ALTERED VASCULAR SMOOTH MUSCLE IN HYPERCHOLESTEROLEMIA

描述：（改编自摘要）提出的假设 研究表明，胆固醇的富集改变了 质膜，这反过来又改变了阳离子通量和细胞质 离子浓度，从而触发改变血管舒缩和细胞 增殖 这些研究将联合收割机在离体动脉中的研究， 正常和喂食胆固醇的兔子主动脉，从动脉中分离的细胞， 和培养的平滑肌和内皮。 目标1将决定 饮食性动脉粥样硬化对基础和激动剂激活的 跨膜Ca++、K+和Na++运动和游离胞质水平。 离子 将在离体动脉中测定流量、细胞溶质钙水平 将在具有fura-2、胞质K+和Na+的分散细胞中测定 水平将从离子的后推法估计到零时间 外排数据 离子的变化将与血管活性相关 对激动剂和钾通道激活剂的反应。 比较将 在培养的细胞中制造，在那里可以获得更纯的膜制备物。 在 此外，微血管对缺血和K+反应的变化 Langendorff兔心脏中的激活剂以及血压 将研究麻醉家兔的反应。 目标2将衡量 将评估膜脂质、流动性，并由合作者评估 膜结构的X射线衍射。 这些参数将 与目标1中的离子通量数据相关。 目标3将审查 从正常和高胆固醇血症中获得的LDL的潜在作用 受试者（以及修饰的LDL）的能力，导致类似的变化 离子通量和膜结构。 目标4将确定机制 负责增加血管细胞的增殖， 测定钙通道拮抗剂的效力并进行 平行离子通量测量，以及确定的影响， 来自富含胆固醇的细胞的条件培养基。

DESCRIPTION: (adapted from the abstract) The hypothesis of the proposed studies is that cholesterol enrichment alters the structure and function of the plasma membrane which, in turn, alters cation fluxes and cytoplasmic ion concentrations, thereby triggering altered vasomotion and cell proliferation. The studies will combine studies in isolated arteries from normal and cholesterol-fed rabbit aorta, isolated cells from the arteries, and cultured smooth muscle and endothelium. Aim 1 will determine the effects of dietary atherosclerosis on basal and agonist activated transmembrane Ca++, K+, and Na++ movements and free cytosolic levels. Ion fluxes will be determined in isolated arteries, cytosolic calcium levels will be determined in dispersed cells with fura-2, cytosolic K+ and Na+ levels will be estimated from back extrapolation to zero time from the ion efflux data. Changes in the ions will be correlated to vasoactive responses to agonists and potassium channel activators. Comparisons will be made in cultured cells where purer membrane preps will be available. In addition, changes in microvascular responses to ischemia as well as to K+ activators in the Langendorff rabbit heart as well as blood pressure responses in the anesthetized rabbit will be studied. Aim 2 will measure membrane lipids, fluidity will be assessed, and a collaborator will assess membrane structure by x-ray diffraction. These parameters will be correlated with the ion flux data in aim 1. Aim 3 will examine the potential role of LDL obtained form normal and hypercholesterolemic subjects (as well as modified LDL) for its ability to cause similar changes in ion fluxes and membrane structure. Aim 4 will determine the mechanisms responsible for the increased proliferation of vascular cells by determining the potency of calcium channel antagonists and performing parallel ion flux measurements, as well as determining the influence of conditioned media from cells enriched with cholesterol.