Calcium transients in growth cones and axons of cultured Helisoma neurons in response to conditioning factors.
Calcium transients in growth cones and axons of cultured Helisoma neurons in response to conditioning factors.
复制标题
培养的 Helisoma 神经元的生长锥和轴突中钙瞬变对条件因素的反应。
DOI：
10.1002/neu.480270107
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Cohan,CS
中科院分区：
文献类型：
--
作者：
Williams,DK;Cohan,CS
越来越多的证据表明，细胞内钙离子水平调节生长锥的运动和轴突的延伸。本研究的目的是确定细胞内钙水平是否也影响由生长促进因子诱导的神经突延伸的起始。利用在不存在生长促进因子的情况下可以维持的轴突切断的神经元的体外制备。接种到确定培养基中的培养的Helisomabrain的远端轴突在暴露于Helisomabrain条件培养基之前不延伸神经突。这为研究与神经突延伸相关的细胞内变化提供了机会。在远端轴突处用钙敏感染料fura 2监测细胞溶质钙水平。在对照培养基中，远端轴突中的钙水平是恒定的。然而，在轴突生长锥中的胞浆钙离子的瞬时升高发生在添加条件培养基后，并与轴突延伸的起始一致。钙通道阻滞剂的应用表明，瞬态引起的跨神经元膜的钙内流。瞬变，然而，不需要神经突的延伸，虽然他们确实影响的速度和程度的神经突生长。同时细胞外补丁记录表明，钙瞬变时间相关的增加有节奏的自发电活动的细胞，这表明条件培养基影响这些神经元的离子膜特性。John Wiley & Sons，Inc.
Accumulating evidence indicates that cytosolic calcium levels regulate growth cone motility and neurite extension. The purpose of this study was to determine if intracellular calcium levels also influence the initiation of neurite extension induced by growth‐promoting factors. Anin vitropreparation of axotomized neurons that can be maintained in the absence of growth‐promoting factors was utilized. The distal axons of culturedHelisomaneurons plated into defined medium do not extend neurites until they are exposed toHelisomabrain‐conditioned medium. This provided the opportunity to study the intracellular changes associated with neurite extension. Cytosolic calcium levels were monitored with the calcium‐sensitive dye fura 2 at the distal axon. In control medium calcium levels in the distal axon were constant. However, transient elevations in cytosolic calcium in the axonal growth cone occurred after addition of conditioned medium and coincident with the initiation of neurite extension. Application of calcium channel blockers showed that the transients resulted from calcium influx across the neuronal membrane. The transients, however, were not required for neurite extension, although they did influence the rate and extent of neurite outgrowth. Simultaneous extracellular patch recordings demonstrated that the calcium transients were correlated temporally with an increase in rhythmic spontaneous electrical activity of cells, suggesting that conditioned medium influences ionic membrane properties of these neurons. © 1995 John Wiley & Sons, Inc.