Brooks V L, Keil L C
Department of Physiology, Oregon Health Sciences University, Portland 97201-3098.
Endocrinology. 1994 Nov;135(5):1894-901. doi: 10.1210/endo.135.5.7956910.
This study was performed to test the hypothesis that reflex increases in heart rate, PRA, and plasma concentrations of vasopressin, angiotensin-II, ACTH, and cortisol are reduced during pregnancy. The hypothesis was tested by measuring, in pregnant and nonpregnant conscious dogs, changes in arterial and atrial pressures, heart rate, and plasma hormone concentrations during 30-min infusions of three doses of nitroprusside (1, 2, and 4 micrograms/kg.min). Between-group differences were determined by comparing the relationships between arterial or atrial pressure and plasma hormone concentrations. Hypotension-induced increases in heart rate and plasma levels of vasopressin, ACTH, and cortisol were blunted when the dogs were pregnant. In contrast, reflex increases in PRA and angiotensin-II were increased. These results indicate that the activity of the baroreceptor reflex is altered during pregnancy in dogs.
孕期心率、肾素活性（PRA）以及血管加压素、血管紧张素 II、促肾上腺皮质激素（ACTH）和皮质醇的血浆浓度的反射性增加会降低。通过在怀孕和未怀孕的清醒犬中测量静脉输注三种剂量硝普钠（1、2 和 4 微克/千克·分钟）30 分钟期间动脉和心房压力、心率以及血浆激素浓度的变化来验证该假设。通过比较动脉或心房压力与血浆激素浓度之间的关系来确定组间差异。当犬处于怀孕状态时，低血压引起的心率以及血管加压素、ACTH 和皮质醇血浆水平的增加会减弱。相反，PRA 和血管紧张素 II 的反射性增加则增强。这些结果表明，犬在孕期压力感受器反射的活性会发生改变。
