CHARACTERIZATION OF MAST CELL HISTAMINE

肥大细胞及其同系物、嗜碱性粒细胞和粘膜 肥大细胞是一系列主要的效应细胞类型 炎症反应，如花粉热和哮喘。什么时候 受表面结合的免疫球蛋白E的交联刺激， 肥大细胞从膜包裹的组织中释放组胺， 胞质颗粒。尽管储存食品的重要性 分泌颗粒中的组胺，目前还知之甚少 关于组胺颗粒内状态的分子水平或 粒内环境的性质。这部分归因于 缺乏可用来检查完整细胞的工具 分子水平。本研究的目的是(1)表征 肥大细胞分泌颗粒的颗粒内环境 关于pH值、水分含量和水的流动性 颗粒内组胺，(2)辨别颗粒变化 关于酸碱度和组胺的流动性 在胞吐过程中颗粒的挤出，以及(3)充分 描述颗粒剂对组胺的结合作用 亲和力常数和结合位点。这些目标将是 通过使用非侵入性的1H核磁共振完成 核磁共振波谱检测完整肥大细胞中的组胺 组胺-颗粒和组胺-糖胺多糖模型 系统。组胺在完整细胞和肥大细胞中的流动性 它们在刺激后被阻止，并在颗粒中 将由组胺质子的松弛时间确定。 颗粒剂与组胺结合的亲和力常数 糖胺多聚糖将通过化学位移和 强度测量。颗粒内的pH值将通过以下方式确定 使用添加的咪唑作为核磁共振pH指示剂，而小的， 中性、颗粒可渗透的分子，如甲醇，将被 用作水量的记录器。预计这些 研究将有助于加深对肥大细胞的理解 故意扰乱环境的行为 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.