[Supppression of paradoxical sleep by chloramphenicol. Absence of effect by thiamphenicol]

The oral administration of 160-250 mg/kg of chloramphenicol selectively suppresses Paradoxical Sleep in the cat for a duration of 10-20 hours. Larger doses (330 mg/kg) suppress Paradoxical Sleep for 27 hours, but aslso decrease Slow Wave Sleep. At the same dose, Thiamphenicol has no effect.