ANGIOTENSIN II, VASOPRESSIN AND THE BARORECEPTOR REFLEX

静脉注射血管紧张素II改变压力感受器反射 使心率和血浆中加压素和促肾上腺皮质激素浓度 每一水平的动脉血压都高于正常水平。至 确定AII是否会增加这些荷尔蒙的水平和心率 通过降低来自动脉和低位输入的紧张性抑制效应 压力牵张感受器去神经支配对大鼠脑电活动的影响 将研究血管加压素、ACTH和对ALII的心脏反应。的作用 反应中的最后区域将通过确定 椎管内注入AII或病变后区对患者预后的影响 压力感受器反射的功能。将对压力反射功能进行评估 通过研究血压和三个因素中的每一个之间的关系 参数：心率和全身血管加压素浓度和 ACTH。血压会因输注硝普钠而改变 和苯肾上腺素，或通过出血。 注射加压素似乎也会影响压力感受器反射功能。 增强反射的强度。以确定该区域是否 后遗症介导这一作用，后叶加压素输注对 压力感受性反射对ACTH分泌的控制 将会被研究。后叶加压素输注是否促进反射释放 ACTH的分泌也将被调查。最后，内生性的作用 血管紧张素Ⅱ和加压素在压力感受性反射调节中的作用 输注阻滞剂检查出血和缺水情况。 肾素-血管紧张素系统或血管加压素拮抗剂。

Intravenous infusion of angiotensin II (AII) alters the baroreceptor reflex such that heart rate and plasma concentrations of vasopressin and ACTH are elevated above normal at each level of arterial blood pressure. To determine whether AII increases the levels of these hormones and heart rate by decreasing the tonic inhibitory effect of input from arterial and low pressure stretch receptors, the effect of abroreceptor denervation on the vasopressin, ACTH and cardiac response to AII will be studied. The role of the area postrema in the responses will be investigated by determining the effect of intravertebral infusion of AII or lesions of the area postrema on function of the baroreceptor reflex. Baroreflex function will be assessed by examining the relationship between blood pressure and each of three parameters: heart rate and systemic concentrations of vasopressin and ACTH. Blood pressure will be varied either by infusion of nitroprusside and phenylephrine, or by hemorrhage. Vasopressin infusion also appears to affect baroreflex function by enhancing the strength of the reflex. To determine whether the area postrema mediates this action, the effect of vasopressin infusion on baroreflex control of ACTH secretion in dogs with lesions of this structure will be studied. Whether vasopressin infusion enhances reflex release of ACTH secretion will also be investigated. Finally, the role of endogenous AII and vasopressin in regulation of the baroreceptor reflex during hemorrhage and water deprivation will be examined by infusion of blockers of the renin-angiotensin system or a vasopressin antagonist.