PERMISSIVE ROLE OF PGI-2 IN NEWBORN CEREBRAL CIRCULATION

PGI-2 在新生儿脑循环中的许可作用

• 批准号: 2220719
• 负责人: CHARLES W. LEFFLER
• 金额: $ 21.05万
• 依托单位: UNIVERSITY OF TENNESSEE HEALTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-16 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2220719
• 关键词: acid base balance; carbon dioxide tension; cyclic AMP; electron microscopy; fatty acid metabolism; hemodynamics; histopathology; hypercapnia; microcirculation; muscle function; newborn animals; prostacyclins; radioimmunoassay; radionuclides; radiotracer; receptor binding; respiratory gas level; statistical service /center; swine; vascular smooth muscle; vasodilatation

The research proposed is designed to address the unifying hypothesis that endothelial-derived prostacyclin permits newborn cerebral microvascular smooth muscle to dilate in response to specific stimuli. To test this hypothesis, four specific aims will be pursued using newborn pigs: l) Determine, in vivo, the ability of prostacyclin to restore cerebral vasodilator responses inhibited by indomethacin and by endothelial injury. 2) Examine the relationship between the ability of prostacyclin to restore vasodilation and changes in cyclic nucleotide metabolism. 3) Characterize, in vivo, the relationship between cerebral microvascular endothelial cell prostacyclin synthesis and smooth muscle cAMP in response to increased CO2. 4) Investigate the mechanisms by which prostacyclin modifies cerebral microvascular smooth muscle responses to hypercapnia. To accomplish these aims, techniques allowing investigation of intact cerebral microcirculation and primary culture of cells from newborn pig brain will be employed. Such research will be unique by studying the intact newborn cerebral circulation, isolated components that contribute to control of that circulation, and cocultures of these components to investigate mechanisms of communication. Cranial windows allow observation of cerebral microcirculation, collection of cortical periarachnoid fluid, selective endothelial damage, in vivo, and topical application of treatments and putative permissive agonists and inhibitors. Piglet cerebral microvascular endothelial and smooth muscle cells in primary culture will be used to study the effects of endothelial prostacyclin on smooth muscle cAMP responses to CO2. Effects of stable prostacyclin analogs on cerebral microvascular smooth muscle cAMP responses to CO2 will be evaluated. cAMP produced in response to CO2 by endothelial and vascular smooth muscle cells grown in isolation and together will be measured. To examine the relative contributions of intracellular and extracellular pH to the smooth muscle response to hypercapnia, using piglet cerebral microvascular smooth muscle cells in culture, we will measure cAMP production in response to decreases of pH-i with constant pH-e and in response to reduction of pH-e while maintaining pH-i. Selected potential cellular messenger pathways for involvement in the permissive role of prostacyclin in the microvascular smooth muscle response to hypercapnia will be evaluated. The effect of CO2 on iloprost receptor binding, the contributions of protein phosphorylation to the permissive role of prostacyclin and the kinases and substrates involved will be studied. Since disorders of cerebral circulation are major causes of morbidity and mortality in neonates and can result in lifelong disabilities in survivors better understanding of factors controlling newborn cerebral hemodynamics is badly needed.

提出的研究旨在解决统一的假设，即 内皮衍生的前列环蛋白允许新生儿脑微血管 平滑肌以响应特定的刺激而扩张。测试这个 假设，使用新生猪将追求四个特定目标：l） 在体内确定前列环蛋白恢复脑的能力 血管扩张剂的反应被吲哚美辛抑制和内皮损伤所抑制。 2）检查前列环蛋白恢复能力之间的关系 血管舒张和环状核苷酸代谢的变化。 3）表征， 在体内，脑微血管内皮细胞之间的关系 前列环蛋白的合成和平滑肌训练营，以响应增加 二氧化碳。 4）研究前列环蛋白修饰脑的机制 微血管平滑肌反应对高碳酸盐。完成这些 目的，允许研究完整脑的技术 新生猪脑细胞的微循环和原发性培养将 被雇用。通过研究完整的新生儿，这种研究将是独一无二的 大脑循环，有助于控制的孤立成分 这些成分的循环和共培养 沟通机制。颅窗可以观察大脑 微循环，皮质周围液体的收集，选择性 内皮损害，体内以及治疗的局部应用和 推定的允许激动剂和抑制剂。小猪脑微血管 原发性培养中的内皮和平滑肌细胞将用于 研究内皮前列环素对平滑肌营的影响 对CO2的响应。稳定前列环蛋白类似物对脑的影响 将评估微血管平滑肌营对CO2的反应。营 由内皮和血管平滑肌响应二氧化碳而产生 分别生长并一起测量细胞。检查 细胞内和细胞外pH对光滑的相对贡献 使用仔猪脑微血管平滑的肌肉反应对高碳酸盐 培养中的肌肉细胞，我们将根据 pH-I随恒定pH-E的降低，并响应于pH-E的降低 同时维持ph-i。选定的潜在蜂窝信使通路 参与前列环蛋白在微血管中的允许作用 将评估平滑肌肉对高碳酸血症的反应。二氧化碳的效果 在伊洛前列素受体结合上，蛋白质磷酸化的贡献 前列环蛋白以及激酶和底物的允许作用 涉及的研究将进行研究。由于脑循环疾病是 新生儿发病和死亡率的主要原因，可能导致 幸存者的终身残疾更好地理解因素 迫切需要控制新生儿脑血液动力学。