Cerebrovascular response to arousal from NREM and REM sleep.
OBJECTIVE
To determine the effect of arousal from sleep on cerebral blood flow velocity (CBFV) in relation to associated ventilatory and systemic hemodynamic changes.


METHODS
Eleven healthy individuals (6 men, 5 women).


METHODS
Pulsed Doppler ultrasonography was used to measure CBFV in the middle cerebral artery with simultaneous measurements of sleep state (EEG, EOG, and EMG), ventilation (inductance plethysmography), heart rate (ECG), and arterial pressure (finger plethysmography). Arousals were induced by auditory tones (range: 40-80 dB; duration: 0.5 sec). Cardiovascular responses were examined beat-by-beat for 30 sec before and 30 sec after auditory tones.


RESULTS
During NREM sleep, CBFV declined following arousals (-15% +/- 2%; group mean +/- SEM) with a nadir at 9 sec after the auditory tone, followed by a gradual return to baseline. Mean arterial pressure (MAP; +20% +/- 1%) and heart rate (HR; +17% +/- 2%) increased with peaks at 5 and 3 sec after the auditory tone, respectively. Minute ventilation (VE) was increased (+35% +/- 10%) for 2 breaths after the auditory tone. In contrast, during REM sleep, CBFV increased following arousals (+15% +/- 3%) with a peak at 3 sec. MAP (+17% +/- 2%) and HR (+15% +/- 2%) increased during arousals from REM sleep with peaks at 5 and 3 sec post tone. VE increased (+16% +/- 7%) in a smaller, more sustained manner during arousals from REM sleep.


CONCLUSIONS
Arousals from NREM sleep transiently reduce CBFV, whereas arousals from REM sleep transiently increase CBFV, despite qualitatively and quantitatively similar increases in MAP, HR, and VE in the two sleep states.
Bangash
Muhammad Fuad
MF
Department of Medicine, University of Wisconsin-Madison, 53706-1532, USA.
Xie
Ailiang
A
Skatrud
James B
JB
Reichmuth
Kevin J
KJ
Barczi
Steven R
SR
Morgan
Barbara J
BJ
D000161:Acoustic Stimulation; D000328:Adult; D001143:Arousal / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging; D017286:Polysomnography; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology*; D013990:Tidal Volume / Q000502:physiology; D017585:Ultrasonography, Doppler, Transcranial
D002245:Carbon Dioxide