Extending the analysis of nicotinic receptor antagonists with the study of α6 nicotinic receptor subunit chimeras
Extending the analysis of nicotinic receptor antagonists with the study of α6 nicotinic receptor subunit chimeras
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DOI：
10.1016/j.neuropharm.2008.03.010
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发表时间：
2008-06-01
影响因子：
4.7
通讯作者：
Stokes, Clare
中科院分区：
文献类型：
--
作者：
Papke, Roger L.;Dwoskin, Linda P.;Stokes, Clare
异源表达系统增加了开发针对尼古丁乙酰胆碱受体（nAChR）亚型的选择性配体的可行性。然而，α 6亚基，在nAChRs的一个组成部分，介导的尼古丁的一些增强效果，是不容易在系统中表达，如非洲爪蟾卵母细胞。已经通过使用含有α 6配体结合结构域的嵌合亚基研究了含有α 6的受体药理学的某些方面。然而，这些嵌合体对α 6选择性通道阻断剂不敏感;因此，我们开发了具有α 3的跨膜和胞内结构域以及α 4的胞外结构域的α 6嵌合体（α 4/6）。我们研究了含α 4/6受体和其他重要nAChR亚型的药理学特性，包括α 7，α 4 β 2，α 4 β 4，α 3 β 4，α 3 β 2和α 3 β 2 β 3，以及含α 6/3和α 6/4嵌合体的受体。我们的数据表明，β 4亚基的存在或不存在是神经节阻滞剂美加明敏感性的重要因素，并且二氢-β-赤藓定对含有α 4亚基胞外结构域的亚型最有效。含有α 6/4亚基的受体对α-芋螺毒素PIA敏感，而含有相互的α 4/6嵌合体的受体不敏感。在尼古丁诱发的多巴胺释放的新型拮抗剂的实验中，α 4/6嵌合体表明，结构刚性是化合物的关键要素，可以导致对含α 6受体的非竞争性抑制的选择性。我们的数据扩展了原型nAChR拮抗剂的信息，并建立了α 4/6嵌合体作为一个有用的新工具，筛选药物作为选择性nAChR拮抗剂。(c)2008爱思唯尔有限公司保留所有权利。
Heterologous expression systems have increased the feasibility of developing selective ligands to target nicotinic acetylcholine receptor (nAChR) subtypes. However, the alpha 6 subunit, a component in nAChRs that mediates some of the reinforcing effects of nicotine, is not easily expressed in systems such as the Xenopus oocyte. Certain aspects of alpha 6-containing receptor pharmacology have been studied by using chimeric subunits containing the alpha 6 ligand-binding domain. However, these chimeras would not be sensitive to an alpha 6-selective channel blocker; therefore we developed an alpha 6 chimera (alpha 4/6) that has the transmembrane and intracellular domains of alpha 3 and the extracellular domain of alpha 4. We examined the pharmacological properties of alpha 4/6-containing receptors and other important nAChR subtypes, including alpha 7, alpha 4 beta 2, alpha 4 beta 4, alpha 3 beta 4, alpha 3 beta 2, and alpha 3 beta 2 beta 3, as well as receptors containing alpha 6/3 and alpha 6/4 chimeras. Our data show that the absence or presence of the beta 4 subunit is an important factor for sensitivity to the ganglionic blocker mecamylamine, and that dihydro-beta-erythroidine is most effective on subtypes containing the alpha 4 subunit extracellular domain. Receptors containing the alpha 6/4 subunit are sensitive to alpha-conotoxin PIA, while receptors containing the reciprocal alpha 4/6 chimera are insensitive. In experiments with novel antagonists of nicotine-evoked dopamine release, the alpha 4/6 chimera indicated that structural rigidity was a key element of compounds that could result in selectivity for noncompetitive inhibition of alpha 6 containing receptors. Our data extend the information available on prototypical nAChR antagonists, and establish the alpha 4/6 chimera as a useful new tool for screening drugs as selective nAChR antagonists. (c) 2008 Elsevier Ltd. All rights reserved.