Mycelial Extract of Cultured Cordyceps sinensis Improves the Sleep Disturbance Induced by Placing Rats on the Grid Suspended over Water

This study aimed to evaluate the effect of mycelial extract of cultured Cordyceps sinensis（CS extract）on the sleep disturbance by placing rats on the grid suspended over water. Wake, non-rapid eye-moving（non-REM）sleep and rapid eye-moving（REM）sleep were analyzed by computer software, simultaneously measuring electroencephalogram and electromyogram. Significant increase of wake duration, decrease of non-REM sleep duration and delay of sleep latency were observed by sleep disturbance for 3 hrs, but not after 4 hr. On the REM sleep, no significant difference was observed. CS extract attenuated the increase of wake and significantly decreased non-REM sleep by the sleep disturbance. In addition, the delayed sleep latency was significantly improved. Zopiclone, hypnotic drug used in clinic, also showed the same effects as CS extract. These results show that CS extract may be useful for the treatment of stress-induced sleep disturbance. Moreover, rats showed the adaptability for stress-induced sleep disturbance at early time.