Fukada K, Rushbrook J I, Towle M F
Department of Anatomy and Cell Biology, State University of New York, Brooklyn 11203.
Brain Res Dev Brain Res. 1991 Oct 21;62(2):203-14. doi: 10.1016/0165-3806(91)90167-h.
A glycoprotein from heart cell-conditioned medium, cholinergic neuronal differentiation factor (CDF), causes a transition from noradrenergic to cholinergic phenotype in cultured rat sympathetic neurons. Although the transition has been known to occur in a dose-dependent manner and CDF has been purified, the examination of a complete dose-response of neurons to CDF has not been possible because sufficient quantities of pure CDF have not been available. A complete dose-response curve is essential for evaluating the biological response of the neurons, for assessing the physiological role of CDF and for understanding the mechanism of action of CDF. We report here an immunoaffinity-purification procedure for CDF with a 73.1% recovery using antibodies raised against a synthetic peptide homologous with the N-terminal region of CDF. This method produced pure CDF in quantities sufficient for examination of the full dose-response range of the neurons. Our main findings are the following. The dose-responses of acetylcholine and catecholamine metabolisms to CDF are different, although the same molecule affects both transmitters. While the half-maximal concentrations for acetylcholine induction (0.20 nM) and for catecholamine suppression (0.28 nM) are similar, the response of catecholamine metabolism begins slowly and saturates at a CDF concentration (5-20 nM) considerably higher than that of acetylcholine (0.6 nM). This may indicate that CDF affects multiple processes in catecholamine metabolism.
一种来自心脏细胞条件培养基的糖蛋白，胆碱能神经元分化因子（CDF），可使培养的大鼠交感神经元从去甲肾上腺素能表型转变为胆碱能表型。尽管已知这种转变以剂量依赖方式发生且CDF已被纯化，但由于无法获得足够量的纯CDF，所以无法对神经元对CDF的完整剂量反应进行检测。完整的剂量反应曲线对于评估神经元的生物学反应、评估CDF的生理作用以及理解CDF的作用机制至关重要。我们在此报告一种CDF的免疫亲和纯化方法，使用针对与CDF N端区域同源的合成肽产生的抗体，回收率为73.1%。该方法产生的纯CDF量足以检测神经元的完整剂量反应范围。我们的主要发现如下。尽管同一分子同时影响乙酰胆碱和儿茶酚胺这两种递质，但它们对CDF的剂量反应不同。乙酰胆碱诱导的半数最大浓度（0.20 nM）和儿茶酚胺抑制的半数最大浓度（0.28 nM）相似，但儿茶酚胺代谢的反应开始缓慢，并在远高于乙酰胆碱（0.6 nM）的CDF浓度（5 - 20 nM）时达到饱和。这可能表明CDF影响儿茶酚胺代谢中的多个过程。
