Efeitos da exposição combinada de cafeína e etanol durante o desenvolvimento na atividade locomotora de camundongos adolescentes

Abstract

The attention deficit hyperactivity disorder (ADHD) is a neurobehavioral disorder characterized by varying degrees of inattention, excessive motor activity and impulsivity. This etiology is not fully known, but considerable evidence suggests that, in addition to genetic factors, exposure to ethanol and high doses of caffeine contribute to the manifestation of the disorder. Ethanol, which is present in all alcoholic beverages, and caffeine, which is present in many beverages (sodas, teas, coffee and energetic drinks), food derived from cacao and medications, are two of the most consumed neuroactive drugs in the world. In spite of the epidemiological evidence of the combined use of caffeine and ethanol by pregnant women, the interactions between these two drugs have received little attention in experimental studies. This fact is particularly important since some studies have shown that caffeine is capable of amplifying important aspects of the action of other substances that have neurotoxic potential. In the current study we analyzed the effects of co-exposure to caffeine and ethanol during development on the locomotor activity of pre-pubertal mice. In this sense, Swiss mice were exposed from the first gestational day to the 21st postnatal (PN21) day to one of three solutions: 1) a solution containing caffeine 0.1 g/L (group CAF1, 10 litters); 2) a solution containing caffeine 0.3g/L (group CAF3, 10 litters); 3) filtered tap water (group CAF0, 10 litters). Every other day, from PN2 to PN8, animals in each litter were i.p injected with one of the following solutions: 1) 0.25 µl/g ethanol (group ETOH25); 2) 0.5 µl/g ethanol (group ETOH50); 3) saline solution (group ETOH0). On PN30, locomotor activity was analyzed for 15 min in the open field. The analysis of the ethanol serum levels, which was carried out in an independent sample of animals at PN8, indicated that levels were significantly higher in the CAF3 group when compared to the other two groups, which did not differ between them. In the open field, the ethanol exposure caused a dose-dependent increase in the locomotor activity. The locomotor activity of the group ETOH0 was lower than that presented by the ETOH25 and the ETOH50 groups. The caffeine exposure was not capable of affecting the locomotor activity. In the group CAF3, the locomotor activity was not affected by the ethanol exposure. Our data corroborate previous studies in that it shows that precocious ethanol exposure results in locomotor hyperactivity. Furthermore, it is possible that caffeine exposure during development have a protective effect on deleterious effects of ethanol.