Sleep apnea in normal and REM sleep-deprived normotensive Wistar-Kyoto and spontaneously hypertensive (SHR) rats.

The effects of hypertension and REM sleep deprivation on spontaneous and postsigh apneas have been studied in normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats by simultaneously monitoring their respiration and sleep by the EEG. The amount of REM and non-REM sleep in SHR rats was identical to WKY rats under control as well as REM sleep-deprived recording conditions. Hypertension was associated with an increase in postsigh apneas, as was evident by the increased postsigh apnea index in non-REM and total sleep in SHR rats when compared to normotensive WKY rats. In contrast, REM sleep deprivation suppressed the postsigh apnea expression both in non-REM and total sleep in SHR rats. The incidence of spontaneous apneas was increased by a combination of hypertension and REM sleep deprivation, as was shown in REM-deprived SHR rats, while each of these conditions alone had no effect on spontaneous apneas. These results suggest a role for hypertension in the postsigh apnea genesis and the existence of partially distinct mechanisms for the two types of apneas.