Alcohol has a dose-related effect on parasympathetic nerve activity during sleep.

BACKGROUND: The aim of this study was to identify the acute effects of ethanol on the relationship between sleep and heart rate variability (HRV) during sleep. METHODS: Ten healthy male university students were enrolled in this study. An alcoholic beverage was given to each subject at a dosage of 0 (control), 0.5 (low dose: LD), or 1.0 g (high dose: HD) of pure ethanol/kg of body weight. All experiments were performed at 3-week intervals. On the day of the experiment, a Holter electrocardiogram was attached to the subject for a 24-hour period, and the subject was instructed to drink the above-described dosage of alcoholic beverage 100 minutes before going to bed; polysomnography was then performed for 8 hours. Power spectral analysis of the HRV was performed using the maximum entropy method, and the low- (LF: 0.04 to 0.15 Hz) and high-frequency (HF: 0.15 to 0.4 Hz) components along with LF/HF ratio were calculated. RESULTS: As alcohol consumption increased, the heart rate increased and the spectral power of HRV measured at each frequency range decreased. Higher doses of ethanol also increased the LF/HF ratio compared with the measured ratio of the control group. CONCLUSIONS: Acute ethanol intake inhibits parasympathetic nerve activity and results in predominance of sympathetic nerve activity during sleep, in a dosage-dependent manner. The results of this study suggest that ethanol interferes with the restorative functions of sleep.

Diazepam reduces both arterial blood pressure and muscle sympathetic nerve activity in human.

It is known that benzodiazepines have a hypotensive effect, but the mechanism has not been well elucidated yet. To clarify whether this effect is due to central or peripheral mechanism, we administered 5 mg of diazepam or saline intravenously to healthy volunteers and assessed the change in blood pressure, heart rate, muscle sympathetic nerve activity and heart rate variability. After diazepam administration, systolic and mean blood pressure decreased significantly. Muscle sympathetic nerve activity was also significantly reduced but heart rate did not change, whereas the variables of spectral analysis of heart rate variability did not show significant change. We concluded that the hypotensive effect of diazepam in human is mainly due to the central mechanism.

Effects of Yoku-kan-san-ka-chimpi-hange on the sleep of normal healthy adult subjects.

Yoku-kan-san-ka-chimpi-hange (YKCH) is a drug used for insomnia in Japanese traditional herbal medicine. The present study evaluated the effects of YKCH on sleep by all-night polysomnography using the double-blind method. Yoku-kan-san-ka-chimpi-hange increased the total sleep time significantly, and tended to cause an increase in sleep efficiency and of stage 2 sleep, as well as a decrease of sleep latency and of stage 3 + 4 sleep. There was no apparent influence on rapid eye movement (REM) sleep. In terms of non-REM sleep, the effects of YKCH exhibit a profile similar to those of benzodiazepines.

Effects of donepezil (Aricept) on the rapid eye movement sleep of normal subjects.

Donepezil (Aricept) is a therapeutic drug for the treatment of Alzheimer's disease (AD). However, there have been only two reports describing the effects of donepezil on sleep as assessed by nocturnal polysomnography (PSG). With this in mind, the effects of donepezil on the sleep of healthy subjects was evaluated using PSG. The results indicated that the percentage of rapid eye movement sleep to total sleep time was increased significantly by a single dose of 5 mg of donepezil when given to healthy subjects immediately before retiring to bed.