The EEG power spectrum analysis and sleep-wake behavior after stimulation of acetylcholine receptors in medial septum in rats

Abstract

Medial septum (MS) in consist of the complex interneuronal circuits of Cholinergic, Glutametergic and GAB Aergic receptors containing neurons. In the present study, the muscarinic acetylcholine (m Ach) receptors in MS were stimulated to assess the power spectrum of cortical EEG and sleep-wake behavior. After stimulation of m Ach receptors by putative Ach, the power of Alpha and Beta wave was increased in both wake and slow wave sleep (SWS) condition. But, the power of Delta wave was decreased in both wake and SWS condition. The decreased power of theta wave was found only in SWS condition. No effect was found in power spectrum study after stimulation of the m Ach receptors in REM sleep condition. After micro infusion of Ach into MS, the duration of wake, SWS and REM sleep were not significantly altered compared to that of pre-infusion values. The duration of sleep-wake and the power of EEG remained unaltered after micro infusion of vehicle into MS. Though the duration of sleep-wake cycle is not affected by the stimulation of m Ach receptors, but the power spectrum analysis indicates the there may have some activation / deactivation effects of m Ach receptors on cortical EEG.