Dubinsky J M, Morgan M, Fischbach G D
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110.
Dev Biol. 1988 Nov;130(1):209-19. doi: 10.1016/0012-1606(88)90427-7.
We have examined the variation in receptor density and area among neurite-associated acetylcholine receptor patches (NARPs) induced by chick ciliary ganglion neurons on nearby myotubes in vitro. Quantitative analysis of rhodamine-alpha-bungarotoxin (RBTX) NARPs revealed that about 15% of the NARPs were "outstanding" in terms of size (greater than 60 micron 2) and fluorescence intensity (greater than 100 units on a 0-255 scale). The total number of receptors at different NARPs ranged over 3 orders of magnitude. It is likely that variation in NARP size and intensity reflects regional variation in the ability of myotubes to respond to the neuronal influence because (1) no gradient in NARP size or intensity with distance from the soma was evident; (2) the intensities and areas of uninnervated receptor clusters (hot spots) were similar to those of NARPs; (3) acetylcholinesterase was present at the same proportion of hot spots and NARPs at all times examined. We found no physiological or morphological evidence that outstanding NARPs were more effective sites of transmitter release. Outstanding NARPs were restricted to the longest neurite of individual neurons, so they may signal trophic interactions of the sort that promote neurite outgrowth and survival.
我们研究了鸡睫状神经节神经元在体外诱导附近肌管形成的神经突相关乙酰胆碱受体斑块（NARP）之间受体密度和面积的变化。对罗丹明-α-银环蛇毒素（RBTX）标记的NARP进行定量分析发现，约15%的NARP在大小（大于60平方微米）和荧光强度（在0-255范围内大于100单位）方面表现“突出”。不同NARP上的受体总数相差超过3个数量级。NARP大小和强度的变化可能反映了肌管对神经元影响反应能力的区域差异，因为：（1）未观察到NARP大小或强度随距胞体距离的梯度变化；（2）未受神经支配的受体簇（热点）的强度和面积与NARP相似；（3）在所有检测时间点，热点和NARP中乙酰胆碱酯酶的比例相同。我们没有发现生理学或形态学证据表明突出的NARP是更有效的递质释放位点。突出的NARP局限于单个神经元最长的神经突，因此它们可能标志着促进神经突生长和存活的那种营养相互作用。
