Adcock K H, Metzger F, Kapfhammer J P
Anatomisches Institut, University of Basel, Switzerland.
Neuroscience. 2004;127(1):137-45. doi: 10.1016/j.neuroscience.2004.04.032.
The development of the dendritic tree of a neuron is a complex process which is thought to be regulated strongly by signals from afferent fibers. In particular the synaptic activity of afferent fibers and activity-dependent signaling by neurotrophic factors are thought to affect dendritic growth. We have studied Purkinje cell dendritic arbor development in organotypic cultures under suppression of glutamate-mediated excitatory neurotransmission, achieved with multiple combinations of blockers of glutamate receptors. Despite the presence of either single receptor blockers or combinations of blockers predicted to fully suppress glutamate-mediated excitatory neurotransmission Purkinje cell dendritic arbors developed similar to those of control cultures. Furthermore, Purkinje cell dendritic arbors in organotypic cultures from brain-derived neurotrophic factor (BDNF) knockout mice or after pharmacological blockade of trk-receptors also developed in a way similar to control cultures. Our results demonstrate that during the stage of rapid dendritic arbor growth signals from afferent fibers are of minor importance for Purkinje cell dendritic development because a seemingly normal Purkinje cell dendritic tree developed in the absence of excitatory neurotransmission and BDNF signaling. Our results suggest that many aspects of Purkinje cell dendritic development can be achieved by an intrinsic growth program.
神经元树突的发育是一个复杂的过程，被认为受到传入纤维信号的强烈调控。特别是，传入纤维的突触活动以及神经营养因子介导的活性依赖信号传导被认为会影响树突生长。我们在器官型培养物中研究了浦肯野细胞树突分支的发育，通过多种谷氨酸受体阻滞剂组合抑制谷氨酸介导的兴奋性神经传递。尽管存在单一受体阻滞剂或预计能完全抑制谷氨酸介导的兴奋性神经传递的阻滞剂组合，但浦肯野细胞树突分支的发育与对照培养物相似。此外，来自脑源性神经营养因子（BDNF）基因敲除小鼠的器官型培养物中的浦肯野细胞树突分支，或在对trk受体进行药理学阻断后，其发育方式也与对照培养物相似。我们的结果表明，在树突分支快速生长阶段，传入纤维的信号对浦肯野细胞树突发育的重要性较小，因为在没有兴奋性神经传递和BDNF信号传导的情况下，似乎仍能形成正常的浦肯野细胞树突。我们的结果表明，浦肯野细胞树突发育的许多方面可以通过内在生长程序实现。
