silicon and adenosine-3--5--cyclic-phosphorothioate

Use-dependent synapse remodeling is thought to provide a cellular mechanism for encoding durable memories, yet whether activity triggers an actual structural change has remained controversial. We use photoconductive stimulation to demonstrate activity-dependent morphological synaptic plasticity by video imaging of GFP-actin at individual synapses. A single tetanus transiently moves presynaptic actin toward and postsynaptic actin away from the synaptic junction. Repetitive spaced tetani induce glutamate receptor-dependent stable restructuring of synapses. Presynaptic actin redistributes and forms new puncta that label for an active synapse marker FM5-95 within 2 hr. Postsynaptic actin sprouts projections toward the new presynaptic actin puncta, resembling the axon-dendrite interaction during synaptogenesis. Our results indicate that activity-dependent presynaptic structural plasticity facilitates the formation of new active presynaptic terminals.

Topics: 6-Cyano-7-nitroquinoxaline-2,3-dione; Actins; Aniline Compounds; Animals; Calcium; Cells, Cultured; Cyclic AMP; Electric Stimulation; Enzyme Inhibitors; Excitatory Amino Acid Antagonists; Fluorescent Dyes; Genes, Reporter; Green Fluorescent Proteins; Hippocampus; Light; Luminescent Proteins; Microscopy, Video; Neuronal Plasticity; Neurons; Rats; Receptors, N-Methyl-D-Aspartate; Recombinant Fusion Proteins; Signal Transduction; Silicon; Synapses; Thionucleotides; Valine; Xanthenes