Pressure-independent baroreflex resetting produced by chronic infusion of angiotensin II in rabbits.
Pressure-independent baroreflex resetting produced by chronic infusion of angiotensin II in rabbits.
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DOI：
10.1152/ajpheart.1993.265.4.h1275
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发表时间：
1993-10
期刊：
影响因子：
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通讯作者：
Virginia L. Brooks;K. Ell;R. M. Wright
中科院分区：
文献类型：
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作者：
Virginia L. Brooks;K. Ell;R. M. Wright
本研究的目的是测试的假设，长期输注血管紧张素II（ANG II）的兔子转移或重置压力反射控制的心率更高的压力水平，通过一种机制，是独立的高血压的产生。通过首先输注逐渐增加剂量的硝普钠（3、6、12、24和48 μ g.kg-1 x min-1）以降低血压，然后增加剂量的苯肾上腺素（0.5、1、2、4和8 μ g.kg-1 x min-1）以升高血压，评估动脉压和心率之间的压力反射关系。静脉输注ANG II（20 ng.kg-1 x min-1）两周后，血浆ANG II水平从9 +/- 1增加到146 +/- 24 pg/ml（P < 0.05），动脉压从62 +/- 2增加到95 +/- 2 mmHg（P < 0.05），心率短暂增加。压力感受性反射在ANG II输注30 min和1、3、7、9和14 d后转移到更高的压力水平。在第1、7和14天的ANG II输注停止后30分钟，动脉压降低，压力感受器反射移回到对照，表明ANG II是产生重置所必需的。然而，当ANG II输注继续进行，而动脉压降低30分钟，在第3和第9天输注硝普钠，动脉压和心率之间的压力反射关系仍然定位在一个较高的压力水平。（250字处删节）
The purpose of this study was to test the hypothesis that chronic infusion of angiotensin II (ANG II) in rabbits shifts or resets baroreflex control of heart rate to a higher pressure level via a mechanism that is independent of the hypertension that is produced. The baroreflex relationship between arterial pressure and heart rate was assessed by first infusing progressively increasing doses of nitroprusside (3, 6, 12, 24, and 48 micrograms.kg-1 x min-1) to lower pressure and then increasing doses of phenylephrine (0.5, 1, 2, 4, and 8 micrograms.kg-1 x min-1) to raise pressure. Two weeks of intravenous ANG II infusion (20 ng.kg-1 x min-1) increased plasma ANG II levels from 9 +/- 1 to 146 +/- 24 pg/ml (P < 0.05), increased arterial pressure from 62 +/- 2 to 95 +/- 2 mmHg (P < 0.05), and transiently increased heart rate. The baroreflex was shifted to a higher pressure level after 30 min and 1, 3, 7, 9, and 14 days of ANG II infusion. Thirty minutes after the ANG II infusion on days 1, 7, and 14 was stopped, arterial pressure decreased, and the baroreflex shifted back to control, indicating that ANG II was required for the resetting that was produced. However, when the ANG II infusion was continued and arterial pressure was instead reduced for 30 min by infusing nitroprusside on days 3 and 9, the baroreflex relationship between arterial pressure and heart rate remained positioned at a higher pressure level.(ABSTRACT TRUNCATED AT 250 WORDS)