DHEA ADMINISTRATION INCREASES RAPID EYE-MOVEMENT SLEEP AND EEG POWER IN THE SIGMA-FREQUENCY-RANGE

Dehydroepiandrosterone (DHEA) exhibits various behavioral effects in m ammals, at least one of which is enhancement of memory that appears to be mediated by an interaction with the gamma-aminobutyric acid(A), (G ABA(A)) receptor complex. We investigated the effects of a single oral dose of DHEA (500 mg) on sleep stages, sleep stage-specific electroen cephalogram (EEG) power spectra, and concurrent hormone secretion in 1 0 healthy young men. DHEA administration induced a significant (P < 0. 05) increase in rapid eye movement (REM) sleep, whereas all other slee p variables remained unchanged compared with the placebo condition. Sp ectral analysis of five selected EEG bands revealed significantly (P < 0.05) enhanced EEG activity in the sigma frequency range during REM s leep in the first 2-h sleep period after DHEA administration. In contr ast, the EEG power spectra of non-REM sleep were not affected, nor wer e the nocturnal time course curves of plasma cortisol, growth hormone, or testosterone concentration. The results suggest that DHEA administ ration has a mixed GABA(A)-agonistic/antagonistic effect, exerted eith er directly or through DHEA-induced changes in steroid metabolism. Bec ause REM sleep has been implicated in memory storage, its augmentation in the present study suggests the potential clinical usefulness of DH EA in age-related dementia.