ARTERIAL BAROREFLEX FUNCTION WITH AGING

一般认为，动脉压力反射控制和迷走神经 随着年龄的增长（>60岁），心率的控制能力减弱， 人类这些现象被用来解释 在健康老年人中观察到的体位性低血压的发生率 人口然而，最近，我们记录了离散的 颈动脉压力感受器反射对健康人心率的控制60-69 年龄与18-36岁的健康个体没有什么不同 岁的因此，我们假设，离散的主动脉 老年人压力感受器介导的心率反射控制 个人必须妥协。其他研究结果表明，作为 人的年龄增加的颈动脉心脏反射控制 在年轻人中观察到的中枢性低血容量引起的心率 减少了因此，我们进一步假设， 颈动脉压力感受性反射功能与中心血容量的关系 （低血容量或高血容量）在老年受试者（60-75 年）。为了验证这些假设，我们将分离颈动脉和主动脉 正常血容量、低血容量和低血容量期间心率的压力反射控制 高血容量中心血容量，在一项横断面调查中， 18-36岁的成年人和60-75岁的成年人。在 此外，使用功率检查迷走神经对心率的控制 将对所有条件和年龄组进行光谱分析。它 预计获得的数据将为我们提供深入了解 动脉压力感受性反射控制心率改变的机制 老年人在直立状态下。此外，我们希望开发一个模型， 直立性低血压，进一步研究 与年龄相关的直立性低血压增加的机制可能是 进行了我们的长期目标是了解衰老的机制 对人体血容量和血压的神经体液调节， 为使用预防措施提供依据， 老年人的生活质量。

It is generally accepted that arterial baroreflex control and vagal control of heart rate is diminished with increases in age (>60 years) in the human. These phenomena have been used to explain the increased incidence of orthostatic hypotension observed in the healthy older population. More recently, however, we have documented that discrete carotid baroreflex control of the heart rate of healthy individuals 60-69 years of age was no different than that of healthy individuals 18-36 years of age. Therefore, we hypothesize, that the discrete aortic baroreceptor mediated reflex control of heart rate of the older individuals must be compromised. Other findings suggest that as individuals age the augmentation of the carotid-cardiac reflex control of heart rate by central hypovolemia, observed in young adults is diminished. Therefore, we further hypothesize that the interactions of carotid baroreflex function with the status of central blood volume (hypovolemia or hypervolemia) is diminished in older subjects (60-75 years). To test these hypotheses, we will isolate the carotid and aortic baroreflex control of heart rate during euvolemic, hypovolemic and hypervolemic central blood volumes, in a cross-sectional investigation of 18-36 year old adults and 60-75 year old adults of both genders. In addition, examination of the vagal control of heart rate using power spectral analysis will be made across all conditions and age groups. It is anticipated that the data obtained will provide us insight into the mechanism of altered arterial baroreflex control of heart rate of the elderly during orthostasis. Furthermore, we expect to develop a model of orthostatic hypotension upon which further investigations into the mechanisms of the age related increase in orthostatic hypotension can be made. Our long-term objectives are to understand the mechanisms of aging on human neurohumoral regulation of blood volume and blood pressure and to provide the basis for the use of prophylactic measures to enhance the quality of life of the elderly population.