Analogs: Unique Probes for Cannabinoid Receptors

描述(申请人提供)：从SR141716A衍生的化合物的合成可能导致独特的拮抗剂、反向激动剂以及一种新的结构类别的激动剂的鉴定。SR141716A是Delta9-THC和大麻仿制药的有效拮抗剂。这些努力还可以加深我们对大麻素结构-活性关系的理解，促进我们对大麻素神经化学系统的了解，并提供与药物滥用和脑功能障碍相关的生化工具和潜在的药物制剂。拟议研究的具体目的是基于本实验室的研究结果，该研究表明可以合成具有独特特性的SR141716A类似物：对大麻素受体具有高亲和力，能够以合理的亲和力完全取代[~3H]CP55940和[~H]SR141716A，同时不能或不能取代[~H]WIN55212-2。此外，我们有证据表明，由于这种结合选择性，这些化合物具有独特的药理活性。这些结果表明，可能有必要改变目前大麻素配体-受体相互作用的范式，这可能导致研究和操纵大麻素药理学的创新方法。迄今为止产生的化合物的不同结构似乎符合三维结构-活性关系分析，这是以迭代方式进一步设计、合成和测试这类化合物的结构要求的范例。拟合成的化合物包括对吡唑核的每个取代基位置进行系统的结构修饰，还包括替代的吡唑、咪唑和吡唑并[L，5-f]菲环体系，其中取代基可能保持也可能不保持SR141716A中的原始空间关系。从SR141716A衍生的二价配体也被提出，我们认为这是首次合成二价配体来探索CB1齐聚。评估这些类似物的药理学分析将继续包括与[~H]SR141716A、[~H]CP55940和[~H]WIN55212-2在人脑和大鼠脑标本中的受体结合比较分析，以及表达CB1或CB2受体的转基因细胞系，以确定每种化合物的亲和力和选择性。将使用GTP-伽马-[35S]对选定的化合物进行公认的信号转导试验，以表征它们对抗其他拟大麻配体，特别是CP55940和WIN55212-2的效力和能力。最感兴趣的类似物也将在分离的组织(小鼠输精管和豚鼠回肠)以及在小鼠和大鼠体内进行测试，以确定具有原位和体内活性的化合物。

DESCRIPTION (provided by applicant): The synthesis of compounds derived from SR141716A, a potent antagonist of delta9-THC and cannabimimetics, may lead to the identification of unique antagonists, inverse agonists, as well as a new structural class of agonists. These efforts can also further our understanding of cannabinoid structure-activity relationships, facilitate our understanding of the cannabinoid neurochemical system and provide biochemical tools and potential medicinal agents relevant to drug abuse and to brain dysfunction. The specific aims of the proposed research are based on results of studies conducted in our laboratory showing that analogs of SR141716A could be synthesized with unique characteristics: high affinity for cannabinoid receptors, and that are able to fully displace [3H]CP55940 and [3H]SR141716A with reasonable affinity, while simultaneously much less able, or unable, to displace [3H]WIN55212-2. In addition, we have evidence to suggest that because of this binding selectivity, these compounds possess a unique profile of pharmacological activity. These results suggest that it might be necessary to change current paradigms of cannabinoid ligand-receptor interaction, and this could lead to innovative approaches to investigating, and manipulating the pharmacology of cannabinoids. The diverse structures of compounds generated to date appear amenable to three dimensional structure-activity relationship analyses, which serves as a paradigm for the further design, synthesis and testing of the structural requirements of this class of compounds in an iterative fashion. Compounds intended for synthesis comprise a systematic structural modification of each substituent position of the pyrazole nucleus and also include alternative pyrazole, imidazoles and pyrazolo [l,5-f] phenanthridine ring systems where the substituents may or may not maintain the original spacial relationships in SR141716A. Bivalent ligands derived from SR141716A are also proposed, and we believe this represents the first synthesis of bivalent ligands to probe for CB1 oligomerization. Pharmacological assays to evaluate these analogs will continue to include a comparative receptor binding assay with [3H]SR141716A, [3H]CP55940 and [3H]WIN55212-2 in human and rat brain preparations and transfected cell lines expressing CB1 or CB2 receptors to establish each compounds affinity and selectivity. An accepted signal transduction assay using GTP-gamma-[35S] will be performed on selected compounds to characterize their efficacy and ability to antagonize other cannabimimetic ligands, particularly CP55940 and WIN55212-2. Analogs of highest interest will also be tested in isolated tissues (mouse vas deferens and guinea pig ileum) and in vivo in the mouse and rat to identify compounds with in situ and in vivo activity.