Clozapine and other competitive antagonists reactivate risperidone-inactivated h5-HT7 receptors: radioligand binding and functional evidence for GPCR homodimer protomer interactions.
Clozapine and other competitive antagonists reactivate risperidone-inactivated h5-HT7 receptors: radioligand binding and functional evidence for GPCR homodimer protomer interactions.
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氯氮平和其他竞争性拮抗剂重新激活利培酮灭活的 h5-HT7 受体：放射性配体结合和 GPCR 同二聚体原体相互作用的功能证据。
DOI：
10.1007/s00213-010-2001-x
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发表时间：
2010
影响因子：
3.4
通讯作者：
Smith,Carol
中科院分区：
文献类型：
--
作者：
Teitler,Milt;Toohey,Nicole;Knight,JessicaA;Klein,MichaelT;Smith,Carol
利培酮和9-OH-利培酮可使h5-HT 7受体失活，显然是通过这些药物与受体之间形成的假不可逆复合物。虽然利培酮和9-OH-利培酮（“失活拮抗剂”）完全抑制受体，只有50%的受体与这些药物形成假不可逆复合物。目的本研究旨在更全面地确定利培酮和9-OH-利培酮的新作用机制，并确定是否可以逆转失活方法研究了非灭活药物（竞争性拮抗剂）使耐洗[3 H]利培酮结合与h5-HT 7受体解离的能力。此外，非灭活药物的能力，重新激活失活的H5-HT 7受体进行了研究，使用cAMP积累作为一个功能endpoint.ResultsThe竞争（非灭活）拮抗剂氯氮平和美舒麦角释放耐洗[3 H]利培酮结合到H5-HT 7受体。竞争性拮抗剂氯氮平、SB 269970、米安色林、赛庚啶、美舒麦角和ICI 169369以浓度依赖性方式重新激活利培酮失活的h5-HT 7受体。再活化的效力与这些药物对h5-HT 7受体的亲和力密切匹配（r2= 0.95），表明再活化拮抗剂与h5-HT 7受体的正构结合位点结合并通过其产生作用。生物发光共振能量转移分析表明，h5-HT 7受体形成homodimers.ConclusionsThe非灭活药物的能力，结合h5-HT 7 orthosteric网站和逆转的洗抗利培酮或9-OH-利培酮，也结合到h5-HT 7 orthosteric网站的影响，是h5-HT 7 homodimers之间的原异构体-原异构体相互作用的证据。这是第一次证明一个非突变的G-蛋白偶联受体同型二聚体在一个完整的细胞制剂中参与原聚体-原聚体相互作用。
RationaleThe h5-HT7receptor is subject to inactivation by risperidone and 9-OH-risperidone, apparently through a pseudo-irreversible complex formed between these drugs and the receptor. Although risperidone and 9-OH-risperidone (“inactivating antagonists”) completely inactivate the receptor, only 50% of the receptors form a pseudo-irreversible complex with these drugs.ObjectivesThis study aims to more fully determine the mechanism(s) responsible for the novel effects of risperidone and 9-OH-risperidone and to determine if the inactivation can be reversed (reactivation).MethodsThe ability of non-inactivating drugs (competitive antagonists) to dissociate wash-resistant [3H]risperidone binding from h5-HT7receptors was investigated. Also, the ability of non-inactivating drugs to reactivate inactivated h5-HT7receptors was investigated, using cAMP accumulation as a functional endpoint.ResultsThe competitive (non-inactivating) antagonists clozapine and mesulergine released the wash-resistant [3H]risperidone binding to the h5-HT7receptor. The competitive antagonists clozapine, SB269970, mianserin, cyproheptadine, mesulergine, and ICI169369 reactivated the risperidone-inactivated h5-HT7receptors in a concentration-dependent manner. The potencies for reactivation closely match the affinities of these drugs for the h5-HT7receptor (r2= 0.95), indicating that the reactivating antagonists are binding to and producing their effects through the orthosteric binding site of the h5-HT7receptor. Bioluminescence resonance energy transfer analyses indicate that the h5-HT7receptor forms homodimers.ConclusionsThe ability of the non-inactivating drugs to bind h5-HT7orthosteric sites and reverse the wash-resistant effects of risperidone or 9-OH-risperidone, also bound to h5-HT7orthosteric sites, is evidence for protomer–protomer interactions between h5-HT7homodimers. This is the first demonstration of a non-mutated G-protein-coupled receptor homodimer engaging in protomer–protomer interactions in an intact cell preparation.