Polygraphic sleep studies in rats and humans: their use in psychopharmacological research

The effects of selected centrally acting drugs on sleep after single administration to rats and humans were studied using polygraphic sleep recording techniques. D-Amphetamine, a stimulant, had similar effects in both species: reduction of total sleep time, of N(non-)REM- and particularly REM (rapid eye movement)-sleep, increased restlessness during sleep. The psychodepressants mesoridazine and, in particular, nitrazepam had relatively little effects on sleep stages. In doses which did not cause side effects they reduced restlessness during sleep. The most typical effect of the antidepressant imipramine was a dose dependent reduction of REM-sleep duration in both species, without impairment of NREM-sleep. The central dopamine agonist, bromocriptin, had little effect on sleep and did not reduce total sleep and REM-sleep. These examples suggest that polygraphic sleep studies are a sensitive and stable method for the study of centrally acting drugs. The specificity of the model is illustrated by its ability to differentiate chemically and pharmacologically different drug classes. The validity of the model, i.e., its ability to allow predictions from the laboratory conditions to the therapeutic situation, varies in different drug classes. Investigations in normal subjects and animals appear to be relevant for the study of CNS-stimulants, whereas for CNS-depressants studies in sleep-disturbed subjects or animals are more likely to provide dependable results.