PRIMARY CULTURES OF DISSOCIATED SYMPATHETIC NEURONS .2. INITIAL STUDIES ON CATECHOLAMINE METABOLISM
PRIMARY CULTURES OF DISSOCIATED SYMPATHETIC NEURONS .2. INITIAL STUDIES ON CATECHOLAMINE METABOLISM
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DOI：
10.1083/jcb.59.2.346
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发表时间：
1973-01-01
影响因子：
7.8
通讯作者：
PATTERSON, PH
中科院分区：
文献类型：
--
作者：
MAINS, RE;PATTERSON, PH
本文报道了分离的初级交感神经元的低密度培养的儿茶酚胺代谢的初步研究。放射性酪氨酸被用来研究在文化中的儿茶酚胺的合成和分解。研究了儿茶酚胺合成和蓄积对外部酪氨酸浓度的依赖性，并选择接近饱和的浓度（30 µM）进行进一步研究。神经细胞中的游离酪氨酸池在1小时内与细胞外酪氨酸平衡;酪氨酸的总积累（游离酪氨酸加蛋白质、儿茶酚胺和代谢物）在孵育24小时以上呈线性。此外，生物蝶呤，酪氨酸羟化酶的辅因子，只有轻微的增强儿茶酚胺的生物合成培养的神经元。而多巴胺β-羟化酶的共底物还原型抗坏血酸则明显促进多巴胺（DA）向去甲肾上腺素（NE）的转化。苯丙氨酸，像酪氨酸，作为一个前体的一些DA和NE产生的文化，但酪氨酸总是占90%以上的儿茶酚胺产生。DA池标记迅速饱和水平的文化的年龄特征。NE样本池填充更慢，并且比DA样本池大得多。放射性NE和DA在追踪实验中的消失遵循简单的指数曲线。较老的文化表现出更快的生产和更快的营业额的儿茶酚胺比年轻的文化，这表明一个成熟的过程。
Initial studies are reported on the catecholamine metabolism of low-density cultures of dissociated primary sympathetic neurons. Radioactive tyrosine was used to study the synthesis and breakdown of catecholamines in the cultures. The dependence of catecholamine synthesis and accumulation on external tyrosine concentration was examined and a concentration which is near saturation, 30 µM, was chosen for further studies. The free tyrosine pool in the nerve cells equilibrated with extracellular tyrosine within 1 h; the total accumulation of tyrosine (free tyrosine plus protein, catecholamines, and metabolites) was linear for more than 24 h of incubation. Addition of biopterin, the cofactor of tyrosine hydroxylase, only slightly enhanced catecholamine biosynthesis by the cultured neurons. However, addition of reduced ascorbic acid, the cosubstrate for dopamine ß-hydroxylase, markedly stimulated the conversion of dopamine (DA) to norepinephrine (NE). Phenylalanine, like tyrosine, served as a precursor for some of the DA and NE produced by the cultures, but tyrosine always accounted for more than 90% of the catecholamines produced.The DA pool labeled rapidly to a saturation level characteristic of the age of the culture. The NE pool filled more slowly and was much larger than the DA pool. The disappearance of radioactive NE and DA during chase experiments followed a simple exponential curve. Older cultures showed both more rapid production and more rapid turnover of the catecholamines than did younger cultures, suggesting a process of maturation.