Time for synaptically released glutamate to be taken up in the adult hippocampus

Range ~1 msec
Organism Rat Rattus norvegicus
Reference Diamond JS. Deriving the glutamate clearance time course from transporter currents in CA1 hippocampal astrocytes: transmitter uptake gets faster during development. J Neurosci. 2005 Mar 16 25(11):2906-16. p.2907 left column top paragraph & p.2914 right column 2nd paragraphPubMed ID15772350
Primary Source Bergles DE, Tzingounis AV, Jahr CE (2002) Comparison of coupled and uncoupled currents during glutamate uptake by GLT-1 transporters. J Neurosci 22: 10153–10162.PubMed ID12451116
Comments P.2906 right column bottom paragraph:"The consequences of these developmental changes were examined more quantitatively using two methods to extract the time course of uptake from the STC [Synaptically activated, transporter-mediated currents] waveform. The results indicate that synaptically released glutamate is taken up in the adult hippocampus with a time constant of ∼1 ms, three to eight times faster than in the juvenile hippocampus. Evoked synaptic responses in CA1 pyramidal cells indicated that the developmental increase in uptake capacity reduces NMDA [N-methyl-D-aspartate] receptor (NMDAR) activation by glutamate spillover in the adult hippocampal neuropil." p.2914 right column 2nd paragraph:"This apparent contradiction may be explained by kinetic properties of the transporters, which transport and unbind glutamate with similar probability and with a time constant of ∼1 ms (primary source). This imperfect efficiency may prove to be the rate-limiting step in clearance, at least in the adult, rendering submicrometer spatial inhomogeneities in transporter expression insignificant in determining the time course of uptake."
Entered by Uri M
ID 112049