Apart from innate tolerance, various inbred, selectively bred, and recombinant inbred rodent strains, as well as genetically modified mouse models, have been used to assess acquired ethanol tolerance. Acute functional tolerance (AFT) is a commonly used assay to assess acute tolerance. AFT is defined as greater sensitivity to ethanol effects during the rising phase of the blood ethanol curve than equivalent ethanol concentrations on the falling phase. However, because accurately assessing blood ethanol concentrations on the rising phase is difficult due to the immediate effects of ethanol, AFT is commonly assessed by measuring the ability of a subject to exhibit a specific ethanol-related behavior (e.g., motor coordination, loss of righting reflex) during successive ethanol exposures. Blood ethanol measurements are taken upon the appearance of each behavior and the difference in blood ethanol level on the successive measurements is indicative of acute tolerance.
