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MEMBRANE PROCESSING OF BETA ADRENORECEPTORS

β 肾上腺素受体的膜处理

基本信息

批准号：
3286754
负责人：
Stephen B Baker
金额：
$ 10.54万
依托单位：
UNIVERSITY OF FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
1985
资助国家：
美国
起止时间：
1985-05-01 至 1992-04-30
项目状态：
已结题

项目摘要

Beta-adrenergic responsiveness is dependent upon the expression of beta-adrenoreceptors. This expression will partly be dependent upon the rate of receptor synthesis, cellular processing, insertion into the plasma membrane and coupling with other components of the system and the rate of degradation. Thus any alterations in these processes may alter responsiveness. Currently, little is known about the turnover and processing of the beta- adrenoreceptor. The long-term objective of the proposed research is to characterize, with the use of irreversible receptor ligands, the relationship between the regeneration of beta- adrenoreceptors and receptor-mediated responses. Using cultured cells, the endogenous receptors are irreversibly blocked and the time course of receptor recovery is determined with respect to: antagonist binding sites (both total and cell surface), agonist high (receptor-guanine nucleotide binding protein coupling) and low affinity states, cellular localization and the ability of the receptor to mediate adenylate cyclase stimulation. The ability of various processing inhibitors and other parameters on the receptor-response recovery period will be tested. These include temperature, membrane potential, ions, ATP levels and inhibitors of protein synthesis, microtubules and glycosylation. Comparisons will be made to a rapid receptor synthesis phase in human A431 cells. After irreversible blockade in vivo, receptor recovery in atria will be determined with respect to: agonist affinity states, the ability of the receptor to mediate cyclase stimulation and atrial tension development and the beta-1 and beta-2 subtypes (several tissues). The atrial recovery studies will then be extended to conditions where it is known that receptor expression and/or responsiveness is altered. These will initially include thyroid status and denervation with 6-hydroxydopamine. Finally, it is proposed to extend some characterization studies on some novel carbostyril based beta-agonists that show either noncovalent, nondissociating or covalent binding to the receptor. Both types of compounds produce irreversible cyclase activation in vitro. The noncovalent agonists will be radiolabeled for direct agonist binding and to study receptor processign during agonist- induced internalization with the agonist attached. The alkylating irreversible agonist will be used in several receptor regeneration studies for comparison to the irreversible antagonist. The proposed studies will provide basic information on the regeneration and cellular processing of beta-adrenoreceptors and its relationship to the ability of the receptor to mediate a response. This information may point to areas where lesions could occur during disease or therapeutic interventions may be useful to alter receptor-effector coupling and receptor mediated responses.

β-肾上腺素能反应依赖于 β-肾上腺素受体。这个表达式将部分依赖于在受体合成、细胞加工、插入进入质膜并与其他成分偶联，系统和降解速率。因此，这些过程可以改变响应性。目前，了解beta的周转和处理- 肾上腺素受体拟议的长期目标研究是表征，与使用不可逆受体配体，β- 肾上腺素受体和受体介导的反应。使用培养细胞，内源性受体被不可逆地阻断，受体恢复的时间过程相对于以下各项确定：拮抗剂结合位点（总和细胞表面），激动剂高（受体-鸟嘌呤核苷酸结合蛋白偶联）和低亲和力状态、细胞定位和细胞的能力，受体介导腺苷酸环化酶刺激。的能力各种加工抑制剂和其它参数将测试受体应答恢复期。这些包括温度、膜电位、离子、ATP水平和抑制剂蛋白质合成、微管和糖基化的过程。比较将在人A431中进入快速受体合成阶段细胞在体内不可逆阻断后，心房将根据以下方面来确定：激动剂亲和力状态，受体介导环化酶刺激的能力，心房张力发展和β-1和β-2亚型（几种组织）。然后将进行心房恢复研究扩展到已知受体表达和/或响应性被改变。这些措施最初将包括甲状腺状态和6-羟基多巴胺去神经。最后，建议对某些生物的某些特性进行研究，新的基于喹诺酮的β-激动剂，非共价、非解离或共价结合受体。这两种类型的化合物产生不可逆的环化酶激活体外将对非共价激动剂进行放射性标记，用于直接测定激动剂结合和研究受体过程中激动剂- 与激动剂连接诱导内化。烷基化不可逆激动剂将用于几种受体再生与不可逆拮抗剂进行比较的研究。的拟议的研究将提供有关 β-肾上腺素受体的再生和细胞加工，它与受体介导一种反应这些信息可能指向病变可能在疾病或治疗干预期间发生，改变受体-效应物偶联和受体介导的反应。