Eye opening rapidly induces synaptic potentiation and refinement.
NMDA receptor (NMDAR)-mediated increases in AMPA receptor (AMPAR) currents are associated with long-term synaptic potentiation (LTP). Here, we provide evidence that similar changes occur in response to normal increases in sensory stimulation during development. Experiments discriminated between eye opening-induced and age-dependent changes in synaptic currents. At 6 hr after eye opening (AEO), a transient population of currents mediated by NR2B-rich NMDARs increase significantly, and silent synapses peak. Sustained increases in evoked and miniature AMPAR currents occur at 12 hr AEO. Significant changes in AMPAR:NMDAR evoked current ratios, contacts per axon, and inputs per cell are present at 24 hr AEO. The AMPAR current changes are those seen in vitro during NMDAR-dependent LTP. Here, they are a consequence of eye opening and are associated with a new wave of synaptic refinement. These data also suggest that new NR2B-rich NMDAR currents precede and may initiate this developmental synaptic potentiation and functional tuning.
Lu
Wei
W
Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge 02139, USA.
Constantine-Paton
Martha
M
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology*; D001369:Axons / Q000502:physiology; D004553:Electric Conductivity; D005143:Eyelids / Q000502:physiology*; D009473:Neuronal Plasticity; D017729:Presynaptic Terminals / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D013477:Superior Colliculi / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D013997:Time Factors
D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate