부산대학교 도서관

We previously described a strong concordance between nocturnal oscillations in plasma renin activity (PRA) and the rapid eye movement (REM) and non-REM (NREM) sleep cycles, but the mechanisms inducing PRA oscillations remain to be identified. This study was designed to examine whether they are linked to sleep stage-related changes in arterial blood pressure (ABP). Analysis of sleep electroencephalographic (EEG) activity in the delta frequency band, intra-arterial pressure, and PRA measured every 10 min was performed in eight healthy subjects. Simultaneously, the ratio of low frequency power to low frequency power + high frequency power [LF/(LF + HF)] was calculated using spectral analysis of R–R intervals. The cascade of physiological events that led to increased renin release during NREM sleep could be characterized. First, the LF/(LF + HF) ratio significantly (P < 10-4 ) decreased, indicating a reduction in sympathetic tone, concomitantly to a significant (P < 10-3 ) decrease in mean arterial pressure (MAP). Delta wave activity increased (P < 10-4 ) 10–20 min later and was associated with a lag of 0–10 min with a significant rise in PRA (P < 10-4 ). Rapid eye movement sleep was characterized by a significant increase (P < 10-4 ) in the LF/(LF + HF) ratio and a decrease (P < 10-4 ) in delta wave activity and PRA, whereas MAP levels were highly variable. Overnight cross-correlation analysis revealed that MAP was inversely correlated with delta wave activity and with PRA (P < 0.01 in all subjects but one). These results suggest that pressure-dependent mechanisms elicit the nocturnal PRA oscillations rather than common central processes controlling both the generation of slow waves and the release of renin from the kidney. [ABSTRACT FROM AUTHOR]