain. Manganese accumulation showed positive correlations with LP levels in gills and kidneys, as well as with PC levels in gills, liver and brain. In addition, hypoxia acclimation and Mn exposure increased catalase (CAT) activity in gills and kidneys and Na(+)/K(+)-ATPase activity in gills, liver and brain. Silver catfish that were acclimated under normoxia and exposed to Mn displayed increased pituitary prolactin (PRL) and decreased somatolactin (SL) expression. Interestingly, hypoxia acclimation prevented hormonal fluctuation of PRL and SL in fish exposed to Mn. These findings indicate that while the exposure of silver catfish to Mn under normoxia was related to metal accumulation and oxidative damage in tissues together with endocrine axis disruption, as represented by PRL and SL, hypoxia acclimation reduced waterborne Mn uptake, thereby minimizing oxidative damage and changes in hormonal profile. We hypothesized that moderate hypoxia is able to generate adaptive responses, which may be related to hormesis, thereby ameliorating Mn toxicity to silver catfish.

Exercise modifies amphetamine relapse: behavioral and oxidative markers in rats.

Exercise has been reported to attenuate rewarding symptoms related to addictive drugs mainly by affecting the brain neuroplasticity and neurotransmission. In this study, we investigated the influence of physical exercise on the behavioral and enzymatic status related to drug relapse in rats. Animals were primarily treated with amphetamine (AMPH; 4.0 mg/kg, i.p.) or vehicle (C; NaCl 0.9% solution) in the conditioned place preference (CPP) paradigm for 14 days. Half of each experimental group was then submitted to swimming sessions (60 min/day, 5 days/week) for 5 weeks. Animals were re-exposed to AMPH- or vehicle-CPP paradigm for another 3 days, in order to observe drug relapse and anxiety-like symptoms, which were observed 24h after AMPH reconditioning in CPP, and elevated plus maze (EPM), respectively, and brain biochemical evaluations were carried out subsequently. While AMPH was related to place preference and anxiety, indicating drug addiction and abstinence symptoms, respectively, physical activity was able to prevent relapse symptoms after AMPH reconditioning, as observed through consecutive decreased CPP and anxiety-like symptoms. In addition, AMPH exposure increased reactive species (RS) generation and protein carbonyl (PC) levels together with decreased activity of catalase- and Na(+)K(+)-ATPase in hippocampus. On the other hand, while all AMPH-induced effects were prevented by physical activity, there was a negative correlation between PC levels (r=0.65; p<0.003) and CAT activity, and a positive correlation between RS generation and PC levels (r=0.54; r=0.52, p<0.05) with AMPH-CPP after exercise. These results indicate that exercise has a clear beneficial influence on the prevention of psychostimulant drug relapse.