OPIATE RECEPTOR CONTROL OF POMC PEPTIDE SECRETION

描述（改编自申请人的摘要）：拟议的目标 研究的目的是阐明阿片受体控制的机制 前阿黑皮素（POMC）肽从垂体释放 中叶（IL）。 给予阿片激动剂，如 吗啡，导致大脑活动的深刻变化， 垂体POMC系统，但这些作用的机制不是 很好理解。 最近的超活性阿片激动剂实验 （D-Met 2，Pro 5）-脑啡酰胺（DMPEA）提示， 垂体神经叶（NL）可能介导DMPEA的刺激作用， 体外从IL释放POMC肽。 实验概述在 目前的提议将利用啮齿动物模型来研究 NL阿片受体在控制IL POMC肽分泌中的作用 体外 有待检验的中心假设是， NL中的受体促进化学调节剂的释放， 反过来，刺激IL POMC细胞的分泌活性。 两大 问题将得到解决。 首先，哪种阿片受体亚型（μ， δ或κ）介导DMPEA对IL POMC肽的刺激作用 体外释放？ 第二，DMPEA是否间接刺激IL细胞， 作用于邻近NL中的阿片受体以促进 POMC肽释放因子（PPRF）？ 选择性u o k受体 拮抗剂将被用来确定这些相对贡献 受体亚型对DMPEA刺激POMC肽释放的影响 已建立的固定体积体外孵育程序。 选择性受体 激动剂和拮抗剂将用于确定相对贡献 已知的NL神经化学物质对PPRF活性的影响 从DMPEA处理的NL。 如果PPRF被证明是一种不明化学品 物质，将进行初步生物化学表征， 确定推定的PPRF是蛋白质还是肽，并确定其 近似分子量。 拟议工作的结果将导致 更好地了解受体亚型介导的阿片受体激动剂 对POMC细胞的影响 这项工作产生的结果将建立一个 阿片激动剂之间相互作用的未来研究基础 和内源性神经化学系统，特别是那些在NL， 调节垂体POMC细胞的活性。

DESCRIPTION (Adapted from applicant's abstract): The goal of the proposed research is to elucidate the mechanisms subserving opiate receptor control of pro-opiomelanocortin (POMC) peptide release from the pituitary intermediate lobe (IL). Administration of opiate agonists, such as morphine, results in profound alterations in the activity of brain and pituitary POMC systems but the mechanisms underlying these effects are not well understood. Recent experiments with the super-active opiate agonist (D-Met2, Pro5)-enkephalinamide (DMPEA) suggest that opiate receptors in the pituitary neural lobe (NL) may mediate the stimulatory effects of DMPEA on POMC peptide release from the IL in vitro. Experiments outlined in the current proposal will utilize a rodent model to investigate the potential role of NL opiate receptors in controlling IL POMC peptide secretion in vitro. The central hypothesis to be tested is that activation of opiate receptors in the NL promotes the release of a chemical modulator that, in turn, stimulates the secretory activity of IL POMC cells. Two major questions will be addressed. First, which opiate receptor subtype (mu, delta, or kappa) mediates the stimulatory effect of DMPEA on IL POMC peptide release in vitro? Second, does DMPEA stimulate IL cells indirectly by acting upon opiate receptors in the adjacent NL to promote the secretion of a POMC peptide-releasing factor (PPRF)? Selective u, o, and k receptor antagonists will be used to determine the relative contribution of these receptor subtypes to DMPEA stimulation of POMC peptide release using an established, fixed-volume in-vitro incubation procedure. Selective receptor agonists and antagonists will be used to determine the relative contribution of known NL neurochemicals to PPRF activity in conditioned incubation medium from DMPEA-treated NLs. If the PPRF proves to be an unidentified chemical substance, preliminary biochemical characterization will be performed to determine if the putative PPRF is a protein or peptide and to determine its approximate molecular weight. Results from the proposed work will lead to a better understanding of the receptor subtypes mediating opiate agonist effects on POMC cells. Findings generated from this work will establish a basis for future investigations on the interactions between opiate agonists and endogenous neurochemical systems, specifically those in the NL, that modulate the activity of pituitary POMC cells.