Surges of arterial pressure during REM sleep in spontaneously hypertensive rats.
OBJECTIVE
Rapid-eye-movement sleep (REM sleep) physiologically entails arterial pressure surges. Pressure surges may lead to acute cardiovascular events in risk conditions such as arterial hypertension. We investigated whether arterial hypertension alters the rate of occurrence and the characteristics of the pressure surges during REM sleep.


METHODS
Spontaneously hypertensive rats (SHR) were compared with Wistar-Kyoto normotensive controls (WKY) and a group of SHR, in which hypertension was prevented by long-term enalapril treatment (ena-SHR).


METHODS
N/A.


METHODS
Seven male rats per group.


METHODS
Instrumentation with electrodes for polygraphic recordings, a nasal thermistor for measuring ventilatory period, and an arterial catheter for measuring arterial pressure and heart period.


RESULTS
SHR showed a significant increase in the rate of occurrence but a similar magnitude of the pressure surges during REM sleep, with respect to WKY and ena-SHR. The pressure surges were associated with a decrease of heart period and an increase of electroencephalographic theta frequency, which were significantly less pronounced in SHR than in either WKY or ena-SHR. The ventilatory period showed only a modest increase before the surges without significant differences among the groups.


CONCLUSIONS
Pressure surges independent of sleep apnea occur during REM sleep at a rate increased in SHR with respect to their controls, supporting a potential role of REM sleep in triggering acute cardiovascular events in arterial hypertension. The characteristics of the pressure surges suggest that, in SHR, the underlying central autonomic commands are increased in frequency, but not in magnitude, by arterial hypertension.
Berteotti
Chiara
C
Dipartimento di Fisiologia Umana e Generale, Università di Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy.
Franzini
Carlo
C
Lenzi
Pierluigi
P
Zoccoli
Giovanna
G
Silvani
Alessandro
A
D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D004195:Disease Models, Animal; D004567:Electrodes, Implanted; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D017286:Polysomnography; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012895:Sleep, REM / Q000502:physiology*