Effects of central infusion of ANG II and losartan on the cardiac baroreflex in rabbits

被引:28
作者
Gaudet, E [1 ]
Godwin, SJ [1 ]
Head, GA [1 ]
机构
[1] Baker Med Res Inst, Neuropharmacol Lab, Melbourne, Vic 8008, Australia
来源
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY | 2000年 / 278卷 / 02期
关键词
blood pressure; angiotensin type 1 receptors; fourth ventricular administration; long-term infusion;
D O I
10.1152/ajpheart.2000.278.2.H558
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
The effect of chronic activation or inhibition of central ANG II receptors on cardiac baroreflex function in conscious normotensive rabbits was examined. Animals received a fourth ventricular (4V) infusion of ANG II (30 and 100 ng/h), losartan (3 and 30 mu g/h), or Ringer solution (2 mu l/h) for 2 wk. After 1 and 2 wk, ANG II (100 ng/h) decreased cardiac baroreflex gain by 20 and 37%, respectively (P = 0.015), whereas losartan (30 mu g/h) increased baroreflex gain by 24 and 58%, respectively (P = 0.02). Within 1 wk of the end of the infusions, cardiac baroreflex gain had returned to control. Ringer solution or the lower doses of ANG II or losartan did not modify the cardiac baroreflex function. Blood pressure and heart rate were not altered by any treatment, nor was their variability affected. These data demonstrate a novel long-term modulation of cardiac baroreflexes by endogenous ANG II that is independent of blood pressure level.
引用
收藏
页码:H558 / H566
页数:9
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