Differential synaptic localization of two major gamma-aminobutyric acid type A receptor alpha subunits on hippocampal pyramidal cells.
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.
Nusser
Z
Z
Anatomical Neuropharmacology Unit, University of Oxford, United Kingdom.
Sieghart
W
W
Benke
D
D
Fritschy
J M
JM
Somogyi
P
P
D000818:Animals; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D003712:Dendrites / Q000378:metabolism / Q000648:ultrastructure; D006624:Hippocampus / Q000378:metabolism*; D007106:Immune Sera; D046911:Macromolecular Substances; D016253:Microscopy, Immunoelectron; D017966:Pyramidal Cells / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000032:analysis* / Q000378:metabolism; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure
D007106:Immune Sera; D046911:Macromolecular Substances; D011963:Receptors, GABA-A