Growth cone and dendrite dynamics in zebrafish embryos: early events in synaptogenesis imaged in vivo.
We used time-lapse fluorescence microscopy to observe the growth of Mauthner cell axons and their postsynaptic targets, the primary motor neurons, in spinal cords of developing zebrafish embryos. Upon reaching successive motor neurons, the Mauthner growth cone paused briefly before continuing along its path. Varicosities formed at regular intervals and were preferentially associated with the target regions of the primary motor neurons. In addition, the postsynaptic motor neurons showed highly dynamic filopodia, which transiently interacted with both the growth cone and the axon. Both Mauthner cell and motor neurons were highly active, each showing motility sufficient to initiate synaptogenesis.
Jontes
J D
JD
Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305-5435, USA.
Buchanan
J
J
Smith
S J
SJ
D000818:Animals; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D002465:Cell Movement; D048429:Cell Size; D003712:Dendrites / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology; D005456:Fluorescent Dyes; D020439:Growth Cones / Q000378:metabolism*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009046:Motor Neurons / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D011554:Pseudopodia / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology* / Q000196:embryology; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000648:ultrastructure; D013997:Time Factors; D015027:Zebrafish / Q000196:embryology
D005456:Fluorescent Dyes