CALCIUM REGULATION IN SINGLE AIRWAY SMOOTH MUSCLE CELLS

单气道平滑肌细胞的钙调节

• 批准号: 6165050
• 负责人: JOHN Mark MADISON
• 金额: $ 31.63万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-04-01 至 2002-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6165050
• 关键词: animal tissue; beta adrenergic agent; beta adrenergic receptor; biological transport; bronchomotion; bronchospasm; calcium channel; calcium flux; calcium indicator; calcium transporting ATPase; muscarinic receptor; muscle cells; muscle pharmacology; potassium channel; protein tyrosine kinase; respiratory muscles; respiratory pharmacology; sarcoplasmic reticulum; smooth muscle; voltage gated channel

DESCRIPTION: (adapted from abstract) Contraction of airway smooth muscle cause airway obstruction, and relaxation of this muscle is the principal action of B-adrenergic agonists used to treat asthma. Calcium, both extracellular and that released from intracellular stores, is an important second messenger that contributes to the determination of tension in smooth muscle. However, a paradox underscores our limited understanding of how cytosolic calcium concentrations ([Ca2+])i are regulated in airway smooth muscle cells. First, studies have shown that B-adrenergic agonists and muscarinic agonists both stimulated calcium influx and caused large increases in basal [Ca2+]i, yet paradoxically, had different effects on tension. To explain this, it is hypothesized that the cytosol is not homogeneous with respect to calcium concentrations. Independent of regulating the net flux of calcium that determines tension, muscarinic and B-adrenergic agonists stimulate calcium influx pathways that are either functionally or anatomically segregated at the periphery of the cell. These segregated influx pathways maintain peripheral sarcoplasmic reticulum (SR) calcium stores but are not major determinants of tension. Progress supports this general hypothesis and, further, it appears that SR refilling may have unique features in airway smooth muscle. Since SR calcium stores are important for understanding smooth muscle responses to multiple stimulations by contractile agonists as probably occurs in asthma, th aims of continuing this study are to better understand SR refilling. The aims are: (1) in the absence of agonist, determine how the sarcoplasmic reticulum (SR) refills after being depleted of calcium; (2) determine whether protein tyrosine kinases and the cytoskeleton support SR refilling: (3) characterize S refilling during sustained muscarinic stimulation; (4) characterize SR refilling in the presence of B-adrenergic agonists. To address these aims, the principal method is radiometric imaging of [Ca2+]i in single, bovine airway smooth muscle cells loaded with the calcium dye, fura-2.

描述：（改编自抽象）气道平滑肌的收缩 导致气道阻塞和放松该肌肉是主要的 B-肾上腺素能激动剂的作用用于治疗哮喘。 钙，两者都 细胞外和从细胞内存储释放的是重要的 第二使者有助于确定平稳的张力 肌肉。 但是，悖论强调了我们对如何 胞质钙浓度（[Ca2+]）I在气道中受调节 肌肉细胞。 首先，研究表明B-肾上腺素能激动剂和 毒蕈碱激动剂既刺激钙的流入，又引起了很大的 基础[Ca2+] I的增加，但自相矛盾的是，对 紧张。 为了解释这一点，假设细胞质不是 相对于钙浓度均匀。 独立于 调节决定张力，毒蕈碱和 B-肾上腺素能激动剂刺激钙涌入途径 在功能或解剖学上分离在细胞的外围。 这些 隔离的流入途径保持外围肌质网（SR） 钙存储，但不是张力的主要决定因素。 进度支持 这个总体假设，此外，SR补充似乎具有 气道平滑肌的独特功能。 由于SR钙存储是 对于理解平滑肌肉对多种刺激的反应很重要 通过收缩激动剂，可能是哮喘中发生的，以继续 这项研究旨在更好地了解SR补充。 目的是：（1） 缺乏激动剂，确定肌浆网（SR）如何补充 在钙耗尽后； （2）确定蛋白酪氨酸是否 激酶和细胞骨架支持SR补充：（3）表征S 在持续的毒蕈碱刺激期间补充； （4）表征SR 在存在B-肾上腺素能激动剂的情况下进行补充。 为了解决这些目标， 主要方法是单个牛中[Ca2+] i的辐射成像 气道平滑肌细胞，装有钙染料Fura-2。