Intra-Hippocampal Injection of Abscisic Acid Attenuates Learning and Memory Deficits, and Changes Oxidative Stress Indices in REM Sleep Deprived Rats

This study evaluated whether intra-hippocampal administration of ABA can modulate learning and memory performance and oxidative stress biomarker activities in the cerebral cortex of rats exposed to rapid eye movement (REM) sleep deprivation. Adult male Wistar rats were cannulated in the CA1 area of the hippocampus. After recovery, the rats were subjected to REM sleep deprivation for 4 days. Then, the groups of REM sleep-deprived (SD) rats were treated with ABA (5, 10, and 15 µg) and ABA (10 µg) + bicuculline (Bic), a competitive GABAA receptor antagonist. Memory and learning were evaluated with the Morris water maze (MWM) and shuttle box tests. Moreover, alterations in catalase levels as an antioxidant enzyme, MDA, and H2O2 as oxidant biomarkers were determined in rat brain cortex. REM SD rats indicated noteworthy learning and memory deficits in both the MWM and shuttle box tests when compared to control rats. However, intra-CA1 injection of ABA (10 µg) decreased cognitive impairment in REM SD rats. Bic (1 μg/rat) could not change ABA (10 µg) effects. In addition, an increase in catalase activity and a decrease in MDA and H2O2 were indicated in the brain cortex of ABA (10 µg) and ABA+ Bic treated groups. Overall, the data showed ABA's aptitude to attenuate REM sleep deprivation-induced learning and memory disruption and oxidative damage in rats. Manipulation of the GABAA receptor failed to inhibit ABA effects in REM SD rats.