RENAL GLOMERULAR HEMODYNAMICS--NEURAL CONTROL MECHANISM

肾小球血流动力学--神经控制机制

• 批准号: 3472576
• 负责人: JOHN T FLEMING
• 金额: $ 9.97万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 1995-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3472576
• 关键词: adrenergic receptor; angiotensin II; calcium channel blockers; calcium flux; glomerular filtration; kidney circulation; laboratory rat; microcirculation; normetanephrine; renal hypertension; vascular resistance; vasoconstriction

The long-term objective of the research is to elucidate the mechanisms which mediate and regulate renal vascular (preglomerular and postglomerular) responses to increase in neural activity. The elucidation of normal control mechanisms will help to identify altered mechanisms in pathological conditions associated with elevated renal nerve activity and loss of kidney function (hypertension). The proposed research will address the following concepts: 1) Increases in renal nerve activity differentially nerve activity , constriction of specific vessels is induced by norepinephrine, alone or in combination with angiotensin II, (3) Different alpha-1 adrenergic receptor subtypes mediate norepinephrine constriction of different renal and (4) Constriction of large arteries versus small arterioles to nerve stimulation is mediated by calcium derived from different sources (extracellular versus intracellular). These concepts will be addressed by observing the in vivo renal microcirculation of the rat hydronephrotic kidney. The diameters of preglomerular vessels, glomerular capsules and capillaries, and efferent arterioles will be measured directly from a calibrated television monitor during direct stimulation of the renal nerve (at varing frequencies or duration) or during reflex-induced increase in renal nerve activity. Stimulation- response curves will be generated for each vascular site to compare relative vessel reactivity. Glomerular hemodynamic changes will be assessed by direct measurements of glomerular capillary pressure (servo- null system)and blood flow (optical doppler RBC velocimeter). To determine the role of norepinephrine to constrict select vessels via specific receptors, stimulation-response curves will repeated after blockade of alpha-la or alpha-1b adrenergic receptors. Similarly, the role of circulating angiotensin II receptor blockade. Shifts in the stimulation responses curves agonist to cause selective constriction. Attenuation of constrictor responses by calcium entry blockers will reflect the dependency of different vessels on influx of extracellular calcium or intracellular calcium release for constriction to nerve stimulation.

这项研究的长期目标是阐明 其介导和调节肾血管（肾小球前和 肾小球后）对神经活动增加的反应。 阐明 正常的控制机制将有助于确定改变的机制， 与肾神经活动升高相关的病理状况， 肾功能丧失（高血压）。 拟议的研究将解决 以下概念：1）肾神经活动增加 不同的神经活动，特定血管的收缩被诱导， 去甲肾上腺素，单独或与血管紧张素II联合，（3） 不同的α-1肾上腺素能受体亚型介导去甲肾上腺素 （4）大动脉狭窄 与小动脉相比，神经刺激由钙源性介导 从不同的来源（细胞外与细胞内）。 这些 概念将通过观察体内肾微循环来解决 大鼠肾积水的肾脏。 肾小球前血管直径， 肾小球囊和毛细血管，以及传出小动脉将 直接从校准的电视监视器测量， 刺激肾神经（以不同的频率或持续时间）或 在反射引起的肾神经活动增加期间。 刺激- 将生成每个血管部位的响应曲线，以进行比较 相对血管反应性。 肾小球血流动力学变化将 通过直接测量肾小球毛细血管压（servo- 零系统）和血流（光学多普勒RBC流速计）。 以确定 去甲肾上腺素通过特异性收缩选择血管的作用 受体，阻断后刺激-反应曲线将重复 α-1a或α-1b肾上腺素能受体。 同样， 循环血管紧张素II受体阻滞剂。 刺激的变化 反应曲线激动剂引起选择性收缩。 衰减 钙离子进入阻滞剂引起的收缩反应将反映依赖性 对细胞外钙离子或细胞内钙离子内流的影响 钙释放用于神经刺激的收缩。