Differential effects of scopolamine and chlorpromazine on REM and NREM sleep in normal male subiects

The study compares the effects of scopolamine, methscopolamine, and chlorpromazine on the EEG and the EOG in sleeping subjects. Saline was used as a control. Scopolamine hydrobromide (0.006 mg. per kilogram) clearly retarded the onset of stage REM. No immediate rebound was seien in the analysis of the sleep pattern for two hours after the first recording of this stage. The total amount of REM sleep during the full period of recording was therefore diminished. The decrease in REM resulted in an increased amount of stages I and II. No significant changes were observed in stages III or IV or in the periods of wakefulness. A significant increase in body movements was noted. Methscopolamine bromide (0.0055 mg. per kilogram) did not produce any substantial modification in the pattern of sleep. Chlorpromazine hydrochloride (0.4 mg. per kilogram) produced an increase of stage III activity apparently at the expense of stage II sleep. The observed changes further support a role of cholinergic mechanisms in human REM sleep.