Schisantherin A Exerts Sedative and Hypnotic Effects Through Regulating GABA and its Receptor in Mice and Rats

Schisandra has been used to treat insomnia for hundreds of years in China. This study was aimed at proving the contribution of Schisantherin A (STA), the most abundant component in Schisandra, on sleeping, and uncover its mechanisms. Mouse autonomic activity and sleep tests were conducted for the behavioral examinations. The γ-aminobutyric acid (GABA), glutamic acid (Glu), and glutamic acid decarboxylase (GAD) in the blood and/or brain tissues of mice and rats were measured by enzyme-linked immunosorbent assay kits, and GABAA Rα1 and GABAA Rγ2 expressions in the brain tissues of rats were detected by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot. STA decreased the autonomic activities and sleep latency, increased the number of sleeping periods, sleep time, and duration in mice, showing a sedative and hypnotic effect. STA significantly elevated GABA, reduced Glu in the blood and brain, and increased GAD in the brain. STA upregulated the expressions of GABAA Rα1 and GABAA Rγ2 mRNA in the brain of rats. Thus, STA is an active component for sedative and hypnotic effects in Schisandra and these effects may be through its regulation of the GABA/Glu ratio, GAD, and GABAA expression in mice and rats