SLOW-WAVE ELECTROENCEPHALIC ACTIVITY PARALLELS RENIN OSCILLATIONS DURING SLEEP IN HUMANS

Previous studies have demonstrated that the nocturnal oscillations of plasma renin activity (PRA) exactly reflect rapid eye movement (REM) n on-REM (NREM) sleep alternation with levels of PRA that increase durin g NREM sleep and decrease during REM sleep. These studies were based e xclusively on conventional scoring of sleep stages. In the present stu dy, we used spectral analysis of the sleep EEG to determine the variat ions in the different EEG frequency bands, together with PRA profiles. Eight male volunteers participated in a 1 night study. They were subj ected to 8 h polysomnography, including spectral analysis of the EEG, and to blood sampling every 10 min. Delta relative power and Sleep Int ensity Index and PRA oscillations ran parallel in all individuals. An increase in slow waves was associated with an increase in PRA, whereas a decrease was associated with a decrease in PRA. Cross-correlation c oefficients were significant and ranged between 0.34 and 0.74. Convers ely, theta, alpha and beta bands and the EEG mean frequency were inver sely proportional to PRA, with lower cross-correlation coefficients. T hese results may give further support to the hypothesis of a common me chanism controlling both SWA and renin release from the kidney.