Buc-Caron M H, Nystrom P, Fischbach G D
Dev Biol. 1983 Feb;95(2):378-86. doi: 10.1016/0012-1606(83)90039-8.
We have studied the effect of saline and acid extracts of chick brain on the total number of acetylcholine (ACh) receptors and the number of receptor clusters in cultured chick muscle cells. Myotubes in 7-day cultures responded more rapidly to brain extract than did myotubes in 4-day cultures, so the older cells were used in subsequent bioassays. A large percentage of the receptor inducing activity was soluble in 2% trifluoroacetic acid (TFA), and this material appeared by Sephadex G-25 chromatography to be about 1000 daltons in size. Activity was retained on octadecasilyl silica and was further purified by reverse-phase high-pressure liquid chromatography using a TFA-acetonitrile gradient system. Material that eluted between 35 and 40% acetonitrile, termed C4018, was 500- to 1000-fold more potent than saline extract. The receptor accumulation induced by C4018 was associated with an increased rate of receptor incorporation, presumably receptor synthesis, rather than to a decrease in receptor degradation. An increase in incorporation was detected as early as 3 hr after C4018 was added to 7-day cultures and the effect was maximal after 10 hr. C4018 also promoted the aggregation of receptors that were already incorporated in the surface membrane at the time to addition. It is not yet known if aggregation of "old" receptors and increased receptor synthesis are related or if the two phenomena are mediated by the same molecule.
我们研究了鸡脑盐水提取物和酸提取物对培养的鸡肌肉细胞中乙酰胆碱（ACh）受体总数及受体簇数量的影响。7天培养的肌管对脑提取物的反应比4天培养的肌管更快，所以在后续生物测定中使用较老的细胞。很大一部分受体诱导活性可溶于2%三氟乙酸（TFA），通过Sephadex G - 25色谱分析，该物质大小约为1000道尔顿。活性保留在十八烷基硅烷硅胶上，并使用TFA - 乙腈梯度系统通过反相高压液相色谱进一步纯化。在35%至40%乙腈之间洗脱的物质，称为C4018，其效力比盐水提取物高500至1000倍。C4018诱导的受体积累与受体掺入率增加有关，推测是受体合成增加，而非受体降解减少。早在向7天培养物中添加C4018后3小时就检测到掺入增加，10小时后效果达到最大。C4018还促进了在添加时已掺入表面膜的受体聚集。尚不清楚“旧”受体的聚集与受体合成增加是否相关，或者这两种现象是否由同一分子介导。
