An autoradiographic survey of mouse brain nicotinic acetylcholine receptors defined by null mutants
An autoradiographic survey of mouse brain nicotinic acetylcholine receptors defined by null mutants
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DOI：
10.1016/j.bcp.2011.04.019
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发表时间：
2011-10-15
影响因子：
5.8
通讯作者：
Marks, Michael J.
中科院分区：
文献类型：
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作者：
Baddick, Christopher G.;Marks, Michael J.
在中枢神经系统中表达9种烟碱受体亚单位，表明可以组装多种烟碱乙酰胆碱受体（nAChR）。一个有用的方法来确定推定的nAChR是放射性配体结合。在本研究中，通过放射自显影法测定了[I-125] α-银环蛇毒素、[I-125] α-芋螺毒素MII、5[I-125]-3-（（2S）-氮杂环丁烷甲氧基）吡啶（A-85380）和[I-125]地棘蛙素的结合，以提供许多nAChR结合位点的数据。对于从野生型和α 2、α 4、α 6、α 7、β 2、β 4、α 5和β 3无效突变小鼠制备的样品，半定量评价每个结合位点。α 7亚基的缺失完全并选择性地消除了[I-125] α-银环蛇毒素结合。在大多数脑区，[I-125] α-芋螺毒素M11的结合通过缺失α 6或132亚基而消除，并且通过缺失α 4或133亚基而减少。通过删除β 2亚基，5[I-125]A-85380的结合被完全消除，并通过删除α 4亚基显着降低。大多数，但不是全部，α 4-非依赖性位点需要α 6亚基的表达。基因缺失对总[I-125]地棘蛙素结合的影响与对[I-125]A-85380结合的影响非常相似。[I-125]地棘蛙素还标记β 4* nAChR，这在100 nM野靛碱存在下进行的孵育中很明显。无法评估α 3基因缺失的影响，但残留位点的持续存在意味着α 3* nAChR的表达。总之，这些结果证实并扩展了先前发表的nAChR基因缺失的影响的评价，并有助于定义可通过配体结合测量的nAChR亚型。(C)2011 Elsevier Inc. All rights reserved.
Nine nicotinic receptor subunits are expressed in the central nervous system indicating that a variety of nicotinic acetylcholine receptors (nAChR) may be assembled. A useful method with which to identify putative nAChR is radioligand binding. In the current study the binding of [I-125]alpha-bungarotoxin, [I-125]alpha-conotoxinMII, 5[I-125]-3-((2S)-azetidinylmethoxy)pyridine (A-85380), and [I-125]epibatidine has been measured autoradiographically to provide data on many nAChR binding sites. Each binding site was evaluated semi-quantitatively for samples prepared from wild-type and alpha 2, alpha 4, alpha 6, alpha 7, beta 2, beta 4, alpha 5 and beta 3 null mutant mice. Deletion of the alpha 7 subunit completely and selectively eliminated [I-125]alpha- bungarotoxin binding. The binding of [I-125]alpha-conotoxinM11 was eliminated in most brain regions by deletion of either the a6 or 132 subunit and is reduced by deletion of either the a4 or 133 subunit. The binding of 5[I-125]A-85380 was completely eliminated by deletion of the beta 2 subunit and significantly reduced by deletion of the alpha 4 subunit. Most, but not all, alpha 4-independent sites require expression of the alpha 6 subunit. The effect of gene deletion on total [I-125]epibatidine binding was very similar to that on [I-125]A-85380 binding. [I-125]Epibatidine also labels beta 4* nAChR, which was readily apparent for incubations conducted in the presence of 100 nM cytisine. The effects of alpha 3 gene deletion could not be evaluated, but persistence of residual sites implies the expression of alpha 3* nAChR. Taken together these results confirm and extend previously published evaluations of the effect of nAChR gene deletion and help to define the nAChR subtypes measurable by ligand binding. (C) 2011 Elsevier Inc. All rights reserved.