EFFECTS OF A D-2 RECEPTOR AGONIST RO-41-9067 ALONE AND WITH CLONIDINEON SLEEP PARAMETERS IN THE RAT

The effects of RO 41-9067, a D-2 dopamine receptors agonist, on differ ent sleep parameters were studied in the rat. RO 41-9067 dose dependen tly decreased paradoxical sleep, and only at the higher dose increased waking during the light period. In contrast, the higher dose of RO 41 -9067 increased paradoxical sleep and decreased waking during the dark period. Finally, the combination of RO 41-9067 and clonidine signific antly prevent the decrease of total sleep time and paradoxical sleep f ound after clonidine alone. These results, compared with those of clas sical D-2 dopamine receptors agonists, suggest an action for RO 41-906 7 on D-2 dopamine receptors depending on the cerebral structure, a dif ferent action particularly on the striatum and/or on the structures re sponsible for paradoxical sleep. An active role for D-2 dopamine recep tors and an interaction between noradrenergic and dopaminergic systems in the regulation of sleep is proposed.