DIFFERENTIAL BARORECEPTOR REFLEX MODULATION BY CENTRALLY INFUSED ANGIOTENSIN PEPTIDES
DIFFERENTIAL BARORECEPTOR REFLEX MODULATION BY CENTRALLY INFUSED ANGIOTENSIN PEPTIDES
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DOI：
10.1152/ajpregu.1992.263.1.r89
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发表时间：
1992-07-01
影响因子：
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通讯作者：
SANTOS, RAS
中科院分区：
文献类型：
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作者：
CAMPAGNOLESANTOS, MJ;HERINGER, SB;SANTOS, RAS
本研究观察了清醒大鼠侧脑室（icv）和静脉（iv）注射血管紧张素（ANG）-（1-7）、ANG Ⅲ和ANG Ⅱ对压力感受器控制心率（BHR）的影响。 在以3 nmol.7.5-mu-1 -1.h-1的速率icv输注ANG II（n = 10）、ANG III（n = 9）、ANG-（1-7）（n = 9）或盐水（n = 9）之前和1和3 h内，通过静脉推注苯肾上腺素或硝普钠引起HR的反射变化。 在另一组动物（n = 23）中，以0.7ml/h的速率静脉输注相同量的ANG肽。 以每分钟心跳数为单位的HR变化与平均动脉压（MAP，mmHg）变化的平均比率用作BHR敏感性的指标。 ANG II和ANG III使MAP基础水平显著升高，但仅在输注（iv或icv）的第一个小时内。 未观察到基线HR的显著变化。 ANG-（1-7）和生理盐水输注不改变HR或MAP的基础水平（iv或icv）。 ANG II（iv和icv）和ANG III（icv）引起BHR对反射性心动过缓的敏感性显著降低。 与此相反，icv输注ANG-（1-7）诱导BHR对反射性心动过缓的敏感性显著增加（输注前为-3.0 +/-0.3，1 h和-2.8 +/-0.1次/min-1.mmHg-1，3 h vs.-2.1 +/-0.2次/min-1.mmHg-1）。 静脉输注ANG-（1-7）对BHR对MAP升高或降低的敏感性均无影响。 ANG肽均未引起反射性心动过速的变化。 生理盐水输注（icv或iv）未引起BHR敏感性的任何变化。 这些结果显示ANG肽对BHR的调节的不同作用，表明这些肽可以在血压的中枢控制中表达选择性生物学作用。
The present study was designed to investigate the effect of intracerebroventricular (icv) and intravenous (iv) infusion of angiotensin (ANG)-(1-7), ANG III, and ANG II on the baroreceptor control of heart rate (BHR) in conscious rats. Reflex changes in HR were elicited by bolus iv injection of either phenylephrine or sodium nitroprusside before and within 1 and 3 h of icv infusion of ANG II (n = 10), ANG III (n = 9), ANG-(1-7) (n = 9), or saline (n = 9) at a rate of 3 nmol.7.5-mu-l-1.h-1. In another group of animals (n = 23), iv infusion of the same amount of ANG peptides was carried out at a rate of 0.7 ml/h. The average ratio of changes in HR in beats per minute and changes in mean arterial pressure (MAP, mmHg) was used as an index of BHR sensitivity. ANG II and ANG III produced a significant increase in the basal levels of MAP, but only during the first hour of infusion (iv or icv). No significant changes in baseline HR were observed. ANG-(1-7) and saline infusion did not change basal levels of HR or MAP (iv or icv). ANG II (iv and icv) and ANG III (icv) caused a significant decrease in the BHR sensitivity for reflex bradycardia. In contrast, icv infusion of ANG-(1-7) induced a significant increase in BHR sensitivity for reflex bradycardia (-3.0 +/- 0.3, 1 h, and -2.8 +/- 0.1 beats.min-1.mmHg-1, 3 h vs. -2.1 +/- 0.2 beats.min-1.mmHg-1, before infusion). Intravenous infusion of ANG-(1-7) had no effect on the BHR sensitivity for either increases or decreases of MAP. None of the ANG peptides produced changes in reflex tachycardia. Saline infusion (icv or iv) did not produce any change in BHR sensitivity. These results show a differential effect of the ANG peptides on the modulation of the BHR, indicating that these peptides can express selective biological actions in the central control of blood pressure.