Effects of red ginseng extract on sleep architecture and electroencephalogram power spectra in rats

Abstract

We evaluated the ability of the ethanol extract of red ginseng (RGE) to regulate sleep architecture. Adult rats were chronically fitted with sleep-wake recording electrodes. Following post-surgical recovery, rats were habituated extensively to freely moving polygraphic recording conditions. Polygraphic signs of undisturbed sleep-wake activities were recorded for 12 h after RGE administration. Ginseng treatment produced more time in non-rapid eye movement (NREM) sleep and total sleep. The total percentage of wakefulness decreased comparably, and the number of sleep-wake cycles was reduced after 10 and 50 mg/kg RGE. RGE (10 mg/kg) administration decreased the power density of cortical electroencephalogram (EEG) δ-waves (0.75–4.5 Hz) and increased α-waves (8.0–13.0 Hz) in NREM and rapid eye movement (REM) sleep. It also decreased δ-wave power density during wakefulness. Although 100 mg/kg RGE showed little effect on the power densities in NREM and REM sleep, it increased δ-wave and decreased θ-wave (5.0–9.0 Hz) power densities during wakefulness. Thus, RGE increases spontaneous sleep and NREM sleep. Regulation of sleep architecture by RGE involves decreased δ- and θ-wave and increased α-wave activities according to cortical EEG.