The behaviour of rats selected for their voluntary ethanol consumption

New strains of rats, preferent (HAP) and non-preferent (NAP) for ethanol were selectively outbred from a Wistar stock. The strains have now been raised to the F13 generation. The F9/10 animals, selected for this behavioural investigation, exhibited a significant phenotypic drinking behaviour and/or ethanol consumption. During a free choice between tap water and 10% ethanol solution (v/v), the mean daily alcohol intake for male and female HAP rats was 8.42 +/- 0.69 g/kg/24 h (n = 20 o) and 11.50 +/- 0.42 g/kg/24 h (n = 20 o), for male and female NAP rats 0.74 +/- 0.09 g/kg/24 h (n = 20 o) and 1.76 +/- 0.20 g/kg/24 h (n = 20 o), respectively. The NAP rats exhibited a strong aversion to the 10% ethanol solution when it was the only source fluid. In the open-field test (OFT), as compared to the NAP rats, male individuals of the HAP strain showed a lower motility in the first minute, in penetration into the inner squares, showed a longer latency to start exploration (latency to leave the center), exhibited larger rearing and grooming activity and shorter latencies to start these activities. The defecation rate was smaller and latency to defecation prolonged. Female HAP rats showed higher activity scores in penetration of outer and inner squares and a shorter latency to start exploration. They also had higher rearing but smaller grooming activity. The females exhibited identical defecation but different urination behaviour in comparison to the males. The time-to-emerge latencies of HAP rats were longer than in NAP individuals.