Feuerbach Dominik, Nozulak Joachim, Lingenhoehl Kurt, McAllister Kevin, Hoyer Daniel
Neuroscience Research, Novartis Institutes for BioMedical Research, Basel, Switzerland.
Neurosci Lett. 2007 Apr 6;416(1):61-5. doi: 10.1016/j.neulet.2007.01.045. Epub 2007 Jan 25.
This report describes the in vitro features of a novel selective nicotinic acetylcholine receptor (nAChR) alpha7 agonist, JN403, (S)-(1-Aza-bicyclo[2.2.2]oct-3-yl)-carbamic acid (S)-1-(2-fluoro-phenyl)-ethyl ester. JN403 was evaluated in a number of in vitro systems of different species, at recombinant receptors using radioligand binding, signal transduction and electrophysiological studies. When using [(125)I] alpha-bungarotoxin (alpha-BTX) as a radioligand, JN403 has high affinity for human recombinant nAChR alpha7 (pK(D)=6.7). Functionally, JN403 is a partial and potent agonist at human nAChR alpha7. The compound stimulates calcium influx in GH3 cells recombinantly expressing the human nAChR with an pEC(50) of 7.0 and an E(max) of 85% (compared to the full agonist epibatidine). In Xenopus oocytes expressing human nAChR alpha7 JN403 induces inward currents with an pEC(50) of 5.7 and an E(max) of 55%. In both recombinant systems JN403 is a partial agonist and the agonistic effects are blocked after pre-administration of methyllycaconitine (MLA, 100nM), a nAChR alpha7 antagonist. In functional calcium influx assays, JN403 displays a significantly lower potency for other subtypes of human nAChRs like alpha4beta2, alpha3beta4, alpha1beta1gammadelta as well as 5HT(3) receptors when tested functionally as an antagonist (pIC(50)<4.8) and is devoid of agonistic activity (pEC(50)<4). Similarly, JN403 shows low binding activity at a wide panel of neurotransmitter receptors. Thus, JN403 is a potent and selective nAChR alpha7 agonist and will be a useful tool for the characterization of nAChR alpha7 mediated effects both in vitro and in vivo.
本报告描述了一种新型选择性烟碱型乙酰胆碱受体（nAChR）α7激动剂JN403，即（S）-（1-氮杂双环[2.2.2]辛-3-基）-氨基甲酸（S）-1-（2-氟苯基）乙酯的体外特性。在不同物种的多种体外系统中，利用放射性配体结合、信号转导和电生理研究，对重组受体上的JN403进行了评估。当使用[（125）I]α-银环蛇毒素（α-BTX）作为放射性配体时，JN403对人重组nAChRα7具有高亲和力（pK（D）=6.7）。在功能上，JN403是一种对人nAChRα7有部分激动作用的强效激动剂。该化合物能刺激重组表达人nAChR的GH3细胞中的钙内流，pEC（50）为7.0，E（max）为85%（与完全激动剂依博加因相比）。在表达人nAChRα7的非洲爪蟾卵母细胞中，JN403诱导内向电流，pEC（50）为5.7，E（max）为55%。在这两种重组系统中，JN403都是部分激动剂，且在预先给予nAChRα7拮抗剂甲基lycaconitine（MLA，100nM）后，激动作用被阻断。在功能性钙内流试验中，当作为拮抗剂进行功能测试时，JN403对人nAChR的其他亚型如α4β2、α3β4、α1β1γδ以及5HT（3）受体的效力显著较低（pIC（50）<4.8），且无激动活性（pEC（50）<4）。同样，JN403在多种神经递质受体上显示出低结合活性。因此，JN403是一种强效且选择性的nAChRα7激动剂，将成为在体外和体内表征nAChRα7介导效应的有用工具。
