CHARACTERIZATION OF MAST CELL HISTAMINE

肥大细胞及其同系物，嗜碱性细胞和粘膜细胞 肥大细胞，是一系列的主要效应细胞类型， 炎症反应，如花粉热和哮喘。 当 通过表面结合免疫球蛋白E的交联刺激， 肥大细胞释放组胺， 胞质颗粒 尽管存储的重要性 组胺的分泌颗粒，很少有人知道在 分子水平上的组胺的颗粒内状态或 颗粒内环境的性质。 这部分是由于 缺乏工具，可以检查完整的细胞， 分子水平。 本研究的目的是（1）表征 肥大细胞分泌颗粒内环境 相对于pH值，水含量和流动性， 颗粒内组胺，（2）确定颗粒的变化 关于pH值和组胺流动性，发生在 在胞吐过程中颗粒的挤出，以及（3）完全 表征颗粒与组胺的结合， 亲和常数和结合位点。 这些目标将 通过使用非侵入性1H核磁共振来完成 (NMR)光谱法检查完整肥大细胞中的组胺， 在组胺颗粒和组胺糖胺聚糖模型中 系统. 组胺在完整细胞和肥大细胞中的流动性 在刺激后被抑制， 将由组胺质子的弛豫时间确定。 颗粒与组胺结合的亲和常数， 糖胺聚糖将由化学位移确定， 强度测量。 将通过以下方法测定颗粒内pH值： 使用添加的咪唑作为NMR pH指示剂，而小的， 中性、颗粒可渗透分子，例如甲醇， 用作水量报告器。 预计这些 研究将有助于增加对肥大细胞的理解， 行为，这是必不可少的故意扰动的 用于治疗目的的分泌过程。

Mast cells and their homologues, the basophil and the mucosal mast cell, are the primary effector cell type in a range of inflammatory reactions, such as hayfever and asthma. When stimulated by cross-linking of surface bound immunoglobulin E, mast cells release performed histamine from membrane-enclosed, cytoplasmic granules. Despite the importance of the storage of histamine in the secretory granules, little is known at the molecular level about the intragranular state of histamine or the nature of the intragranular environment. This is due in part to the lack of tools with which intact cells can be examined at the molecular level. It is the aim of this research (1) to characterize the intragranular environment of mast cell secretory granules with respect to pH, water content and the mobility of intragranular histamine, (2) to identify the changes in granules with respect to pH and histamine mobility that occur prior to extrusion of the granule during exocytosis, and (3) to fully characterize the binding of histamine by granules in terms of affinity constants and binding sites. These objectives will be accomplished by using noninvasive 1H nuclear magnetic resonance (NMR) spectroscopy to examine histamine in intact mast cells and in histamine-granule and histamine-glycosaminoglycan model systems. The mobility of histamine in intact cells, in mast cells which have been arrested following stimulation, and in granules will be determined from relaxation times for histamine protons. Affinity constants for the binding of histamine by granules and glycosaminoglycans will be determined from chemical shift and intensity measurements. Intragranular pH will be determined by using added imidazole as an NMR pH indicator, while a small, neutral, granule permeable molecule, such as methanol, will be used as a reporter of water volume. It is anticipated that these studies will contribute to an increased comprehension of mast cell behavior which is essential for deliberate perturbation of the secretory process for therapeutic purposes.