Anxiogenic effect of sleep deprivation in the elevated plus-maze test in mice

Rationale: Several clinical studies demonstrate that the absence of periods of sleep is closely related to occurrence of anxiety symptoms. However, the basis of these interactions is poorly understood. Studies performed with animal models of sleep deprivation and anxiety would be helpful in the understanding of the mechanisms underlying this relationship, but some animal studies have not corroborated clinical data, reporting anxiolytic effects of sleep deprivation. Objectives: The aim of the present study was to verify the effects of different protocols of sleep deprivation in mice tested in the elevated plus-maze and to assess the effect of chlordiazepoxide and clonidine. Methods: Three-month-old male mice were sleep-deprived for 24 or 72 h using the methods of single or multiple platforms in water tanks. Mice kept in their home cages were used as controls. Plus-maze behavior was observed immediately after the deprivation period. Results: Mice that were sleep-deprived for 72 h spent a lower percent time in the open arms of the apparatus than control animals. This sleep deprivation-induced anxiety-like behavior was unaffected by treatment with chlordiazepoxide (5.0 and 7.5 mg/kg IP), but reversed by an administration of 5 or 10 mug/kg IP clonidine. Conclusion: The results indicate that under specific methodological conditions sleep deprivation causes an increase in anxiety-like behavior in mice exposed to the elevated plus-maze.