Abrahamson I K, Murdoch S Y, Rush R A
Centre for Neuroscience and Department of Human Physiology, School of Medicine, The Flinders University of South Australia, Bedford Park, 5042 South Australia.
Int J Dev Neurosci. 1984;2(3):229-39. doi: 10.1016/0736-5748(84)90017-0.
The expansor secundariorum is a smooth muscle of the chicken wing which receives a dense noradrenergic innervation and contains high concentrations of trophic activity for sympathetic neurons. Expansor cells were dissociated in trypsin and grown to confluency in standard nutrient medium. Medium that had been conditioned by expansor cells contained trophic activity for chick sympathetic nerves which differed from the activity which is found within the muscle prior to culture, in that it was effective on a different neuronal subpopulation. Furthermore, unlike the factor(s) found in vivo, the trophic activity of the conditioned medium was not enhanced by NGF and could be partially inhibited by mouse NGF antibodies. Both the production of total trophic activity in the conditioned medium and the activity which differed from that in the muscle extract, increased rapidly and to the same extent between 24 and 48 h culture. Greater concentrations of trophic activity were present in medium conditioned by smooth muscle cells than by skin cells. The conditioned medium was able to support more neurons from 11 and 18 day incubated embryos than a saturating dose of NGF. Neither this effect nor the additive effect of conditioned medium with expansor muscle extract could be attributed to the presence of neurite promoting factors. We conclude that the cultured muscle produces neuronotrophic activity that is similar to the activity found in denervated but not innervated muscle.
次级扩张肌是鸡翅的一种平滑肌，接受密集的去甲肾上腺素能神经支配，并且含有高浓度的对交感神经元具有营养活性的物质。扩张肌细胞用胰蛋白酶解离后，在标准营养培养基中生长至汇合。由扩张肌细胞条件化的培养基含有对鸡交感神经的营养活性，这种活性与培养前肌肉中发现的活性不同，因为它对不同的神经元亚群有效。此外，与体内发现的因子不同，条件化培养基的营养活性不会被神经生长因子（NGF）增强，并且可以被小鼠NGF抗体部分抑制。在24至48小时的培养期间，条件化培养基中总营养活性的产生以及与肌肉提取物中不同的活性都迅速增加且程度相同。平滑肌细胞条件化的培养基中存在的营养活性浓度高于皮肤细胞条件化的培养基。条件化培养基能够比饱和剂量的NGF支持更多来自11天和18天孵化胚胎的神经元。这种效应以及条件化培养基与扩张肌提取物的相加效应都不能归因于神经突促进因子的存在。我们得出结论，培养的肌肉产生的神经营养活性与在去神经但未受神经支配的肌肉中发现的活性相似。
