Characterization And Pharmacology Of Receptors For Gastr

各种胃肠道(GI)多肽的药理学和分子药理学正在研究中。年内研究的两个多肽受体家族分别是蛙皮素(Bn)相关多肽和血管活性肠肽相关多肽。BN相关多肽(GRP、NMB)主要与两种不同的受体(GRP-R、NMB-R)相互作用，在胃肠道和中枢神经系统(CNS)中发挥多种作用。这个项目的一个方面的目的是了解这些受体的药理学、分子药理学和细胞生物学。为了确定与蛙皮素受体家族不同成员的不同激动剂选择性高亲和力结合的关键氨基酸，我们使用了该家族不同受体的结构同源性分析和定点突变。在GRP受体和BRS-3受体之间，它们对蛙皮素(BN)的亲和力相差1000倍，我们发现了14个重要的氨基酸差异，并在每个受体中进行了替换。分子模拟和药理学研究表明，其中7个受体对Bn的高亲和力是重要的，并与这些受体的选择性有关，这表明这是一种识别对选择性和亲和力重要的氨基酸的有用方法。我们研究的第二个方面是开发代谢稳定的Bn或VIP受体亚型的选择性受体配体。为了实现这一点，对于没有选择性配体的人BRS-3受体，我们对非选择性配体中的各种氨基酸进行了替换，我们发现该配体与该受体具有高亲和力。一个类似的dTyr6，Apa-4Cl，Phe13，Nle14-Bn(6-14)被发现对人Brs3受体的选择性明显高于该家族的其他受体，这将有助于研究其在生理和病理过程中的作用。最后，利用我们之前的配基结构和功能研究，我们能够构建代谢稳定、对VPAC1受体具有高亲和力和选择性的28个氨基酸酸肽VIP的简化类似物。

The pharmacology and molecular pharmacology of various gastrointestinal (GI) peptides are being investigated. Two peptide receptor families investigated during the year are those for bombesin- (Bn) related peptides and for VIP-related peptides. Bn-related peptides (GRP, NMB) interact primarily with two distinct receptors (GRP-R, NMB-R) to mediate a number of effects in the GI tract and central nervous sytem (CNS). The aim of one aspect of this project is to understand the pharmacology, molecular pharmacology, and cell biology of these receptors. To identify key amino acids responsible for selective high affinity binding of various agonists for different members of the bombesin receptor family we used an analysis of the structural homologies of different receptors of this family and site-directed mutagenesis. Between the GRP receptor and BRS-3 recptor which different by >1000 in their affinity for bombesin (BN) we found 14 important amino acid differences which were then substituted in each receptor. Molecular modeling and pharmacolgy studies showed 7 of these were important for high affinity for Bn and contibuted to the selectivity of these receptors demonstrating this is a useful approach to identify amino acid important for selectivity and affinity. A second aspect of our studies is to develop selective receptor ligands for Bn or VIP receptor subtypes that could be metabolically stable. To accomplish this for the human BRS-3 receptor which has no selective ligands, we made substitutions of various amino acids in a nonselective ligand that we had discovered that interacted with with this receptor with high affinity. One analog dTyr6, Apa-4 Cl, Phe13, Nle14-Bn (6-14) was found to have a marked enhanced selectivity for the human BRS3 receptor over the other receptors of this family and should be useful to investigate its role in physiological and pathological processes. Lastly using our previous ligand structure function studies we were able to construct simplified analogs of the 28 amino acide peptide VIP that were metabolically stable and had high affinity and selectivity for VPAC1 receptors.