Developmental presence and disappearance of postsynaptically silent synapses on dendritic spines of rat layer 2/3 pyramidal neurons
| Autor: | Busetto, Giuseppe, Higley, M. J., Sabatini, B. L. |
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| Rok vydání: | 2008 |
| Předmět: |
Aging
Neuronal Plasticity silent synapses musculoskeletal neural and ocular physiology Dendritic Spines Pyramidal Cells Action Potentials Neural Inhibition AMPA receptors glutamate uncaging Rats Rats Sprague-Dawley nervous system Synapses Animals Symposium Section: Related Papers Nerve Net Cells Cultured |
| Zdroj: | The Journal of physiology. 586(6) |
| ISSN: | 1469-7793 |
| Popis: | Silent synapses are synapses whose activation evokes NMDA-type glutamate receptor (NMDAR) but not AMPA-type glutamate receptor (AMPAR) mediated currents. Silent synapses are prominent early in postnatal development and are thought to play a role in the activity- and sensory-dependent refinement of neuronal circuits. The mechanisms that account for their silent nature have been controversial, and both presynaptic and postsynaptic mechanisms have been proposed. Here, we use two-photon laser uncaging of glutamate to directly activate glutamate receptors and measure AMPAR- and NMDAR-dependent currents on individual dendritic spines of rat somatosensory cortical layer 2/3 pyramidal neurons. We find that dendritic spines lacking functional surface AMPARs are commonly found before postnatal day 12 (P12) but are absent in older animals. Furthermore, AMPAR-lacking spines are contacted by release-competent presynaptic terminals. After P12, the AMPAR/NMDAR current ratio at individual spines continues to increase, consistent with continued addition of AMPARs to postsynaptic terminals. Our results confirm the existence of postsynaptically silent synapses and demonstrate that the morphology of the spine is not strongly predictive of its AMPAR content. |
| Databáze: | OpenAIRE |
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