Racial Differences--Stress Induced Homeostatic Response

本研究的总体目标是更全面地了解应激引起的生理变化在原发性高血压民族差异发展中的作用。对压力的生理反应是一个动态的过程。它包括对压力源本身的反应和使身体进入内稳态的生理反应。绝大多数的研究都集中在应激时的生理反应上，而应激后的稳态变化在很大程度上被忽视了。关于群体差异的信息很少。该建议的一般假设如下：与高加索人相比，非洲裔美国人在压力期间和之后表现出较慢的尿钠，并伴有较大的血管收缩。这将导致应激后血压升高的时间延长，使这些个体暴露于血压负荷增加，从而导致终末器官变化的过早发展。因此，本研究的目的是：1)对比非裔美国人和白人受试者在60分钟应激期之前、期间和之后2小时的血流动力学调节；2)非裔美国人和白人受试者在手术过程中的激素调节对比；3)非裔美国人与白人受试者在手术过程中Na+处理水平的对比；4)确定恢复期靶器官变化指标与血压变化之间的关系。拟议的研究将通过a)首次确定与反应相关的激素机制，大大增加对内部平衡过程受损的潜在因素和重要性的最低认识；b)首次通过将反应与靶器官变化联系起来确定其临床意义。

The overall goal of this study is to obtain a more complete understanding of the role that physiologic changes induced by stress play in the development of ethnic differences in essential hypertension. The physiologic response to stress is a dynamic process. It includes the response to the stressor per se AND the physiologic response, which bring the body into homeostasis. The vast majority of research has focused on the physiologic response during stress while homeostatic changes following stress have largely been ignored. There is very little information about group differences. The general hypothesis of this proposal is as follows: African-Americans compared to Caucasians show slower natriuresis during and following the stress coupled with greater vasoconstriction. This will result in an extended period of elevated blood pressure following stress, exposing these individuals to an increased BP load, which leads to the premature development of end organ changes. Therefore, the aims of this study are: 1) contrast hemodynamic regulation in African-American and Caucasian subjects before, during, and two hours following a 60 minute stress period; 2) contrast hormonal regulation in African-American and Caucasian subjects during the procedure; 3) contrast levels of Na+ handling between African-American and Caucasian subjects during the procedure; 4) determine the relationship between measures of target organ change and BP changes during the recovery period. The proposed study will add considerably to the minimal knowledge of the factors underlying, and significance of, an impaired homeostatic process by a) for the first time identifying hormonal mechanism associated with the response; and b) for the first time determining the clinical significance of the response by relating it to target organ changes.