The effects of indalpine--a selective inhibitor of 5-HT uptake--on rat paradoxical sleep.

In order to document the role of monoamines in the reduction of paradoxical sleep by antidepressant drugs, we examined the effect of indalpine , a selective inhibitor of serotonin uptake. Indalpine dose dependently decreased paradoxical sleep and delayed its first appearance. Pretreatment with parachlorophenylalanine markedly decreased the effect of indalpine . In contrast, pretreatment with alpha-methylparatyrosine potentiated the indalpine -induced depression of paradoxical sleep. The results of the study indicate that the increase of extracellular concentration of 5-HT has an inhibitory effect on paradoxical sleep, and this effect is enlarged if catecholaminergic activity is reduced.