Acute tolerance is mediated by CRF1 receptor in mice. A, R121919-treated mice (N = 19) were less able to remain on the rotarod than vehicle-treated mice (N = 21) for 60-90 minutes after receiving 2 g/kg ethanol. B, The ethanol dose required to cause initial loss of righting reflex in 50% of mice (ED50) for ethanol-induced ataxia was similar for R121919- and vehicle-treated mice (n = 6 per group). Data are mean values ± 95% CI. C, AFT magnitude was lower in R121919-treated mice (n = 22) than in vehicle-treated mice (n = 23). *P < 0.05 by two-tailed t-test. D, The rate of development of AFT was also lower in R121919-treated mice (n = 22) than in vehicle-treated mice (n = 23). *P < 0.05 by two-tailed t-test. E, Ethanol clearance was similar for R121919- and vehicle-treated mice (n = 6 per group). Data are mean ± SEM values.