PERICYTES AND NEURORETINAL MICROVASCULAR PHYSIOLOGY

周细胞和神经视网膜微血管生理学

• 批准号: 2163426
• 负责人: DOUGLAS R ANDERSON
• 金额: $ 16.87万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2163426
• 关键词: acidity /alkalinity; calcium flux; carbon dioxide tension; extracellular; glaucoma; homeostasis; microcirculation; retina circulation; tissue /cell culture

The blood flow in the optic nerve head is normally autoregulated, little affected by the level of intraocular pressure (IOP). Such regulation may be achieved through response to tissue levels of oxygen and carbon dioxide, which reflect the balance between local tissue metabolism and the volume of local blood flow. Hypothetically in glaucoma this regulation is faulty in the optic nerve head, permitting ischemic damage when the circulation is challenged by elevation of IOP. Only a little is known of the local physiologic events by which autoregulation is achieved, but nothing about how it may become faulty, or how faulty autoregulation might be corrected. Vascular smooth muscle of arteries and arterioles and precapillary sphincters have considerable influence on distribution of blood flow to various tissue regions. We hypothesize that capillaries may provide local fine tuning of blood flow, at least in some tissues. If capillaries participate in local control of blood flow, it may be achieved through pericytes, contractile cells whose function is not known, found in the walls of capillaries, especially in the central nervous system, including retina and optic nerve. In this project we plan to study the contractile response of pericytes grown in cell culture to metabolic signals that may permit them to participate in local control of the blood flow. The signals to be studied first are changes in carbon dioxide levels and the change in pH that accompanies changes in carbon dioxide levels. Responses to be observed are cell contraction, changes in intracellular pH, and changes in intracellular free calcium concentration.

视神经乳头的血流通常是自动调节的，很少 受眼压（IOP）水平的影响。 此类监管可能 通过对组织中氧和碳水平的反应来实现 二氧化氮，反映局部组织代谢与代谢之间的平衡 局部血流量。 假设在青光眼中 视神经头的调节有缺陷，导致缺血性损伤 当循环受到眼压升高的挑战时。 对局部生理事件知之甚少 实现了自动调节，但没有说明它如何可能出现故障， 或者如何纠正错误的自动调节。 血管平滑肌 动脉和小动脉以及毛细血管前括约肌有相当大的 影响各个组织区域的血流分布。 我们 假设毛细血管可以提供血流的局部微调， 至少在某些组织中。 如果毛细血管参与局部血流控制，则可能是 通过周细胞、收缩细胞来实现，其功能不是 已知，存在于毛细血管壁中，特别是在中央 神经系统，包括视网膜和视神经。 在这个项目中我们 计划研究细胞培养中生长的周细胞的收缩反应 代谢信号可能允许它们参与局部控制 的血流量。 首先要研究的信号是碳的变化 二氧化碳含量和 pH 值随碳变化而变化 二氧化碳水平。 观察到的反应是细胞收缩、变化 细胞内pH值和细胞内游离钙的变化 专注。