Expression of distinct α subunits of GABAA receptor regulates inhibitory synaptic strength

Pavel I. Ortinski, Congyi Lu, Kentaroh Takagaki, Zhanyan Fu, Stefano Vicini

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74 Scopus citations

Abstract

Distinct α subunit subtypes in the molecular assembly of GABA A receptors are a critical determinant of the functional properties of inhibitory synapses and their modulation by a range of pharmacological agents. We investigated the contribution of these subunits to the developmental changes of inhibitory synapses in cerebellar granule neurons in primary cultures from wild-type and α1 subunit -/- mice. The decay time of miniature inhibitory postsynaptic currents (mIPSCs) halved between 6 days in vitro (DIV6) and DIV12. This was paralleled by the decrease of α2 and α3 subunits, the increase of α1 and α6 subunits expression at synapses, and changes in the action of selective α subunit modulators. A small but significant shortening of mIPSCs was observed with development in cells from -/- mice together with a decrease in the expression of α3 subunit. In contrast, the expression of α2 subunit at inhibitory synapses in -/- cells was significantly higher than in +/+ cells at DIV11-12. α5 subunit was not detected, and increased sensitivity to a selective α4/α6 subunit agonist suggests increased expression of extrasynaptic receptors in -/- mice. β2/β3 subunit expression and loreclezole sensitivity increased with development in +/+ but not in -/- cells, supporting the preferential association of the α1-with the β;2 subunit. Synaptic charge transfer strongly decreased with development but was not different between cells in the +/+ and -/- groups until DIV11-12. Our results uncover a pattern of sequential expression of α subunits underlying the changes in functional efficacy of GABAergic networks with development.

Original languageEnglish
Pages (from-to)1718-1727
Number of pages10
JournalJournal of Neurophysiology
Volume92
Issue number3
DOIs
StatePublished - Sep 2004

ASJC Scopus subject areas

  • General Neuroscience
  • Physiology

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