BLOOD PRESSURE REGULATION DURING PREGNANCY

描述：压力感受器反射功能是在 包括类固醇激素在内的多种因素的影响。 在 怀孕时，压力感受器反射减弱， 在怀孕后期，动物无法保持压力， 在出血期间。 由于出血是分娩中的常见现象 和交付，理解这一观察的重要性是 值得注意。 本提案中有待检验的假设 这种缺陷发生在大脑或大脑的传出部分， 反射通路，而传入通路没有改变。意识 将对兔子进行研究，以确定交感神经活动是否 妊娠动物在出血期间的含量较少。同情心的评价 活动包括，肾神经记录和区域阻力， 血浆儿茶酚胺、总去甲肾上腺素和肾去甲肾上腺素溢出，以及 肾上腺和神经节酪氨酸羟化酶mRNA水平。 单个动脉压力感受性纤维和传出神经的反应性 对主动脉减压神经的刺激的反应将是 测定离体阻力血管的血管舒张反应 也要评估。怀孕期间上述变化的时间， 将研究泌乳。

DESCRIPTION: Baroreceptor reflex functioning is under the influence of several factors including steroid hormones. In pregnancy, there is an attenuation of the baroreceptor reflex such that in late pregnancy, animals are unable to maintain pressure during hemorrhage. Since hemorrhage is a common occurrence in labor and delivery, the importance of understanding this observation is noteworthy. The hypothesis to be tested in the current proposal is that this deficit occurs in the brain or efferent part of the reflex pathway whereas the afferent pathway is not altered. Conscious rabbits will be studied to determine if sympathetic activity is less in pregnant animals during hemorrhage. Assessments of sympathetic activity include, renal nerve recordings and regional resistances, plasma catecholamines, total and renal norepinephrine spillover, and adrenal and ganglionic levels of tyrosine hydroxylase mRNA. Responsiveness of single arterial baroreceptor fibers and efferent responses to stimulation of the aortic depressor nerve will be determined. Vasodilator responses of isolated resistance vessels will also be assessed. The timing of the above changes during pregnancy and lactation will be studied.