Blood pressure variability is increased in genetic hypertension and L-NAME-induced hypertension

AIM: To examine whether the blood pressure variability (BPV) is increased i n spontaneously hypertensive rats (SHR) and L-NAME-induced hypertensive rat s (NHR). METHODS: BPV was recorded with continuous hemodynamic monitoring i n conscious unrestrained rats. Time course of L-NAME-induced hypertension w as measured by the tail-cuff method. Plasma NO concentration was determined by the method of nitric acid reductase. RESULTS: In both SHR and NHR, syst olic and diastolic BPV were significantly increased when compared with thei r respective controls. In SHR, increase in diastolic BPV was predominant, w hereas in NHR, increase in systolic BPV was predominant. Moreover, increase in systolic BPV in NHR (102%) was obviously higher than that in SHR (28%). Chronic administration of L-NAME 1 g/L in drinking water caused a progress ive increase in arterial blood pressure in rats. All rats were hypertensive at 4 weeks after treatment. Plasma NO level was decreased in NHR. CONCLUSI ON: Increased BPV is a general phenomenon in hypertension. NO is involved i n the regulation of BPV.