Hypnotics: clinical value of pharmaco-EEG methods.

The central effects of sedative-hypnotic drugs were defined through the use of electroencephalographic (EEG) techniques in two species (rat and cat). In immobilized rats, spectral and visual electrocorticogram analysis provides a means of studying and comparing different profiles of sedative-hypnotic drugs. As with spectral analysis, Hjorth's descriptors allow one to detect the sedative effects of drugs and to study drug interactions in acute preparations. We have evaluated the action of hypnotics on the sleep-wakefulness cycle in freely implanted rats during their maximally active period because it is easier to estimate the duration of the sedative effect. We have also examined the action of sedative-hypnotic agents in rats and cats because of the different species reactivity to drugs such as benzodiazepines. These EEG methods are of value in the development of new hypnotic agents.