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

Abstract

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.