Ethanol-induced c-Fos expression in rat lines selected for low and high alcohol consumption.

Selectively bred rat lines, developed to model genetic contributions to alcohol abuse, include the Indiana alcohol-preferring (P) and alcohol-nonpreferring (NP) lines, and the Alko-Alcohol (AA) and Alko-Nonalcohol (ANA) lines. Preferring and nonpreferring lines were compared in their response to intraperitoneal injection of either ethanol or isotonic saline using c-Fos expression as a marker of neuronal activity. Although line differences were noted in several brain regions, the principal finding was that alcohol-nonpreferring lines (NP and ANA) displayed greater c-Fos expression in the locus coeruleus (LC) relative to the alcohol-preferring lines (P and AA) following injection of 3.0 g ethanol/kg. These data point to the LC as an area which may play a role in the differences in voluntary ethanol consumption between rat lines genetically bred for low and high ethanol preference.