Effect of Withania somnifera on Sleep-Wake Cycle in Sleep-Disturbed Rats: Possible GABAergic Mechanism

Indian J Pharm Sci. 2008 Nov;70(6):806-10. doi: 10.4103/0250-474X.49130.


Sleep deprivation disrupts significantly sleep pattern and cause poor quality of sleep. The aim the present study was to explore role of Withania somniferra root extract in sleep-disturbed rats. Male wistar rats (n=5-6/group) were sleep deprived for 24 h using grid suspended over water method. Withania somniferra extract (100 mg/kg) was administered intraperitoneally (i.p.) 30 min before actual recording (EEG and EMG) recording and electrophysiological recordings are further classified as- sleep latency, slow wave sleep, paradoxical sleep, total sleep, wakefulness. One day (24 h) sleep deprivation delayed latency sleep, reduced duration of slow wave sleep, rapid eye movement sleep, total sleep time and increased total waking as compared to animals placed on saw dust (P<0.05). Pretreatment with Withania somniferra extract (100 mg/kg) and diazepam (0.5 mg/kg) significantly improved electrophysiological parameters, which was further reversed by picrotoxin (2 mg/kg) and potentiated by muscimol (0.05 mg/kg). Flumazenil (2 mg/kg) did not produce any significant effect on the sleep parameters of Withania somnifera root extract. Present study suggests the involvement of GABAergic mechanism in the sleep promoting effect of Withania somniferra in sleep-disturbed state.

Keywords: EEG; EMG; Sleep; sleep deprivation.