Endogenous activation of kainate receptors regulates glutamate release and network activity in the developing hippocampus

1. J Neurosci. 2005 May 4;25(18):4473-84.

Endogenous activation of kainate receptors regulates glutamate release and
network activity in the developing hippocampus.

Lauri SE(1), Segerstråle M, Vesikansa A, Maingret F, Mulle C, Collingridge GL,
Isaac JT, Taira T.

Author information:
(1)Neuroscience Center and Department of Biological and Environmental Sciences,
University of Helsinki, 00014 Helsinki, Finland.

Kainate receptors (KARs) are highly expressed throughout the neonatal brain, but
their function during development is unclear. Here, we show that the maturation
of the hippocampus is associated with a switch in the functional role of
presynaptic KARs. In a developmental period restricted to the first postnatal
week, endogenous L-glutamate tonically activates KARs at CA3 glutamatergic
synapses to regulate release in an action potential-independent manner. At
synapses onto pyramidal cells, KARs inhibit glutamate release via a G-protein and
PKC-dependent mechanism. In contrast, at glutamatergic terminals onto CA3
interneurons, presynaptic KARs can facilitate release in a G-protein-independent
mechanism. In both cell types, however, KAR activation strongly upregulates
inhibitory transmission. We show that, through the interplay of these novel
diverse mechanisms, KARs strongly regulate the characteristic synchronous network
activity observed in the neonatal hippocampus. By virtue of this, KARs are likely
to play a central role in the development of hippocampal synaptic circuits.

DOI: 10.1523/JNEUROSCI.4050-04.2005
PMID: 15872094 [Indexed for MEDLINE]

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