RT Journal Article
SR Electronic
T1 High Firing Rate of Neonatal Hippocampal Interneurons Is Caused by Attenuation of Afterhyperpolarizing Potassium Currents by Tonically Active Kainate Receptors
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 6507
OP 6514
DO 10.1523/JNEUROSCI.4856-09.2010
VO 30
IS 19
A1 Segerstråle, Mikael
A1 Juuri, Juuso
A1 Lanore, Frédéric
A1 Piepponen, Petteri
A1 Lauri, Sari E.
A1 Mulle, Christophe
A1 Taira, Tomi
YR 2010
UL http://www.jneurosci.org/content/30/19/6507.abstract
AB In the neonatal hippocampus, the activity of interneurons shapes early network bursts that are important for the establishment of neuronal connectivity. However, mechanisms controlling the firing of immature interneurons remain elusive. We now show that the spontaneous firing rate of CA3 stratum lucidum interneurons markedly decreases during early postnatal development because of changes in the properties of GluK1 (formerly known as GluR5) subunit-containing kainate receptors (KARs). In the neonate, activation of KARs by ambient glutamate exerts a tonic inhibition of the medium-duration afterhyperpolarization (mAHP) by a G-protein-dependent mechanism, permitting a high interneuronal firing rate. During development, the amplitude of the apamine-sensitive K+ currents responsible for the mAHP increases dramatically because of decoupling between KAR activation and mAHP modulation, leading to decreased interneuronal firing. The developmental shift in the KAR function and its consequences on interneuronal activity are likely to have a fundamental role in the maturation of the synchronous neuronal oscillations typical for adult hippocampal circuitry.