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Axo-dendritic synaptogenesis was examined in live hippocampal cell cultures using the fluorescent dyes DiO to label dendrites and FM 4-64 to label functional presynaptic boutons. As the first functional synaptic boutons appeared in these cultures, numerous filopodia (up to 10 micron long) were observed to extend transiently (mean lifetime 9.5 min) from(More)
The active zone is a specialized region of the presynaptic plasma membrane where synaptic vesicles dock and fuse. In this study, we have investigated the cellular mechanism underlying the transport and recruitment of the active zone protein Piccolo into nascent synapses. Our results show that Piccolo is transported to nascent synapses on an approximately 80(More)
Time-lapse microscopy, retrospective immunohistochemistry, and cultured hippocampal neurons were used to determine the time frame of individual glutamatergic synapse assembly and the temporal order in which specific molecules accumulate at new synaptic junctions. New presynaptic boutons capable of activity-evoked vesicle recycling were observed to form(More)
Recent studies indicate that active zones (AZs)-sites of neurotransmitter release-may be assembled from preassembled AZ precursor vesicles inserted into the presynaptic plasma membrane. Here we report that one putative AZ precursor vesicle of CNS synapses-the Piccolo-Bassoon transport vesicle (PTV)-carries a comprehensive set of AZ proteins genetically and(More)
Recent studies suggest that central nervous system synapses can persist for weeks, months, perhaps lifetimes, yet little is known as to how synapses maintain their structural and functional characteristics for so long. As a step toward a better understanding of synaptic maintenance we examined the loss, redistribution, reincorporation, and replenishment(More)
NATURE REVIEWS | NEUROSCIENCE VOLUME 5 | MAY 2004 | 385 Chemical synapses are sites of cell–cell contact that are specialized for the transmission of signals between neurons and their targets, which include muscles, glands or, most commonly, other neurons. Synaptic transmission depends on the tightly regulated secretion of neurotransmitters by the(More)
The formation of a growth cone at the tip of a severed axon is a key step in its successful regeneration. This process involves major structural and functional alterations in the formerly differentiated axonal segment. Here we examined the hypothesis that the large, localized, and transient elevation in the free intracellular calcium concentration ([Ca2+]i)(More)
Synaptic plasticity is widely believed to constitute a key mechanism for modifying functional properties of neuronal networks. This belief implicitly implies, however, that synapses, when not driven to change their characteristics by physiologically relevant stimuli, will maintain these characteristics over time. How tenacious are synapses over behaviorally(More)
SAP90/PSD-95 is thought to be a central organizer of the glutamatergic synapse postsynaptic reception apparatus. To assess its potential role during glutamatergic synapse formation, we used GFP-tagged SAP90/PSD-95, time lapse confocal microscopy, and cultured hippocampal neurons to determine its dynamic recruitment into new synaptic junctions. We report(More)
1. Axonal transection triggers a cascade of pathological processes that frequently lead to the degeneration of the injured neuron. It is generally believed that the degenerative process is triggered by an overwhelming influx of calcium through the cut end of the axon. 2. Theoretical considerations and indirect observations suggest that axotomy is followed(More)