Biperiden, 4 mg, an anticholinergic drug that is relatively selective
for the M1 receptor subtype, and bornaprine, mg, a nonselective M1 and
M2 antagonist, were administered orally in a randomized, double-blind
design to twelve healthy volunteers to investigate the effect on poly
somnographically recorded sleep. Both drugs suppressed rapid eye movem
ent (REM) sleep as reflected by an increase of REM latency and a decre
ase in the percentage of REM sleep period time with the effects of bip
eriden being more pronounced. No significant effect on slow wave sleep
was observed. The results of this study support the hypothesis that b
oth the M1 and the M2 receptor subtype are involved in the regulation
of REM sleep in humans.