Short-term selection for high- and low ethanol intake during adolescence

PAUTASSI R.M; MACARENA FERNÁNDEZ; CHINER, F.; FERREYRA, A.

Puerto Varas

Congreso; VIII LASBRA International meeting: ?Neurobiological basis of alcoholism: from molecules to behavior?; 2017

Latin American Society for Biomedical Research on Alcoholism

The majority of diagnoses of alcohol abuse and dependence take place in the age range of adolescence and young adulthood. The mechanisms underlying the rapid transition from adolescent onset of alcohol intake to alcohol abuse problems are yet not understood. Some theories postulate that the adolescents may exhibit enhanced sensitivity to alcohol?s appetitive yet blunted responsivity to ethanol?s aversive effects. Yet this patter does not help explain why only a minor fraction of adolescents progress to problematic patterns of ethanol intake, despite being exposed to similar levels of alcohol. Preclinical, animal models may help dissect the mechanisms underlying this phenomenon. In the present study we produced rodent strains short-term, selectively, bred for high or low ethanol intake during adolescence. To our knowledge, selective breeding program for low and high levels of ethanol drinking have been performed in adulthood but not during adolescence. We short-term produced two lines of rat, as a function of high (STDRHI) or low (STDRLO) ethanol consumption during adolescence. These lines were derived from a founding population of approximately 120 heterogeneous Wistar rats. Besides the expected differences in the selected trait, STDRHI adolescent rats had, in comparison with STDRLO peers, greater innate anxiety in the open field and light-dark transition tests, as well as significantly greater ethanol-induced behavioral stimulation and a reduced conditioned taste aversion by ethanol. STDRHI rats also exhibit heightened baseline neural activation, as measured via Fos immunoreactivity (Fos-ir), in nucleus accumbens core (AcbC) and ventral tegmental area (VTA), and in central, basolateral and medial amygdaloid nucleus (Bla, Cem and Me, respectively). Ethanol-induced Fos-ir in Cem was exhibited by STDRLO, but not by STDRHI. It seems that those adolescent with greater likehood of exhibiting ethanol intake also exhibit an anxiety-prone phenotype, greater responsivity to ethanol?s appetitive yet reduced sensitivity to ethanol?s aversive effects, and an altered pattern of baseline and ethanol-induced neural response to the drug.