Behavioural features of alcohol-preferring rats: Focus on inbred strains

A recent study conducted a factor analysis on 18 behavioural measures obtai ned from four alcohol-preferring and five alcohol-non-preferring rat lines/ strains. It was concluded that variables such as saccharin intake, ultrason ic vocalizations following an air puff, and defaecation in an open field we re associated with voluntary and forced alcohol consumption. In contrast, m easures such as time immobile in the forced swim test and time spent in the open arms of the elevated plus maze were not consistently associated with voluntary alcohol intake. The present study focuses on alcohol intake and r elated measures in four inbred strains of Fawn-Hooded (FH) rats that differ in voluntary alcohol intake and the ACI/N inbred rat strain, which volunta rily consumes very little alcohol. FH rats inbred by Jean Dodds (FH/Wjd) dr ank significantly more alcohol than FH rats inbred by Gordon Harrington (FH /Har) or selectively inbred by Abraham Provoost (FHH/Eur and FHL/EUR). In c ontrast, only the FH/Har strain was active in the forced swim test, suggest ing that immobility and voluntary alcohol intake may be influenced by diffe rent genetic factors. The FH/Wjd rats were also much more immobile than the ACI/N rats in the forced swim test and drank almost 10 times as much alcoh ol voluntarily. Comparing the two parental lines with reciprocal Fl crosses revealed that alcohol consumption was influenced largely by additive genet ic factors (FI progeny had intermediate scores), whereas immobility was als o influenced by dominance genetic factors (F1 progeny resembled the FH/Wjd parent). Preliminary analysis of 43 F2 progeny indicated that alcohol intak e and immobility were not correlated. Thus, immobility in the forced swim t est and high voluntary consumption of alcohol, two prominent features of th e FH/Wjd rat strain which may be related to its serotonergic dysfunction, a ppear to be mediated by different genetic factors.