Double dissociation of spike timing-dependent potentiation and depression by subunit-preferring NMDA receptor antagonists in mouse barrel cortex.
Spike timing-dependent plasticity (STDP) is a strong candidate for an N-methyl-D-aspartate (NMDA) receptor-dependent form of synaptic plasticity that could underlie the development of receptive field properties in sensory neocortices. Whilst induction of timing-dependent long-term potentiation (t-LTP) requires postsynaptic NMDA receptors, timing-dependent long-term depression (t-LTD) requires the activation of presynaptic NMDA receptors at layer 4-to-layer 2/3 synapses in barrel cortex. Here we investigated the developmental profile of t-LTD at layer 4-to-layer 2/3 synapses of mouse barrel cortex and studied their NMDA receptor subunit dependence. Timing-dependent LTD emerged in the first postnatal week, was present during the second week and disappeared in the adult, whereas t-LTP persisted in adulthood. An antagonist at GluN2C/D subunit-containing NMDA receptors blocked t-LTD but not t-LTP. Conversely, a GluN2A subunit-preferring antagonist blocked t-LTP but not t-LTD. The GluN2C/D subunit requirement for t-LTD appears to be synapse specific, as GluN2C/D antagonists did not block t-LTD at horizontal cross-columnar layer 2/3-to-layer 2/3 synapses, which was blocked by a GluN2B antagonist instead. These data demonstrate an NMDA receptor subunit-dependent double dissociation of t-LTD and t-LTP mechanisms at layer 4-to-layer 2/3 synapses, and suggest that t-LTD is mediated by distinct molecular mechanisms at different synapses on the same postsynaptic neuron.
The Neuronal Oscillations Group, Department of Physiology, Anatomy and Genetics, Oxford, OX1 3PT, UK.
Abhishek
A
Banerjee
Rhiannon M
RM
Meredith
Antonio
A
Rodríguez-Moreno
Susanna B
SB
Mierau
Yves P
YP
Auberson
Ole
O
Paulsen
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D017774:Long-Term Potentiation / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009415:Nerve Net / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D013003:Somatosensory Cortex / Q000502:physiology*
D016194:Receptors, N-Methyl-D-Aspartate