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 a nd postsigh apneas have been studied in normotensive Wistar-Kyoto (WKY ) and spontaneously hypertensive (SHR) rats by simultaneously monitori ng their respiration and sleep by the EEG. The amount of REM and non-R EM sleep in SHR rats was identical to WKY rats under control as well a s 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 compa red to normotensive WKY rats. In contrast, REM sleep deprivation suppr essed the postsigh apnea expression both in non-REM and total sleep in SHR rats. The incidence of spontaneous apneas was increased by a comb ination 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.