Electric Studies of Excitation, Secretion & Contraction

描述(申请人提供)：细胞内钙信号和囊泡胞吐的调节是所有真核细胞的两个基本生理特性。仅在少数样本细胞类型中对它们进行了详细分析。我们需要对每种细胞类型进行准确的描述，以了解其对疾病和治疗的影响。该项目将研究胰腺β细胞、胰腺导管上皮、嗜铬细胞、垂体促性腺激素和交感神经元。它将使用膜片钳生物物理方法和光学钙离子记录器来量化分化的哺乳动物内分泌、神经和上皮细胞中钙的来源和汇。其中一个重点是钙缓冲和钙清除。在这些细胞中，细胞质缓冲和四个膜清除过程形成了钙瞬变，从而调节内分泌激素胰岛素、肾上腺素和促性腺激素的分泌以及胃肠道粘液的分泌。分泌调节缺陷是某些形式的糖尿病、不孕症、囊性纤维化和消化系统疾病的基础。我们需要基本的理解来启发新的治疗方法。该项目将确定胰腺导管上皮分泌囊泡池的动力学模型，包括其受钙离子、蛋白激酶和其他生理变量的调节。交感神经元、胰岛β细胞和胰管上皮细胞的钙缓冲和钙清除机制将被解剖并用定量模型描述。我们对促性腺激素内质网和嗜铬细胞线粒体内钙动态的分析将进一步深化。这些细胞器的钙缓冲和通量特性是什么？我们在这些细胞中的工作涉及到的过程，其失败会导致疾病，其调节提供了新的治疗方法。

DESCRIPTION (provided by applicant):Intracellular Ca 2+ signaling and the regulation of vesicular exocytosis are two fundamental physiological properties of all eukaryotic cells. They have been analyzed in detail in only a few exemplar cell types. We need precise descriptions in each cell type to understand the implications for disease and therapy. This project will study pancreatic beta-cells, pancreatic ductal epithelium, chromaffin cells, pituitary gonadotropes, and sympathetic neurons. It will use patch clamp biophysical methods and optical Ca 2+ reporters to quantitate sources and sinks of Ca 2+ in differentiated mammalian endocrine, nerve, and epithelial cells. One focus will be on Ca 2+ buffering and Ca 2+ clearance. In these cells, cytoplasmic buffering and four membrane clearance processes shape the Ca 2+ transient and thus regulate secretion of the endocrine hormones insulin, adrenaline, and gonadotropins and the secretion of mucus of the gastrointestinal tract. Defects in regulation of secretion underlie some forms of diabetes, infertility, cystic fibrosis, and digestive disorders. We need basic understanding to inspire new therapeutic approaches. This project will determine a kinetic model for the secretory vesicle pools of pancreatic ductal epithelium, including their regulation by Ca 2+, protein kinases, and other physiological variables. The Ca 2+ buffering and Ca 2+ clearance mechanisms of sympathetic neurons, pancreatic beta-cells, and pancreatic ductal epithelial cells will be dissected and described by a quantitative model. Our analysis of the Ca 2+ dynamics within the endoplasmic reticulum of gonadotropes and within the mitochondria of chromaffin cells will be deepened. What are the Ca 2+ buffering and flux properties of these organelles? Our work in these cells concerns processes whose failure leads to disease and whose modulation offers new therapies.