Collins F, Dawson A
J Neurosci. 1982 Aug;2(8):1005-10. doi: 10.1523/JNEUROSCI.02-08-01005.1982.
Heart cell-conditioned medium supports extensive neurite outgrowth from dissociated parasympathetic neurons of the chicken embryo ciliary ganglion. We have shown previously that neurite outgrowth in this system depends on the deposition of a substratum-conditioning factor from conditioned medium onto the polyornithine culture substratum. However, in the presence of only the substratum-bound material, neurite outgrowth is never as extensive as in whole conditioned medium. The present report demonstrates that a different and soluble component of conditioned medium is required to achieve the rates of neurite elongation normally observed in whole conditioned medium. This second component, while unable by itself to support neurite outgrowth, is able to increase the rate of neurite elongation approximately 3-fold within 30 to 60 min of its addition. This conclusion is based on direct time-lapse observations of the rate of elongation of individual neurites before and after the addition of fractions of conditioned medium previously depleted of the substratum-conditioning factor. Correlated with the effect of such fractions of conditioned medium on the rate of neurite elongation is a change in the morphology of the growth cones, which become larger and more spread. The activity of the soluble, elongation-promoting component of conditioned medium is nondialyzable and is sensitive to treatments known to affect proteins, such as repeated freeze-thawing, heating, and trypsinization. Fractions of conditioned medium which contain the elongation-promoting activity also contain all of the survival factor for parasympathetic neurons previously shown to be present in heart cell-conditioned medium. The methods described here represent a convenient new assay which we have used recently to demonstrate elongation-promoting factors with neuronal specificity in extracts of rat hippocampus.
心脏细胞条件培养基能支持鸡胚睫状神经节解离的副交感神经元长出大量神经突。我们之前已经表明，该系统中的神经突生长依赖于条件培养基中的一种基质调节因子沉积到聚鸟氨酸培养基质上。然而，仅存在基质结合物质时，神经突生长从未像在全条件培养基中那样广泛。本报告表明，条件培养基中一种不同的可溶性成分是实现全条件培养基中正常观察到的神经突伸长率所必需的。这种第二种成分虽然自身不能支持神经突生长，但在添加后30至60分钟内能够将神经突伸长率提高约3倍。这一结论基于对添加先前去除了基质调节因子的条件培养基组分前后单个神经突伸长率的直接延时观察。与这种条件培养基组分对神经突伸长率的影响相关的是生长锥形态的变化，生长锥变得更大且更伸展。条件培养基中可溶性、促进伸长成分的活性不可透析，并且对已知影响蛋白质的处理敏感，如反复冻融、加热和胰蛋白酶处理。含有促进伸长活性的条件培养基组分也含有先前已证明存在于心脏细胞条件培养基中的副交感神经元的所有存活因子。这里描述的方法代表了一种方便的新测定法，我们最近用它来证明大鼠海马提取物中具有神经元特异性的促进伸长因子。
