Miniature Neurotransmission Stabilizes Synaptic Function via Tonic Suppression of Local Dendritic Protein Synthesis

Cell. 2006 May 19;125(4):785-99. doi: 10.1016/j.cell.2006.03.040.

Abstract

Activity deprivation in neurons induces a slow compensatory scaling up of synaptic strength, reflecting a homeostatic mechanism for stabilizing neuronal activity. Prior studies have focused on the loss of action potential (AP) driven neurotransmission in synaptic homeostasis. Here, we show that the miniature synaptic transmission that persists during AP blockade profoundly shapes the time course and mechanism of homeostatic scaling. A brief blockade of NMDA receptor (NMDAR) mediated miniature synaptic events ("minis") rapidly scales up synaptic strength, over an order of magnitude faster than with AP blockade alone. The rapid scaling induced by NMDAR mini blockade is mediated by increased synaptic expression of surface GluR1 and the transient incorporation of Ca2+-permeable AMPA receptors at synapses; both of these changes are implemented locally within dendrites and require dendritic protein synthesis. These results indicate that NMDAR signaling during miniature synaptic transmission serves to stabilize synaptic function through active suppression of dendritic protein synthesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Cells, Cultured
  • Cobalt / metabolism
  • Dendrites / metabolism*
  • Excitatory Amino Acid Agonists / metabolism
  • Excitatory Postsynaptic Potentials / physiology*
  • Hippocampus / cytology
  • Hippocampus / metabolism
  • Homeostasis
  • In Vitro Techniques
  • Nerve Tissue Proteins / biosynthesis*
  • Patch-Clamp Techniques
  • Protein Subunits / metabolism
  • Rats
  • Receptors, AMPA / metabolism
  • Receptors, N-Methyl-D-Aspartate / metabolism
  • Signal Transduction / physiology
  • Synapses / physiology*
  • Synaptic Transmission / physiology*

Substances

  • Excitatory Amino Acid Agonists
  • Nerve Tissue Proteins
  • Protein Subunits
  • Receptors, AMPA
  • Receptors, N-Methyl-D-Aspartate
  • Cobalt
  • glutamate receptor ionotropic, AMPA 2
  • glutamate receptor ionotropic, AMPA 1