Effects of the selective 5-hydroxytryptamine uptake inhibitors paroxetine and zimeldine on EEG sleep and waking stages in the rat.

The effects of oral paroxetine and zimeldine on EEG sleep-waking phases in the rat were investigated over a wide dose range. To ascertain that at the doses used for the EEG studies paroxetine and zimeldine selectively affect the serotoninergic system, their effects on brain 5-hydroxytryptamine (5-HT), dopamine and noradrenaline were determined. It was found that paroxetine and zimeldine at doses of 1-18 mg/kg dose-dependently prolonged waking and shortened slow-wave sleep and paradoxical sleep. In the same dose range cortical 5-HT turnover was significantly reduced, whereas the other aminergic systems were not influenced. These results suggest that 5-HT uptake inhibitors increase vigilance in rats at oral doses which selectively stimulate the serotoninergic system.