[Pharmacological influence on central serotonergic mechanisms in man and its consequences on sleep (author's transl)]

Central serotonergic mechanisms were investigated in three experiments: 1. Chronic administration (four weeks) of L-5-hydroxytryptophan (L-5 HTP 600 mg/day) plus decarboxylase inhibitor (Ro 4-4602) reduces slow-wave sleep (stages 3 + 4 = SWS) without influencing other sleep parameters. 2. Clozapine reduces SWS, increases paradoxical sleep (REM) and dissociates sleep mechanisms so that increased REM in NREM stage 1 occurs. Central serotonin levels seem to remain unaffected. 3. Parachlormethylamphetamine, a serotonin synthesis inhibitor, normalises irregular sleep and narcoleptic and cataleptic attacks of narcoleptic syndrome as well. 4. Central serotonergic mechanisms are described as having a boundary-setting function.