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-肾上腺素能反应取决于表达 β-肾上腺素受体。此表达将部分取决于按照受体合成速率，细胞加工，插入进入质膜，并与其他成分结合系统和降解速率。因此这些过程可能会改变响应能力。目前，几乎没有知道β-的离职和处理肾上腺受体。提议的长期目标研究是通过使用不可逆的受体来表征的配体，β-的再生之间的关系肾上腺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转地阻塞，并受体恢复的时间过程是根据以下方式确定的：拮抗剂结合位点（总和细胞表面），激动剂高（受体 - 子瓜核苷酸结合蛋白偶联）和低亲和力状态，细胞定位和受体介导腺苷酸环化酶刺激。能力各种加工抑制剂和其他参数受体反应恢复期将进行测试。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。比较将在人A431的快速受体合成阶段进行细胞。在体内不可逆地封锁后，受体恢复心房将根据：激动剂亲和力状态，确定受体介导环化酶刺激的能力和心房张力的发展以及β-1和beta-2子类型（几个组织）。然后，心房恢复研究将是扩展到已知受体表达的条件和/或响应性发生了变化。这些最初将包括 6-羟基多巴胺的甲状腺状态和去神经。最后，建议扩展一些对某些的特征研究新颖的基于碳纤维的β-激动剂显示与受体的非共价，非分离或共价结合。两种化合物都会产生不可逆的循环酶激活体外。非共价激动剂将被放射标记以直接激动剂结合并研究激动剂期间的受体过程 - 诱导的内在化与附着的激动剂。烷基化不可逆的激动剂将用于几种受体再生与不可逆的拮抗剂进行比较的研究。这拟议的研究将提供有关 β-肾上腺素受体和细胞加工和细胞处理它与受体介导的能力的关系回复。此信息可能指向病变可能在疾病或治疗干预期间发生可能对改变受体效应偶联和受体介导的反应。