Anesthesia And Airways

描述（由申请人提供）：麻醉剂对气道平滑肌（ASM）的复杂作用既可能有益（例如，缓解哮喘患者的支气管痉挛），也可能有害（例如，干扰匹配肺通气和灌注的正常机制）。这项研究计划的总体目标是继续探索麻醉剂如何影响气道。一些麻醉剂部分地通过降低对于给定浓度的胞质钙产生的力来松弛ASM（即，降低钙敏感性），一种新的麻醉作用机制。该提案将通过追求两个特定目标，重点关注导致这种效应的机制，这种效应在临床相关麻醉剂浓度下具有重要意义。我们已经发现，一些（但不是全部）麻醉剂通过抑制GTP结合蛋白（G蛋白）的受体激活来降低ASM刺激期间的钙敏感性。目的A将通过首先确定调节猪气道钙敏感性的特异性受体-G蛋白途径，使用诸如来自均质化平滑肌和透化平滑肌制备物的膜制备物中的免疫沉淀的技术来探索负责该作用的机制。这些途径的麻醉作用的网站，初步数据表明是特定的麻醉剂和途径，然后将确定，重点是G蛋白及其相关受体的作用。目的B将确定影响钙敏感性的麻醉剂是否也影响纯化的G蛋白的功能，检查鸟嘌呤核苷酸结合、GT3活性和在有和没有相关受体的异源三聚体G蛋白亚基中蛋白质缔合的生物物理参数。将这些结果与AIM A中获得的结果进行比较，以确保在分离蛋白中观察到的任何效应与组织中的作用相关。由于这些G蛋白偶联受体信号通路是常见的许多类型的细胞，这些麻醉机制在ASM的调查可能会产生洞察其他器官系统的麻醉作用。此外，控制钙敏感性的途径是治疗操作的潜在靶点，对这些系统和麻醉作用的探索可能有助于新型支气管扩张剂的开发。

DESCRIPTION (provided by applicant): The complex effects of anesthetics on airway smooth muscle (ASM) have the potential for both benefit (e g , relief of bronchospasm in patients with asthma) and harm (e.g., interference with normal mechanisms matching lung ventilation and perfusion). The overall goal of this research program is to continue exploration of how anesthetics affect the airways. Some anesthetics relax ASM in part by decreasing the force produced for a given concentration of cytosolic calcium (i.e., decreasing calcium sensitivity), a novel mechanism of anesthetic action. This proposal will focus on the mechanisms responsible for this effect, which is significant at clinically relevant anesthetic concentrations, by pursuing two specific aims. We have found that some (but not all) anesthetics reduce calcium sensitivity during stimulation of ASM by inhibiting receptor activation of GTP-binding proteins (G proteins). AIM A will explore mechanisms responsible for this action by first defining the specific receptor-G protein pathways that regulate calcium sensitivity in porcine airways, using techniques such as immunoprecipitation in membrane preparations from homogenized smooth muscle and permeabilized smooth muscle preparations. The sites of anesthetic action on these pathways, which preliminary data suggest is specific both to anesthetic agent and to pathway, will then be determined, with emphasis on the role of G proteins and their associated receptors. AIM B will determine if the anesthetics which affect calcium sensitivity also affect the function of purified G proteins, examining guanine nucleotide binding, GTPase activity, and biophysical parameters of protein association in heterotrimeric G protein subunits with and without associated receptors. These results will be compared with those obtained in AIM A to ensure that any effects observed in isolated proteins are relevant to actions in tissues. Because these G protein-coupled receptor signaling pathways are common to many types of cells, investigation of these anesthetic mechanisms in ASM may yield insight into anesthetic actions in other organ systems. Also, pathways that control calcium sensitivity are a potential target for therapeutic manipulation, and exploration of these systems and anesthetic effects may facilitate the development of novel bronchodilators.