Sedative and hypnotic effects of Vaccinium bracteatum Thunb. through the regulation of serotonegic and GABAA-ergic systems: Involvement of 5-HT1A receptor agonistic activity

The present study was conducted to investigate the sedative and hypnotic activities of Vaccinium bracteatum Thunb. fruit (VBFW) in an animal model and to identify the underlying mechanisms of its action. VBFW exhibited sedative effects through a reduction in the locomotor activity in the open field test (OFT). In addition, VBFW significantly reduced the sleep latency and increased total sleep duration in pentobarbital-induced sleeping behaviors in mice. The effects of 4-Chloro-DL-phenylalanine methyl ester hydrochloride (PCPA) were studied in normal and serotonin-depleted mice. Additionally, the changes in the related serum corticosterone (CORT) and neurotransmitter levels were evaluated. Pretreatment with VBFW (50, and 100 mg/kg) produced a significant decrease in the immobility time in the forced swim test (FST), while VBFW 100 plus PCPA treatment attenuated the change in immobility time observed following administration of VBFW alone. However, VBFW plus PCPA treatments did not significantly influence the changes in the locomotor activity that were induced by VBFW alone. The results suggest that VBFW leads to a decrease in the levels of serum CORT and norepinephrine in the hippocampus (HC) region (P