Environmental Enrichment enhances alcohol intake in female adolescent rats

BERARDO. L.; PAUTASSI R.M.; FABIO M.C.

Mar del Plata

Congreso; XXXII Congreso Annual de la Sociedad Argentina de Neurociencias; 2017

Sociedad Argentina de Neurociencias

There is considerable interest in the use of enriched environments (EE) to prevent development of alcohol (i.e., the drug also known as ethanol) and other drug disorders. Exposure to EE, which in rodents involve larger-than-usual home cages with interactive objects, including tunnels, toys and running wheels that provide opportunity for voluntary physical activity, reduces alcohol drinking, alcohol-induced behavioral sensitization (Rueda et al., 2012) and the rewarding effects of this drug (de Carvalho et al., 2010) and cocaine (Solinas et al., 2009. There are, however, conflicting results, with a few, yet intriguing, studies (e.g., Fernandez-Teruel et al., 2002) indicating greater ethanol intake after prolonged EE exposure. In this work, we assessed ethanol intake in adolescent rats, males and females, exposed to maternal separation during infancy (postnatal days 1-21) and environmental enrichment (EE) during adolescence (postnatal days 21-41). Ethanol intake was tested in 12, two-bottle daily sessions, spread across 30 days. We found a significant, two-fold increase (i.e., approximately 6.0 vs 3.0 g/kg/24h) in ethanol intake in males ? but not in females -- that had been exposed to EE than in control counterparts, an effect that was not modified by maternal separation. In other experiments we assessed several effects of EE that could explain its promoting effect upon ethanol intake. Ethanol-induced sleep time, sedation and aversion were unaffected by EE, which also did not modify anxiety response patterns. EE, nevertheless, resulted in greater novelty seeking and risk taking behaviors, which were evaluated in a modified version of the concentric square field test. These results put a cautionary note to the use of enriched environments as a means to prevent alcohol initiation, at least during adolescence, a developmental stage characterized by high levels of sensation seeking and novelty response. It is possible that exposure to EE further exacerbates this age-typical behaviors, thus increasing the risk for alcohol initiation and escalation. Future studies should take into account this potential side-effect of EE.