Rapid actin-based plasticity in dendritic spines.
Dendritic spines have been proposed as primary sites of synaptic plasticity in the brain. Consistent with this hypothesis, spines contain high concentrations of actin, suggesting that they might be motile. To investigate this possibility, we made video recordings from hippocampal neurons expressing actin tagged with green fluorescent protein (GFP-actin). This reagent incorporates into actin-containing structures and allows the visualization of actin dynamics in living neurons. In mature neurons, recordings of GFP fluorescence revealed large actin-dependent changes in dendritic spine shape, similar to those inferred from previous studies using fixed tissues. Visible changes occurred within seconds, suggesting that anatomical plasticity at synapses can be extremely rapid. As well as providing a molecular basis for structural plasticity, the presence of motile actin in dendritic spines implicates the postsynaptic element as a primary site of this phenomenon.
Fischer
M
M
Friedrich Miescher Institute, Basel, Switzerland.
Kaech
S
S
Knutti
D
D
Matus
A
A
D000199:Actins / Q000502:physiology*; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002460:Cell Line; D048429:Cell Size / Q000502:physiology; D015638:Cytochalasin D / Q000494:pharmacology; D003712:Dendrites / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology*; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D049452:Green Fluorescent Proteins; D006624:Hippocampus / Q000166:cytology*; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D018715:Microscopy, Video; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000737:chemistry / Q000166:cytology / Q000648:ultrastructure; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D013569:Synapses / Q000737:chemistry / Q000502:physiology; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D013844:Thiazoles; D053778:Thiazolidines; D049452:Green Fluorescent Proteins; D015638:Cytochalasin D; C037068:latrunculin B