Total autonomic blockade eliminates the attenuated pressor response to angiotensin II in pregnant rats.
Total autonomic blockade eliminates the attenuated pressor response to angiotensin II in pregnant rats.
复制标题
完全自主神经阻断消除了妊娠大鼠对血管紧张素 II 的减弱的升压反应。
DOI：
10.1152/ajpregu.1993.265.6.r1270
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Barron,WM
中科院分区：
文献类型：
--
作者：
Hines,T;Lindheimer,MD;Barron,WM
Pressor responses to angiotensin II (ANG II) are markedly attenuated in reflex-intact pregnant animals, a phenomenon widely attributed to intrinsic changes in vascular reactivity. To test the hypothesis that gestational augmentation of neural reflex activity contributes importantly to this phenomenon, changes in mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR) were compared during constant infusion (25-400 ng.kg-1.min-1) of ANG II in conscious virgin and pregnant rats, using a model of total autonomic blockade (chlorisondamine chloride and methscopolamine bromide), with restoration of baseline hemodynamics by infusion of norepinephrine. Basal CO was higher and TPR lower in pregnant (CO 121.8 +/- 3.8 ml/min; TPR 0.78 +/- 0.04 mmHg.ml-1.min) compared with virgin (CO 95.9 +/- 3.9 ml/min; TPR 1.05 +/- 0.08 mmHg.ml-1.min) rats (P < 0.005). Pressor responses to ANG II were similar in both groups of reflex-blocked animals due to comparable changes in TPR and CO (not significant by repeated-measures analysis of variance). Other experiments demonstrated that changes in MAP after bolus administration of ANG II did not differ in areflexic virgin and gravid rats. Thus in the absence of autonomic control ANG II has similar effects on systemic resistance in pregnant and nonpregnant rats, suggesting that reflex neural mechanisms contribute significantly to gestational changes in pressor responsiveness. These data further suggest that pregnancy is not accompanied by a generalized decrease in vascular reactivity to all pressor agents.
