Differential synaptic localization of two major gamma-aminobutyric acid type A receptor alpha subunits on hippocampal pyramidal cells

Proc Natl Acad Sci U S A. 1996 Oct 15;93(21):11939-44. doi: 10.1073/pnas.93.21.11939.

Abstract

Hippocampal pyramidal cells, receiving domain specific GABAergic inputs, express up to 10 different subunits of the gamma-aminobutyric acid type A (GABAA) receptor, but only 3 different subunits are needed to form a functional pentameric channel. We have tested the hypothesis that some subunits are selectively located at subsets of GABAergic synapses. The alpha 1 subunit has been found in most GABAergic synapses on all postsynaptic domains of pyramidal cells. In contrast, the alpha 2 subunit was located only in a subset of synapses on the somata and dendrites, but in most synapses on axon initial segments innervated by axo-axonic cells. The results demonstrate that molecular specialization in the composition of postsynaptic GABAA receptor subunits parallels GABAergic cell specialization in targeting synapses to a specific domain of postsynaptic cortical neurons.

MeSH terms

  • Animals
  • Axons / metabolism
  • Axons / ultrastructure
  • Dendrites / metabolism
  • Dendrites / ultrastructure
  • Hippocampus / metabolism*
  • Immune Sera
  • Macromolecular Substances
  • Microscopy, Immunoelectron
  • Pyramidal Cells / metabolism*
  • Pyramidal Cells / ultrastructure
  • Rats
  • Rats, Wistar
  • Receptors, GABA-A / analysis*
  • Receptors, GABA-A / metabolism
  • Synapses / metabolism*
  • Synapses / ultrastructure

Substances

  • Immune Sera
  • Macromolecular Substances
  • Receptors, GABA-A