Different protocols of REM sleep deprivation led to controversial effects on OCD- and anxiety-like behaviors and locomotor activity in fear conditioning male and female rats with respect to BDNF expression level.

Specific protocols of rapid-eye movement (REM) sleep deprivation (SD) may lead to behavioral phenotypes considered as obsessive-compulsive disorder (OCD)-like behavior and hyperactivity (mania-like behavior). The present study aimed to assess the effects of REM SD on both sexes of control and fear conditioning (FC) rats. REM SD was induced for 1 or 2 or 3 weeks (6 h/d). Freezing, locomotor activity, anxiety-like behavior, grooming and burying marbles (OCD-like behaviors), and brain-derived neurotrophic factor (BDNF) in the hippocampus were evaluated. The results showed 1w REM SD decreased freezing in females, while 2w and 3w REM SD decreased freezing in both sexes. Locomotor activity in 2w REM SD males was increased, while was decreased in 3w group. In females, both 2w and 3w REM SD increased locomotion. REM SD in both sexes increased locomotion in FC rats. All REM SD protocols decreased anxiety in both sexes of FC rats. REM SD in control and FC rats led to OCD-like behaviors. All REM SD protocols decreased BDNF in both sexes, while 3w slightly increased it, suggesting a compensatory mechanism over time. 2w and 3w REM SD increased BDNF in FC rats in both sexes. Pearson correlation test also showed that changes in BDNF levels may be related to some behavioral changes only in females. In conclusion, for the first time, the present study showed sex differences in the effects of REM SD on behavioral functions in control and FC rats, and in the relationship between BDNF levels and behavioral changes.