The offspring of rats selected for high or low ethanol intake at adolescence exhibit differential ethanol-induced Fos immunoreactivity in the central amygdala and in nucleus accumbens core

FERNÁNDEZ, MACARENA SOLEDAD; FERREYRA, ANA; DE OLMOS, SOLEDAD; PAUTASSI, RICARDO MARCOS

PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2019 vol. 176 p. 6 - 15

0091-3057

Adolescents exhibit, when compared to adults, altered responsivity to the unconditional effects of ethanol. It isunclear if this has a role in the excessive ethanol intake of adolescents. Wistar rats from the third filial generation(F3) of a short-term breeding program which were selected for high (STDRHI) vs. low (STDRLO) ethanol intakeduring adolescence, were assessed for ethanol-induced (0.0, 1.25 or 2.5 g/kg) Fos immunoreactivity (Fos-ir) inthe central (Ce), basolateral (BLA) and medial (Me) amygdaloid nuclei; nucleus accumbens core and shell (AcbC,AcbSh), ventral tegmental area (VTA), as well as prelimbic and infralimbic (PrL, IL) prefrontal cortices.Following i.p. administration of saline, and across the structures measured, Fos-ir was significantly greater inSTDRHI than in STDRLO rats. Across both lines, baseline Fos-ir was significantly lower in BLA than in any otherstructure, whereas PrL, IL and Shell did not differ between each other and exhibited significantly greater level ofbaseline neural activation than Ce, Me, AcbC and VTA. STDRLO, but not STDRHI, rats exhibited ethanol-inducedFos-ir in Ce. STRDHI, but not STDRLO, rats exhibited an ethanol-induced Fos-ir depression in AcbC. Key ma-ternal care behaviors (i.e., grooming of the pups, latency to retrieve the pups, time spent in the nest and timeadopting a kiphotic posture) were fairly similar across lines. There were significant intergenerational variationsin the amount self-licking behaviors in STDRHI dams as well as an increased amount of exploration of the cage inthese animals, when compared to STDRLO counterparts. These results indicate that short term selection fordifferential alcohol intake during adolescence yields heightened neural activity at baseline (i.e., after vehicle) inSTRDHI vs. STDRLO adolescent rats, and differential sensitivity to ethanol-induced Fos immunoreactivity in Ceand in AcbC. It is unlikely that rearing patterns explained the neural differences reported, between STDRHI andSTDRLO rats