PT - JOURNAL ARTICLE AU - Laurent Groc AU - Bengt Gustafsson AU - Eric Hanse TI - Spontaneous Unitary Synaptic Activity in CA1 Pyramidal Neurons during Early Postnatal Development: Constant Contribution of AMPA and NMDA Receptors AID - 10.1523/JNEUROSCI.22-13-05552.2002 DP - 2002 Jul 01 TA - The Journal of Neuroscience PG - 5552--5562 VI - 22 IP - 13 4099 - http://www.jneurosci.org/content/22/13/5552.short 4100 - http://www.jneurosci.org/content/22/13/5552.full SO - J. Neurosci.2002 Jul 01; 22 AB - Maturation of the glutamatergic synapse is thought to require the incorporation of AMPA receptors at pure NMDA synapses, also called “silent” synapses. However, the relative number of silent synapses at different developmental stages, and even the concept that silent synapses lack AMPA receptors, is actively debated. In the present work, spontaneous synaptic events were used to investigate the relative contribution of synaptic AMPA and NMDA receptor-mediated transmission in CA1 pyramidal cells during the early postnatal development. Spontaneous postsynaptic currents, mediated by AMPA and NMDA receptors, were recorded from visualized CA1 pyramidal neurons over the first postnatal week. AMPA/NMDA ratio for frequency was close to one, and, importantly, it was constant over the first postnatal week. These findings suggest that the vast majority of nascent glutamatergic synapses express both functional AMPA and NMDA receptors in the neonatal hippocampus.