Del Signore Arianna, Gotti Cecilia, De Stefano M Egle, Moretti Milena, Paggi Paola
Dipartimento di Biologia Cellulare e dello Sviluppo, Università La Sapienza, 0185-Roma, Italy.
Neurobiol Dis. 2002 Jun;10(1):54-66. doi: 10.1006/nbdi.2002.0495.
The nicotinic acetylcholine receptor (nAChR) subtypes were characterized in the superior cervical ganglion (SCG) of wild-type and dystrophin-lacking mdx mice. The binding of Epibatidine and alphaBungarotoxin, ligands for alpha3- and alpha7-containing receptors, respectively, revealed, for each ligand, a single class of high-affinity binding sites, with similar affinity in both wild-type and mdx mice. The Epibatidine-labeled receptors were immunoprecipitated by antibodies against the alpha3, beta2, and beta4 subunits. Immunocytochemistry showed that the percentage of alpha3-, beta2-, and beta4- but not of alpha7-immunopositive postsynaptic specializations was significantly lower in mdx than in wild-type mouse SCG. These observations suggest that the mouse SCG contains nAChRs, stabilized by dystrophin, in which the alpha3 subunit is associated with the beta2 and/or beta4 subunits. Conversely, dystrophin is not involved in the stabilization of the alpha7-containing nAChRs, as the percentage of alpha7-immunopositive synapses is similar in both wild-type and mdx mouse SCG.
在野生型和缺乏肌营养不良蛋白的mdx小鼠的颈上神经节（SCG）中对烟碱型乙酰胆碱受体（nAChR）亚型进行了表征。分别作为含α3和α7受体配体的埃皮巴蒂啶和α-银环蛇毒素的结合显示，对于每种配体，都存在一类单一的高亲和力结合位点，在野生型和mdx小鼠中具有相似的亲和力。用针对α3、β2和β4亚基的抗体对埃皮巴蒂啶标记的受体进行免疫沉淀。免疫细胞化学显示，mdx小鼠颈上神经节中α3、β2和β4免疫阳性突触后特化的百分比显著低于野生型小鼠，但α7免疫阳性突触后特化的百分比无显著差异。这些观察结果表明，小鼠颈上神经节含有由肌营养不良蛋白稳定的nAChR，其中α3亚基与β2和/或β4亚基相关联。相反，肌营养不良蛋白不参与含α7的nAChR的稳定，因为野生型和mdx小鼠颈上神经节中α7免疫阳性突触的百分比相似。
