Suppression of REM and delta sleep by apomorphine in man: a dopamine mimetic effect.

Apomorphine, a direct stimulant of dopamine receptors, was given in nonemetic doses by continuous IV infusion for 180-240 min during night sleep in normal subjects. During apomorphine infusion, a significant reduction of stage (S)4 and an abolition of rapid eye movement (REM) sleep occurred. The percent duration of S2 was significantly increased. In the 240 min following interruption of 240-min infusion of apomorphine, a significant increase of S4 and REM percent duration was observed. The effect of apomorphine infusion on sleep was prevented by the administration of haloperidol or sulpiride, two dopamine receptor blocking agents. This suggests that it is due to a dopamine mimetic action.