PT - JOURNAL ARTICLE AU - Scimemi, Annalisa AU - Tian, Hua AU - Diamond, Jeffrey S. TI - Neuronal Transporters Regulate Glutamate Clearance, NMDA Receptor Activation, and Synaptic Plasticity in the Hippocampus AID - 10.1523/JNEUROSCI.4845-09.2009 DP - 2009 Nov 18 TA - The Journal of Neuroscience PG - 14581--14595 VI - 29 IP - 46 4099 - http://www.jneurosci.org/content/29/46/14581.short 4100 - http://www.jneurosci.org/content/29/46/14581.full SO - J. Neurosci.2009 Nov 18; 29 AB - In the mammalian brain, the specificity of excitatory synaptic transmission depends on rapid diffusion of glutamate away from active synapses and the powerful uptake capacity of glutamate transporters in astrocytes. The extent to which neuronal glutamate transporters influence the lifetime of glutamate in the extracellular space remains unclear. Here we show that EAAC1, the predominant neuronal glutamate transporter at excitatory synapses in hippocampal area CA1, buffers glutamate released during synaptic events and prolongs the time course of its clearance by astrocytes. EAAC1 does not significantly alter activation of receptors in the synaptic cleft. Instead, it reduces recruitment of perisynaptic/extrasynaptic NR2B-containing NMDARs, thereby facilitating induction of long-term potentiation by short bursts of high-frequency stimulation. We describe novel roles of EAAC1 in regulating glutamate diffusion and propose that NMDARs at different subsynaptic locations can make distinct contributions to the regulation of synaptic strength.