ARTERIAL STIFFNESS & AGE--EFFECTS ON CIRCULATORY CONTROL

描述(改编自申请者摘要)：第一个奖项将 探讨心血管功能降低与心血管功能升高的关系 血管硬度与年龄的关系以及对1995年国家研究所的反应 关于老龄化计划公告(PA-95-074)。与年龄相关的强直 颈动脉压力感受区将有效地使压力感受性反射脱敏，因为 压力感受器对压力相关的拉伸有反应。动脉 压力感受性反射是迷走神经和迷走神经平均水平的关键决定因素 交感神经流出；因此，较低的迷走神经和较大的交感神经流出 与心血管疾病相关的可能是钝化的压力反射 由于血管僵硬增加。尽管动脉僵硬增加 随着年龄的增长，它与有氧能力呈负相关，与年龄无关。 因此，慢性有氧训练可能有助于维持压力感受器反射的自主神经。 通过减轻与年龄相关的动脉僵硬来控制循环。这个 这项提案的具体目的是确定：1)是否与年龄有关 压力感受性反射对迷走神经和交感神经流出的控制减少 与更大的颈动脉僵硬有关，2)压力感受器反射与年龄相关的下降 小颈动脉减少对迷走神经和交感神经流出的控制 与有氧健身有关的僵硬，以及3)有规律的 老年人有氧运动训练增加对压力感受器反射的控制 由于颈动脉僵硬程度降低，迷走神经和交感神经流出。它是 假设与年龄相关的压力感受性反射循环减少 与颈动脉僵硬增加和基础状态改变相关的控制 自主神经流出可以通过运动训练来逆转。为了实现这些目标 AIMS，最先进的神经生理学和超声检查手段将 被要求评估自主神经流出相对于真实的压力反射增益 压力感受器激活刺激改变颈动脉的大小。年青的 (20-30岁)年龄更大(60-80岁)男性和女性将接受严格的筛查 确定老化过程本身的影响(与 疾病、不活动等)压力反射功能，基础自主神经流出， 和颈动脉僵硬。与年龄相关的下降的可能逆转通过 有氧运动训练将进行横断面和 纵向的。调查者指出，这些研究是独一无二的； 没有数据表明气压感官维度的变化与 人类心血管自主神经流出的同步变化。他觉得 尽管数据表明颈动脉僵硬在其中起着重要作用 在压力感受器反射功能中，压力感受器的僵硬是否增加是未知的。 区域导致与年龄相关的压力反射增益的减少，最终 减少迷走神经，增加交感神经流出。此外，他觉得 有氧健身是否会调节这些与年龄有关的影响尚不清楚。他 声明这些信息对于理解钝化的压力反射是至关重要的 血管僵硬的次要功能是衰老的管道 损害自主循环控制，增加心血管疾病 发病率。

DESCRIPTION (Adapted from the Applicant's Abstract): This FIRST award will investigate the relation of decreased cardiovascular function to increased vascular stiffness with age and is responsive to a 1995 National Institute on Aging program announcement (PA-95-074). Age-related stiffening of carotid barosensory areas would effectively desensitize the baroreflex since baroreceptors are responsive to pressure-related stretch. The arterial baroreflex is a key determinant of the mean level of both vagal and sympathetic outflows; thus, the lower vagal and greater sympathetic outflows associated with cardiovascular diseases may result from blunted baroreflexes due to increased vascular stiffness. Though arterial stiffness increases with age, it is negatively related to aerobic capacity regardless of age. Thus, chronic aerobic training may help to maintain baroreflex autonomic circulatory control by mitigating age-related arterial stiffening. The specific aims of this proposal are to determine if: 1) age-related decreases in baroreflex control of vagal and sympathetic outflows are related to greater carotid stiffness, 2) age-related declines in baroreflex control of vagal and sympathetic outflows are reduced by lesser carotid stiffness associated with aerobic fitness, and 3) a program of regular aerobic exercise training in older humans increases baroreflex control of vagal and sympathetic outflows due to decreased carotid stiffness. It is hypothesized that the age-related reductions in baroreflex circulatory control associated with increased carotid stiffness and altered basal autonomic outflow can be reversed by exercise training. To fulfill these aims, state-of-the-art neurophysiologic and ultrasonographic measures will be made to assess baroreflex gain of autonomic outflow relative to the true stimulus for baroreceptor activation changes in carotid dimensions. Young (20-30 yr.) and older (60-80 yr.) men and women will be rigorously screened to determine the influence of the aging process per se (as opposed to disease, inactivity, etc.) on baroreflex function, basal autonomic outflow, and carotid stiffness. The possible reversal of age-related declines by aerobic exercise training will be assessed both cross-sectionally and longitudinally. The investigator indicates that these studies are unique; that there are no data which relate changes in barosensory dimensions to concurrent changes in cardiovascular autonomic outflow in humans. He feels that despite data indicating that carotid stiffness plays a significant role in baroreflex function, it is unknown if increased stiffness in barosensory areas results in the age-related reduction in baroreflex gain, ultimately decreasing vagal and increasing sympathetic outflow. Further, he feels that it is unknown if aerobic fitness modulates these age-related effects. He states that this information is crucial to understand if blunted baroreflex function secondary to vascular stiffening is the conduit by which aging compromises autonomic circulatory control and increases cardiovascular morbidity.