Lachmund A, Gehrke D, Krieglstein K, Unsicker K
Department of Anatomy and Cell Biology, University of Heidelberg, Germany.
Neuroscience. 1994 Sep;62(2):361-70. doi: 10.1016/0306-4522(94)90371-9.
Chromaffin cells of the adrenal medulla were used to study the release of neurotrophic factors operationally defined by their capacity to promote the in vitro survival of embryonic neurons from the peripheral and central nervous system. Chromaffin cells are closely related to sympathetic neurons in terms of their transmitters and specific proteins and, like sympathetic neurons, receive preganglionic cholinergic, aminergic and peptidergic neuronal inputs. The issue of whether chromaffin cells store and secrete neurotrophic factors is therefore pertinent to the question whether trophic mechanisms may be involved in neuronal interactions and what modes of secretion are employed to liberate neurotrophic factors from neurons. Cell culture media conditioned by purified bovine chromaffin cells supported several neuron populations in vitro. Stimulation of the chromaffin cells with the cholinergic agonist carbachol (10(-4) M) increased in parallel the output of neurotrophic factor activity (assayed on chick ciliary ganglionic neurons) as well as two components specifically located in chromaffin granules, chromogranin A and catecholamines. The release of all three components was partially blocked by the Ca2+ channel blocker verapamil (10(-5) M), suggesting co-storage and -release of neurotrophic factors, chromogranin A and catecholamines in/from chromaffin granules. Neurotrophic factor activity for ciliary ganglionic neurons accumulating in the medium of unstimulated chromaffin cells decreased with time, and so did catecholamines. In contrast, amounts of neurotrophic factors and catecholamines released by challenging cells with carbachol did not significantly decline up to 62 h. The neurotrophic factor activity tested on chick ciliary, sensory and spinal cord neurons as well as on rat hippocampal neurons was heat- and trypsin-labile and could not be blocked by polyclonal antibodies against bovine nerve growth factor and the chromogranin A, B, and C. Defined fragments of chromogranin A and pancreastatin were devoid of neurotrophic activity. Our results suggest the presence of one or several neurotrophic factors in chromaffin granules, which can be released by exocytosis and may be potentially relevant for the maintenance of neurons innervating the adrenal medulla.
肾上腺髓质的嗜铬细胞被用于研究神经营养因子的释放，这些神经营养因子是根据其促进外周和中枢神经系统胚胎神经元体外存活的能力来操作定义的。嗜铬细胞在其递质和特定蛋白质方面与交感神经元密切相关，并且与交感神经元一样，接受节前胆碱能、胺能和肽能神经元输入。因此，嗜铬细胞是否储存和分泌神经营养因子的问题与营养机制是否可能参与神经元相互作用以及采用何种分泌方式从神经元中释放神经营养因子的问题相关。由纯化的牛嗜铬细胞条件培养的细胞培养基在体外支持多种神经元群体。用胆碱能激动剂卡巴胆碱（10(-4) M）刺激嗜铬细胞，同时增加了神经营养因子活性（在鸡睫状神经节神经元上测定）的输出以及特别位于嗜铬颗粒中的两种成分，嗜铬粒蛋白A和儿茶酚胺。所有三种成分的释放都被Ca2+通道阻滞剂维拉帕米（10(-5) M）部分阻断，这表明神经营养因子、嗜铬粒蛋白A和儿茶酚胺在嗜铬颗粒中共同储存和释放。在未刺激的嗜铬细胞培养基中积累的针对睫状神经节神经元的神经营养因子活性随时间下降，儿茶酚胺也是如此。相比之下，用卡巴胆碱刺激细胞释放的神经营养因子和儿茶酚胺的量在长达62小时内没有显著下降。在鸡睫状、感觉和脊髓神经元以及大鼠海马神经元上测试的神经营养因子活性对热和胰蛋白酶敏感，并且不能被针对牛神经生长因子以及嗜铬粒蛋白A、B和C的多克隆抗体阻断。嗜铬粒蛋白A和胰淀素的特定片段没有神经营养活性。我们的结果表明嗜铬颗粒中存在一种或几种神经营养因子，它们可以通过胞吐作用释放，并且可能与支配肾上腺髓质的神经元的维持潜在相关。
