Effects of several centrally active drugs on the sleep-wakefulness cycle of cats

Abstract

Eighteen drugs were injected intraperitoneally at different doses in cats and their effects on the sleep-wakefulness cycle studied in 6-hr sessions of telemetric EEG and EMG recording. At the lowest doses that affected the sleep-wakefulness cycle, clinically used and potential antidepressants (imipramine, clomipramine, desipramine, amitriptyline, nortriptyline, maprotiline, Ro 03-5939, mianserin, iprindole, viloxazine, pargyline, Ro 11-1163) as well as 5-hydroxy-l-tryptophan selectively depressed rapid eye movement (REM) sleep. Other psychotropic drugs also reduced REM sleep but, in contrast to the above antidepressants, simultaneously affected non-rapid eye movement (NREM) sleep at minimum effective doses: LSD, methylphenidate and, to a lesser degree, haioperidol, depressed, whereas cyproheptadine augmented NREM sleep. Chlorpromazine non-significantly reduced REM sleep at a dose that induced ataxia. The results reveal a selective suppressant effect of antidepressant drugs on REM sleep in cats which seems to reflect an increased activation of 5-hydroxytryptamine and/or noradrenaline receptors in the brain as the consequence of either inhibition ofmonoamine uptake or monoamine oxidase, increased release of monoamines or some yet unknown mechanisms. © 1979.