BLOOD PRESSURE CONTROL BY FOREBRAIN & BRAINSTEM NEURONS

前脑控制血压

• 批准号: 3344975
• 负责人: SUSAN M BARMAN
• 金额: $ 12.33万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-30 至 1995-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3344975
• 关键词: autonomic reflex; baroreceptors; brain electrical activity; brain mapping; brain stem; cardiovascular function; cats; efferent nerve; electrophysiology; histology; interneurons; neural information processing; neuroanatomy; neurogenic hypertension; prosencephalon; sympathetic nervous system

The long range goal of this research is to identify electrophysiologically CNS pathways that control sympathetic nerve discharge (SND) and cardiovascular function. The PI has studied these pathways in barbiturate- anesthetized cats in which SND is synchronized into bursts (slow waves) that are locked to the cardiac cycle via the baroreceptor reflex. After baroreceptor-denervation these sympathetic slow waves occur at frequencies varying mainly between 2 and 6 Hz. Others report that in some unanesthetized-decerebrate (UD), urethane-anesthetized, or conscious cats, a 10-Hz rhythm coexists with this 2- to 6-Hz activity. Recent studies in the PI's laboratory confirm the existence of a 10-Hz rhythm in SND of UD, baroreceptor-denervated cats. Key findings of these studies include the following. 1) 10-Hz activity coheres (correlates) strongly among each of the nerves studied (inferior cardiac, vertebral, and renal nerves). 2) Episodes of 10-Hz activity are often followed by increases in arterial pressure, suggesting that this rhythm regulates vasomotor tone. 3) 10-Hz but not 2- to 6-Hz activity is eliminated by a midline sagittal cut of the medulla (0-6 mm rostral to the obex). This occurs without a change in total power in SND, but blood pressure significantly decreases. This suggests that the pattern (10-Hz vs 2- to 6-Hz) rather than just total power in SND regulates the level of blood pressure. 4) The activity of some raphe neurons is synchronized to 10-Hz slow waves in SND. Although this 10-Hz rhythm was described ~ 25 yr ago, no one has yet established its region of origin, properties of central neurons mediating this rhythm, or pathways that relay this activity to sympathetic nerves. Data available suggest that the 10-Hz rhythm is generated in the brainstem. State-of-the- art electrophysiological techniques (spike-triggered averaging, antidromic mapping, and autospectral, coherence, and phase spectral analyses) will be used to address the following aims in experiments on UD cats: 1) to determine the site of origin of this activity, 2) to identify brainstem neurons whose activity is correlated to this rhythm in SND, 3) to determine interconnections of neurons responsible for the 10-Hz rhythm, 4) to assess the functional significance of this rhythm in regulating cardiovascular function, and 5) to assess the effects of central respiratory drive on the frequency of sympathetic nerve slow waves. These studies will determine if the 2- to 6-Hz and 10-Hz components in SND are generated by different brainstem networks, or if the two patterns reflect different physiological states of the same network. These studies will enhance our understanding of the central circuitry responsible for generating resting SND in the absence of the effects of anesthesia.

这项研究的远距离目标是在电生理上识别 控制交感神经排出（SND）和 心血管功能。 PI研究了巴比妥酸酯中的这些途径 麻醉猫，其中SND同步为突发（慢波） 通过压力感受器反射锁定到心脏周期。 后 这些交感的慢波发生在频率下 主要在2至6 Hz之间变化。 其他人报告说 未经动心的脑脑（UD），氨基甲酸酯麻醉或有意识的猫， 10 Hz的节奏与这种2至6 Hz活性共存。 最近的研究 PI的实验室确认在UD的SND中存在10 Hz的节奏， 压力受体受体的猫。 这些研究的主要发现包括 下列的。 1）10-Hz活性耦合（相关）强烈 神经研究（心脏下，椎骨和肾神经）。 2） 10-Hz活性的发作通常随后动脉增加 压力，表明这种节奏调节血管舒缩张力。 3）10-Hz 但是，通过中线矢状切割消除了2至6-Hz的活动 髓质（obex的0-6 mm to）。 发生这种情况而没有改变 SND中的总功率，但血压显着降低。 这 表明图案（10 Hz与2至6 Hz），而不仅仅是总数 SND中的功率调节血压水平。 4）活动 一些Raphe神经元在SND中同步为10-Hz慢波。 虽然 这个10-Hz的节奏是在大约25年前描述的，还没有人确定 起源区域，介导这种节奏的中央神经元的特性，或 将这种活动传达给交感神经的途径。 可用的数据 建议在脑干中产生10 Hz节奏。 最先进的 艺术电生理技术（尖峰触发的平均抗原 映射，自谱，连贯性和相光谱分析）将是 用于解决UD猫实验的以下目的：1） 确定此活动的起源部位，2）确定脑干 活性与SND中的节奏相关的神经元，3） 负责10 Hz节奏的神经元的互连，4） 这种节奏在调节心血管方面的功能意义 功能，5）评估中央呼吸道驱动对 交感神经慢波的频率。 这些研究将确定是否 SND中的2至6-Hz和10 Hz组件由不同的 脑干网络，或两种模式反映不同的生理 同一网络的状态。 这些研究将增强我们的理解 中央电路负责在 缺乏麻醉作用。