Objective: It has been proposed that blood pressure variability (BPV) is positively related to end-organ damage (EOD) in hypertension. The present work was designed to observe the effects of long-term treatment with nitrendipine and hydralazine on BPV and EOD in spontaneously hypertensive rats (SHR), to examine the hypothesis that lowering BPV with an antihypertensive drug is an important factor in organ protection.
Design and methods: Drugs were mixed in rat chow. After 4 months of drug administration, blood pressure was recorded continuously in conscious freely moving rats for 24 h. The heart, kidneys, and brain were then isolated and examined.
Results: It was found that nitrendipine significantly decreased blood pressure and BPV, and significantly decreased EOD score in SHR. Hydralazine decreased blood pressure, but did not lower BPV. No effect on EOD was found in hydralazine-treated rats. In control rats (n = 38), EOD score was weakly related to systolic blood pressure (r = 0.331, P < 0.05) and closely related to long-term systolic BPV (r = 0.551, P < 0.01). In nitrendipine-treated rats, EOD score was closely related to long-term systolic BPV (r = 0.602, P < 0.01), but not to BP level (r = 0.174, P > 0.05).
Conclusion: BPV plays an important role in the organ-protecting effects of nitrendipine.
Department of Pharmacology, Second Military Medical University, Shanghai 200433, China.
Sponsorship: This work was supported by grants from the National Natural Science Foundation of China (39670831, 30070871).
Correspondence and requests for reprints to Professor Ding-Feng Su, Department of Pharmacology, Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433, China. Tel and fax: +86 21 65493951; e-mail: firstname.lastname@example.org
Received 6 September 2002 Revised 19 May 2003 Accepted 24 June 2003
See editorial commentary on page 1827