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Subpopulations of GABA neurons in the dentate gyrus express high levels of the α 1 subunit of the GABA A receptor
Author(s) -
Esclapez Monique,
Chang Donald K.,
Houser Carolyn R.
Publication year - 1996
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/(sici)1098-1063(1996)6:3<225::aid-hipo2>3.0.co;2-m
Subject(s) - dentate gyrus , in situ hybridization , protein subunit , hippocampal formation , gabaa receptor , glutamate decarboxylase , glutamate receptor , messenger rna , neuroscience , chemistry , somatostatin , biology , microbiology and biotechnology , receptor , biochemistry , enzyme , gene
The α 1 subunit of the γ‐aminobutyric acid (GABA) A receptor is highly expressed in a subgroup of neurons in the hippocampal formation. The distribution and chemical identities of these neurons in the dentate gyrus have been studied with double‐labeling in situ hybridization and immunohistochemical methods. Double labeling for the α 1 subunit and glutamate decarboxylase 65 (GAD65) mRNAs indicated that virtually all neurons in the dentate gyrus that are heavily labeled for the α 1 subunit are GABA neurons. However, many GAD65 mRNA‐labeled neurons in the hilus do not contain high levels of the α 1 subunit mRNA and protein. Studies were thus conducted to determine if the somatostatin neurons of the hilus were part of the α 1 subunit‐labeled group. Double labeling for the α 1 subunit and pre‐prosomatostatin mRNAs demonstrated virtually no co‐localization of these mRNAs in hilar neurons. Thus, the strongly labeled α 1 mRNA‐containing neurons and the somatostatin neurons constitute two distinct populations of hilar GABA neurons. Double labeling for the α 1 subunit polypeptide and its mRNA with immunohistochemical and in situ hybridization methods demonstrated directly that neurons of the dentate gyrus that express high levels of the α 1 subunit mRNA are the same neurons that show extensive labeling for the α 1 subunit along their somal and dendritic surfaces. The high levels of α 1 subunit expression in some populations of GABA neurons could be related to prominent disinhibitory functions of these neurons. © 1996 Wiley‐Liss, Inc.