Abstract

Objective: Studies in mice and rats bred for their behavioral response to ethanol have revealed that I:here may be a relationship between acute tolerance development, sensitivity to ethanol and alcohol preference. We saw a need to obtain more genetically meaningful correlations between ethanol consumption and acute tolerance to motor impairment or sensitivity to hypothermia induced by ethanol. In the present article, we provide results on acute tolerance, sensitivity to hypothermia and voluntary ethanol consumption in an F2 generation of a cross between inbred UChA (low) and UChB (high) ethanol-consuming rats. Method: Naive UChA and UChB rats were tested for acute tolerance development to motor impairment and sensitivity to hypothermia induced by the intraperitoneal administration of a dose of ethanol of 2.3 g/kg body weight. Rats were then offered ad libitum a 10% v/v ethanol solution, distilled water and rat food, and classified according to their drinking scores. Next, one female UChA (low consumer) was mated with one male UChB (high consumer) and one female UChB (high consumer) mated with one male UChA (low consumer). The F2. generation of these inbred rats was used to test acute tolerance, sensitivity and voluntary ethanol consumption. Results: UChB rats developed acute tolerance more rapidly and were less sensitive to the ethanol dose than UChA rats. The F2 generation was designated Hybrid A (HA) for those offspring from the UChA female grandparent and Hybrid B (I-IB) for the offspring from the UChB female. Results show clearly that there is a relationship between the ability of the rat to acquire acute tolerance to motor impairment, the sensitivity to hypothermia induced by ethanol, and the ethanol preference of the rat. The multiple correlation analysis between the three behaviors showed a significant Value in HA rats (r = -0.76, p < .01) and in HB rats (r = -0.83, p < .01). Conclusions: This study of a cross between UChA and UChB rats shelved that the three parameters are related since they clustered together in the F2 generation. This result leads us to speculate that if we could control acute tolerance development in the rats we might also control their voluntary ethanol consumption.