An inborn alcohol tolerance in alcohol-preferring rats. The lack of relationship between tolerance to ethanol and the brain microsomal (Na+K+) ATPase activity.

Alcohol tolerance, measured as performance on the tilting plane after ethanol injection (2.5 g/kg body weight i.p.), was examined in the AA strain of rats which voluntarily drink large amounts of alcohol, in the ANA strain which drink very little alcohol, and in ordinary albino rats which consume intermediary amounts of alcohol. The AAs showed the highest innate ethanol tolerance; the ANAs had the lowest innate tolerance. After chronic alcohol administration, both AA and ANA strains increased their tolerance, but the AAs remained superior to the ANAs. The chronic ethanol treatment did not significantly change the (Na+K+) ATPase activity of the crude microsomal fraction of the brains of the strains.