Conroy W G, Ogden L F, Berg D K
Department of Biology, University of California, San Diego, La Jolla, CA 92093-0357, USA.
Neuropharmacology. 2000 Oct;39(13):2699-705. doi: 10.1016/s0028-3908(00)00132-5.
Nicotinic receptors containing the alpha7 gene product are among the most abundant in the nervous system. Because of their widespread distribution and high relative permeability to calcium, the receptors regulate a diverse array of cellular events. On chick ciliary neurons the receptors are concentrated on somatic spines folded into discrete mats on the cell body and are overlaid by a large presynaptic calyx. The receptors co-localize with filamentous actin and the actin-associated protein drebrin which are concentrated in the spines. We show here that embryonic ciliary ganglion neurons grown in dissociated cell culture express and concentrate the receptors in large clusters or plaques that form at interneuronal interfaces between small clumps of neurons. The receptors resist detergent extraction even after disruption of the actin cytoskeleton, suggesting the importance of additional molecular mechanisms determining receptor location. The cell adhesion molecules N-CAM and N-cadherin are concentrated at the receptor plaques and may influence plaque stability. Although ciliary neurons do not normally contact each other in vivo, they do so in culture and may mimic interactions normally occurring between calyx and soma in vivo. As a result the cultures may prove useful for identifying components shaping development of postsynaptic specializations on neurons.
含有α7基因产物的烟碱型受体是神经系统中最为丰富的受体之一。由于其广泛分布且对钙具有较高的相对通透性，这些受体调节着各种各样的细胞活动。在鸡睫状神经元上，这些受体集中在折叠成细胞体上离散垫子的体细胞棘上，并被一个大的突触前花萼覆盖。这些受体与丝状肌动蛋白和集中在棘中的肌动蛋白相关蛋白脑桥蛋白共定位。我们在此表明，在解离细胞培养中生长的胚胎睫状神经节神经元表达并将这些受体集中在大的簇或斑块中，这些簇或斑块形成于小神经元团块之间的神经元间界面处。即使在肌动蛋白细胞骨架被破坏后，这些受体仍能抵抗去污剂提取，这表明存在决定受体位置的其他分子机制的重要性。细胞粘附分子N-CAM和N-钙粘蛋白集中在受体斑块处，可能影响斑块稳定性。尽管睫状神经元在体内通常不相互接触，但它们在培养中会相互接触，并且可能模拟体内花萼和体细胞之间通常发生的相互作用。因此，这些培养物可能有助于识别塑造神经元突触后特化发育的成分。
