Genetic differences in tolerance to ethanol: a study in UChA and UChB rats.

The development of tolerance to ethanol was studied in two strains of rats, UChA (low ethanol consumer) and UChB (high ethanol consumer), by the sleeping time test. Marked tolerance (perhaps both metabolic and tissue) appeared in UChA rats, while only a slight tissue tolerance and not a metabolic one appeared in the UChB rats, when they were offered 10% ethanol as the sole fluid during 31 days (p less than 0.001). In UChA, but not in the UChB rats, the chronic treatment with ethanol induced tolerance to pentobarbital as shown by the same test.