Dopaminergic transmission and the sleep-wakefulness continuum in man

Modulation of dopaminergic transmission on daytime alertness and performance and on nocturnal sleep were studied in man using 30, 60 and 90 mg pemoline, a dopamimetic drug, and 2, 4 and 6 mg pimozide, a dopamine receptor antagonist. Pemoline lengthened daytime sleep latencies and improved attention, and increased wakefulness during nocturnal sleep. Rapid eye movement (REM) sleep was reduced with 90 mg pemoline, but this was due entirely to increased wakefulness. Pimozide had little effect on overnight sleep, but increased the tendency to fall asleep and impaired performance during the day. These studies suggest that the effects of certain drugs which modulate the activity of neurotransmitters, involved in the control of sleep and wakefulness, may be related to the inherent level of activity of the central nervous system. Modulation of the dopaminergic system can have a profound influence on the manifestation of wakefulness and vigilance, but is unlikely to modify directly the elaboration of REM sleep in man.