DEVELOPMENT OF RECEPTOR-SPECIFIC OPIOID PEPTIDE ANALOGS

描述(由申请人提供)：临床上迫切需要开发具有新的生物活性特征的阿片类镇痛剂，这种镇痛剂缺乏以下限制的副作用： 目前可以买到的鸦片类药物。该项目涉及开发阿片类激动剂和具有混合活性特征的化合物，作为药理工具和止痛剂，预计产生的副作用较少。在具体目标1中，将合成含有取代酪氨酸-1的新型苯丙氨酸类似物的阿片肽激动剂。这些化合物被设计成具有不同的阿片受体结合模式，并诱导或识别不同的受体构象。因此，这些化合物在受体信号传递或内化方面可能表现为功能选择性或偏向激动剂，并有可能作为副作用减少(如耐受性形成)的镇痛剂。其中一些多肽将以糖基化形式制备，以改善血脑屏障(BBB)的通透性。这些化合物将通过阿片受体结合试验和功能分析、受体磷酸化和内化研究、电生理研究(钙通道活性)和生物发光共振能量转移(BRET)实验进行药理学表征，以确定受体与各种信号效应物和α-arrestin的相互作用。两种炎性疼痛模型将被用来确定抗伤害感受性和止痛耐受性的发展。具体目标2的基础是观察到，联合给药和阿片类激动剂协同作用可产生强大的抗伤害作用，从而为开发混合激动剂/激动剂作为中枢作用镇痛剂提供了理论基础，产生的副作用较少。有人建议制备新的双功能化合物，其中包括与阿片肽[DMT1]DALDA相连的各种阿片激动剂，该阿片肽具有激动剂成分和血脑屏障穿透载体的双重作用。化合物将在体外进行表征，其抗伤害感受性将在急性疼痛模型中确定。他们产生止痛耐受性、身体依赖性、便秘和呼吸抑制的倾向将被检查。具体目标3涉及继续开发混合激动剂/拮抗剂，这些混合激动剂/拮抗剂具有作为中枢作用镇痛剂的潜力，但产生吗啡等激动剂的典型副作用的倾向较低。这种双功能化合物的一种设计再次使用[DMT1]Dalda作为激动剂成分和BBB穿透载体，各种中性拮抗剂、反向激动剂或部分激动剂将连接到这些载体上。在另一种设计中，激动剂/拮抗剂DIPP-NH2的糖基化类似物[？]将做好准备，努力提高其跨越BBB的能力。体外和体内药理特性将如目标2所示。

DESCRIPTION (provided by applicant): There is an urgent clinical need for the development of opioid analgesics with novel biological activity profiles that lack the limiting side effects of currently available opiates. This project concerns the development of ¿ opioid agonists and of compounds with mixed ¿/¿ activity profiles as pharmacological tools and as analgesics expected to produce fewer side effects. In Specific Aim 1, ¿ opioid peptide agonists containing novel phenylalanine analogues in place of tyrosine-1 will be synthesized. These compounds have been designed to have distinct ¿ opioid receptor binding modes and to induce or recognize a distinct receptor conformation. Therefore, these compounds may behave as functionally selective or biased ¿ agonists with regard to receptor signaling or internalization and have potential as analgesics with reduced side effects (e.g. tolerance development). Some of these peptides will be prepared in glycosylated form to improve blood-brain barrier (BBB) permeability. The compounds will be pharmacologically characterized in opioid receptor binding assays and functional assays, ¿ receptor phosphorylation and internalization studies, electrophysiological studies (Ca2+ channel activity) and bioluminescence resonance energy transfer (BRET) experiments for the identification of ¿ receptor interactions with various signaling effectors and ¿-arrestin. Two inflammatory pain models will be used to determine antinociceptive potencies and analgesic tolerance development. Specific Aim 2 is based on the observation that co-administered ¿ and ¿ opioid agonists act synergistically to produce a potent antinociceptive effect, thus providing the rationale for the development of mixed ¿ agonist/¿ agonists as centrally acting analgesics producing fewer side effects. It is proposed to prepare novel bifunctional compounds incorporating various ¿ opioid agonists linked to the opioid peptide [Dmt1]DALDA which has a dual role as ¿ agonist component and as BBB-penetrating vector. Compounds will be characterized in vitro and their antinociceptive potencies will be determined in acute pain models. Their propensities to produce analgesic tolerance, physical dependence, constipation and respiratory depression will be examined. Specific Aim 3 concerns the continued development of mixed ¿ agonist/¿ antagonists with demonstrated potential as centrally acting analgesics having low propensity to produce the typical side effects of ¿ agonists like morphine. One design of such bifunctional compounds makes again use of [Dmt1]DALDA as ¿ agonist component and BBB-penetrating vector to which various ¿ neutral antagonists, inverse agonists or partial agonists will be linked. In another design glycosylated analogues of the ¿ agonist/¿ antagonist DIPP-NH2[?] will be prepared in an effort to improve its ability to cross the BBB. The in vitro and in vivo pharmacological characterization will be as in Aim 2.