*Wanhua Shen, *Bei Wu, Zhijun Zhang, Ying Dou, Zhi-ren Rao, Yi-ren Chen Shumin Duan, Activity-induced rapid synaptic maturation mediated by presynaptic Cdc42 signaling. Neuron, 50,401-414. May 4, 2006. [Abstract][PDF] [PDF](*Co-author). (Note: This article was featured on this month's NEURON cover and Preview by Atasoy and Kavalali(May 4, 2006) Summary | | | Maturation of presynaptic transmitter secretion machinery is a critical step in synaptogenesis. Here we report that a brief train of presynaptic action potentials rapidly converts early nonfunctional contacts between cultured hippocampal neurons into functional synapses by enhancing presynaptic glutamate release. The enhanced release was confirmed by a marked increase in the number of depolarization-induced FM4-64 puncta in the presynaptic axon. This rapid presynaptic maturation can be abolished by treatments that interfered with presynaptic BDNF and Cdc42 signaling or actin polymerization. Activation of Cdc42 by applying BDNF or bradykinin mimicked the effect of electrical activity in promoting synaptic maturation. Furthermore, activity-induced increase in presynaptic actin polymerization, as revealed by increased concentration of actin-YFP at axon boutons, was abolished by inhibiting BDNF and Cdc42 signaling. Thus, rapid presynaptic maturation induced by neuronal activity is mediated by presynaptic activation of the Cdc42 signaling pathway. |
Volume 50 Issue 3: May 4 , 2006 Next Issue: May 18 Silent synapses are frequently found in the developing brain. Using paired patch-clamp recordings from cultured hippocampal neurons at an early development stage, Shen et al. identified nonfunctional contacts that lack both AMPA- and NMDA-mediated synaptic responses and are thus different from the conventional silent synapses containing NMDA-only responses. The authors show that presynaptic theta burst stimulation rapidly converts these contacts into functional synapses due to enhanced presynaptic glutamate release and actin polymerization induced by activation of BDNF-Cdc42 signaling at presynaptic release sites. These findings reveal a novel mechanism underlying activity-induced rapid presynaptic maturation during a critical stage of synapse formation. The context and implications of this study are discussed in a Preview by Atasoy and Kavalali. 更多信息见:http://www.bioguider.com/Article/neurosci/resdev/200605/10632.shtml
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