The effects of ethanol and diazepam were examined in long-sleep (LS) and short-sleep (SS) mice using the elevated plus-maze. Ethanol had more pronounced effects in SS mice than in LS mice. In contrast, LS mice were more sensitive to the effects of diazepam on the elevated plus-maze. The ataxic effects of ethanol were measured by rotarod performance. SS mice were more resistant to the ataxic effects of a 2.0 g/kg dose of ethanol than LS mice. Ro 15-4513 reversed ethanol's ataxic effects when administered after ethanol in both LS mice and SS mice. Pentobarbital-induced ataxia was unaffected by treatment with Ro 15-4513. Studies of competition of Ro 15-4513 on 3H-flunitrazepam binding indicated that LS and SS mice did not differ in this measure in cortex, cerebellum or hippocampus.