Untranslated region-dependent exclusive expression of high-sensitivity subforms of α4β2 and α3β2 nicotinic acetylcholine receptors
Untranslated region-dependent exclusive expression of high-sensitivity subforms of α4β2 and α3β2 nicotinic acetylcholine receptors
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DOI：
10.1124/mol.105.020198
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发表时间：
2006-07-01
影响因子：
3.6
通讯作者：
Surowy, CS
中科院分区：
文献类型：
--
作者：
Briggs, CA;Gubbins, EJ;Surowy, CS
α4β2 烟碱乙酰胆碱受体 (nAChR) 被认为是大脑中主要的尼古丁结合位点。重组 α 4 β 2 nAChR 表现出与低 EC50 和高 EC50 成分的双相浓度反应关系。这项研究表明，非翻译区 (UTR) 可以影响 α 4 β 2 和 α 3 β 2 nAChR 的高敏感性亚型的表达。注射缺乏UTR的α4和β2RNA的卵母细胞表达乙酰胆碱的双相浓度-反应关系，高灵敏度EC50值为0.5至2.5μM（占群体的14-24%），低灵敏度EC50值为110至180μM（76-86%）。相比之下，UTR 信息仅表达高敏感性 α 4 β 2 nAChR 亚型，乙酰胆碱 EC50 值为 2.2 μM。其他研究揭示了高敏感性 α 4 β 2 亚型和低敏感性 α 4 β 2 亚型之间的药理学差异。拮抗剂二氢-β-赤霉素（IC50 为 3-6 nM）和甲基乌头碱 IC50 为 40-135 nM）在高敏感性和低敏感性 α 4 β 2 之间没有选择性，而氯茚明、美加明和 d-筒箭毒碱对 α 4 β 2 亚型的选择性分别是 100 倍、8 倍和 5 倍对乙酰胆碱敏感性低。相反，鉴定了在功效和效力方面选择性激活高敏感性α4β2亚型的激动剂。此外，其中两种激动剂被证明可以激活小鼠大脑α4β2以及非洲爪蟾卵母细胞中表达的雪貂高敏感性α4β2。通过使用含有 UTR 的 RNA，还实现了新型高灵敏度 α 3 β 2 nAChR 的独家表达。这些研究 1) 为 α 4 β 2 nAChR 的多种亚型的存在提供了进一步的证据，2) 将其扩展到 α 3 β 2 nAChR，3) 证明了 UTR 对含有 β 2 nAChR 特性的影响，4) 揭示了以亚型选择性方式与 α 4 β 2 相互作用的化合物。
alpha 4 beta 2 nicotinic acetylcholine receptors (nAChRs) are recognized as the principal nicotine binding site in brain. Recombinant alpha 4 beta 2 nAChR demonstrate biphasic concentration-response relationships with low- and high-EC50 components. This study shows that untranslated regions (UTR) can influence expression of high-sensitivity subforms of alpha 4 beta 2 and alpha 3 beta 2 nAChR. Oocytes injected with alpha 4 and beta 2 RNA lacking UTR expressed biphasic concentration-response relationships for acetylcholine with high-sensitivity EC50 values of 0.5 to 2.5 mu M (14-24% of the population) and low- sensitivity EC50 values of 110 to 180 mu M (76-86%). In contrast, message with UTR expressed exclusively the high-sensitivity alpha 4 beta 2 nAChR subform with an acetylcholine EC50 value of 2.2 mu M. Additional studies revealed pharmacological differences between high- and low-sensitivity alpha 4 beta 2 subforms. Whereas the antagonists dihydro-beta-erythroidine (IC50 of 3-6 nM) and methyllycaconitine IC50 of 40-135 nM) were not selective between high- and low-sensitivity alpha 4 beta 2, chlorisondamine, mecamylamine, and d-tubocurarine were, respectively, 100-, 8-, and 5-fold selective for the alpha 4 beta 2 subform with low sensitivity to acetylcholine. Conversely, agonists that selectively activated the high- sensitivity alpha 4 beta 2 subform with respect to efficacy as well as potency were identified. Furthermore, two of these agonists were shown to activate mouse brain alpha 4 beta 2 as well as the ferret high- sensitivity alpha 4 beta 2 expressed in Xenopus laevis oocytes. With the use of UTR-containing RNA, exclusive expression of a novel high-sensitivity alpha 3 beta 2 nAChR was also achieved. These studies 1) provide further evidence for the existence of multiple subforms of alpha 4 beta 2 nAChR, 2) extend that to alpha 3 beta 2 nAChR, 3) demonstrate UTR influence on beta 2-containing nAChR properties, and 4) reveal compounds that interact with alpha 4 beta 2 in a subformselective manner.