Boulter J, Connolly J, Deneris E, Goldman D, Heinemann S, Patrick J
Molecular Neurobiology Laboratory, Salk Institute, San Diego, CA 92138.
Proc Natl Acad Sci U S A. 1987 Nov;84(21):7763-7. doi: 10.1073/pnas.84.21.7763.
A family of genes coding for proteins homologous to the alpha subunit of the muscle nicotinic acetylcholine receptor has been identified in the rat genome. These genes are transcribed in the central and peripheral nervous systems in areas known to contain functional nicotinic receptors. In this paper, we demonstrate that three of these genes, which we call alpha 3, alpha 4, and beta 2, encode proteins that form functional nicotinic acetylcholine receptors when expressed in Xenopus oocytes. Oocytes expressing either alpha 3 or alpha 4 protein in combination with the beta 2 protein produced a strong response to acetylcholine. Oocytes expressing only the alpha 4 protein gave a weak response to acetylcholine. These receptors are activated by acetylcholine and nicotine and are blocked by Bungarus toxin 3.1. They are not blocked by alpha-bungarotoxin, which blocks the muscle nicotinic acetylcholine receptor. Thus, the receptors formed by the alpha 3, alpha 4, and beta 2 subunits are pharmacologically similar to the ganglionic-type neuronal nicotinic acetylcholine receptor. These results indicate that the alpha 3, alpha 4, and beta 2 genes encode functional nicotinic acetylcholine receptor subunits that are expressed in the brain and peripheral nervous system.
在大鼠基因组中已鉴定出一个编码与肌肉型烟碱型乙酰胆碱受体α亚基同源蛋白质的基因家族。这些基因在已知含有功能性烟碱型受体的中枢和外周神经系统中进行转录。在本文中，我们证明其中三个基因，即我们所称的α3、α4和β2，所编码的蛋白质在非洲爪蟾卵母细胞中表达时能形成功能性烟碱型乙酰胆碱受体。与β2蛋白共同表达α3或α4蛋白的卵母细胞对乙酰胆碱产生强烈反应。仅表达α4蛋白的卵母细胞对乙酰胆碱反应较弱。这些受体可被乙酰胆碱和尼古丁激活，并被银环蛇毒素3.1阻断。它们不会被阻断肌肉型烟碱型乙酰胆碱受体的α-银环蛇毒素所阻断。因此，由α3、α4和β2亚基形成的受体在药理学上与神经节型神经元烟碱型乙酰胆碱受体相似。这些结果表明，α3、α4和β2基因编码在脑和外周神经系统中表达的功能性烟碱型乙酰胆碱受体亚基。
