ACUTE BARORECEPTOR RESETTING: NORMOTENSION AND HYPERTEN

动脉压力感受器在血管紧张素转换酶的调节中起重要作用 急性心血管病患者的交感神经活动与动脉血压 应激，如出血和处于病理生理状态，如 高血压。血压升高时动脉压力感受器的激活 动脉压引起交感神经活动的反射性抑制 对动脉压升高的缓冲。动脉水平 这些感受器发射的压力和它们的敏感性 因此，由压力升高引起的激活是决定 动脉血压的神经调节。例如，在高血压 国家，这些压力感受器被“重置”，以便它们发射在更高的 压力和他们的敏感度降低，有助于持续 动脉血压升高。 这种重新设置的现象可能会在临时提升中得到演示 在10-15分钟内控制动脉压(急性重置)。这个 这些研究的目的是检查：1)所涉及的基本机制 在动脉压力感受器急性重置现象中： 具体地说，机械(粘弹性)变化的贡献 颈动脉窦区对压力感受器重置的特性与 受体膜可能的变化的贡献；(2) 重置对传出交感神经活动的影响 “中心重置”相对于外围重置的可能作用 已知发生在压力感受器水平；以及3)电位 “急性重置”在高血压反射控制中的重要性 动物。 为了评估外围设备重置的机制(S)，两者 多纤维和单单位传入颈动脉压力感受器放电 在产生或减弱重置的处理期间记录 进程。颈动脉窦直径的测量将与 一些实验中的压力感受器放电。中央机制将是 通过操纵中央传入输入进行检查(刺激 并观察其对传出神经反射控制的影响。 交感神经活动。高血压和高血压病患者的“急性复位” 将对血压正常的兔进行比较，并探索其机制。 这些研究将阐明反射中一种重要现象的作用 对血液循环的神经性控制和基础的许可检查 这种现象的生理学和病理生理学机制 各州。

The arterial baroreceptors play a major role in the regulation of sympathetic activity and of arterial blood pressure in acute cardiovascular stresses such as hemorrhage and in pathophysiologic states such as hypertension. Activation of the arterial baroreceptors during a rise in arterial pressure provokes a reflex inhibition of sympathetic activity and a buffering of the rise in arterial pressure. The level of arterial pressure at which these receptors will fire and the sensitivity of their activation by the rise in pressure is therefore an important determinant of the neural regulation of arterial pressure. For example, in hypertensive states, these baroreceptors are "reset" so that they fire at a higher pressure and their sensitivity is reduced, contributing to the sustained elevation of arterial pressure. This phenomenon of resetting may be demonstrated with temporary elevations of arterial pressure over a period of 10-15 minutes (acute resetting). The purpose of these studies is to examine: 1) the basic mechanisms involved in the phenomenon of acute resetting of arterial baroreceptors: specifically, the contribution of changes in mechanical (viscoelastic) properties of the carotid sinus region to baroreceptor resetting versus the contribution of possible changes in the receptor membrane; (2) the influence of the resetting on efferent sympathetic activity and the possible role of "central resetting" versus the peripheral resetting which is known to occur at the level of the baroreceptor; and 3) the potential importance of "acute resetting" in the reflex control in hypertensive animals. In order to assess the mechanism(s) of peripheral resetting, both multifiber and single unit afferent carotid baroreceptor discharge will be recorded during treatments that produce or attenuate the resetting process. Diameter of the carotid sinus will be measured simultaneous with baroreceptor discharge in some experiments. Central mechanisms will be examined by manipulating the central afferent input (stimulation of afferent nerves) and observing the effects on reflex control of efferent sympathetic nerve activity. "Acute resetting" in hypertensive and normotensive rabbits will be compared and the mechanisms explored. These studies will clarify the role of an important phenomenon in reflex neurogenic control of the circulation and permit examination of the basic mechanisms involved in this phenomenon in physiologic and pathophysiologic states.