RAPID EYE-MOVEMENT SLEEP-DEPRIVATION AND HYPERTENSION - GENETIC INFLUENCE

We studied the importance of genetic predisposition in the development of stress-induced hypertension in the spontaneously hypertensive rat (SHR), Wistar-Kyoto (WKY) rat, and borderline hypertensive rat (BHR; first-generation offspring of SHR and WKY). Rats were submitted to seven 72-hour sessions of rapid eye movement sleep deprivation (REM-sd) every other week during 13 weeks. Tail arterial pressure was determined throughout the experiment. At the end of the study, mean arterial pressure (direct measurement), sympathetic activity (acute blockade with propranolol and phentolamine), and ventricular weight were determined. Results showed that REM-sd induced sustained hypertension only in rats with a partial predisposition to developing hypertension (BHRs). Values of tail arterial pressure at the end of the study were BHR REM-sd, 175 +/- 1.6 mm Hg and control BHR, 155.9 +/- 0.9 mm Hg, p < 0.05; SHR REM-sd, 219 +/- 2.6 mm Hg and control SHR, 211.9 +/- 3.4 mm Hg, NS; WKY REM-sd, 123.9 +/- 2 mm Hg and control WKY, 125.4 +/- 2.2 mm Hg, NS. Stressed groups showed higher reduction of mean arterial pressure than their controls when submitted to sympathetic blockade (SHR REM-sd, -75.7 +/- 13.2 mm Hg and control SHR, -60 +/- 4.5 mm Hg, p < 0.05; BHR REM-sd, -38.4 +/- 3.6 mm Hg and control BHR, -24.3 +/- 2.1 mm Hg, NS; WKY REM-sd, -34.4 +/- 2.5 mm Hg and control WKY, -25.6 +/- 3.3 mm Hg, NS). REM-sd increased ventricular weight in all strains. These increments showed no correlation with blood pressure. In conclusion, chronic and intermittent REM-sd induced sustained hypertension only in rats with a partial predisposition to developing hypertension (BHRs) and increased ventricular weight in all strains.