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Immunocytochemical localization of glutamate and γ‐aminobutyric acid in the accessory olfactory bulb of the rat
Author(s) -
Quaglino Elena,
Giustetto Maurizio,
Panzanelli Patrizia,
Cantino Dario,
Fasolo Aldo,
SassoèPognetto Marco
Publication year - 1999
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19990524)408:1<61::aid-cne5>3.0.co;2-f
Subject(s) - olfactory bulb , biology , neurotransmitter , neuroscience , vomeronasal organ , neuropil , glutamate receptor , colocalization , olfactory system , immunogold labelling , inhibitory postsynaptic potential , axon , gamma aminobutyric acid , microbiology and biotechnology , anatomy , biochemistry , central nervous system , ultrastructure , receptor
Abstract The synaptic organization of the accessory olfactory bulb (AOB) was studied in the rat with antibodies against the excitatory neurotransmitter glutamate (Glu) and the inhibitory neurotransmitter γ‐aminobutyric acid (GABA). To a large extent, the immunoreactivity patterns produced by the two antibodies were complementary. Glu‐like immunoreactivity (‐LI) was observed in the glomerular neuropil, in the mitral cells, and in large neurons located in the periglomerular region. Immunogold electron microscopy revealed particularly high levels of Glu‐LI in the axon terminals of vomeronasal neurons. GABA‐LI was present in granule and periglomerular cells and in their processes. The dendritic spines of granule cells, which were presynaptic to mitral cells, were strongly labelled by the antiserum against GABA. Labelling of serial semithin sections showed that the GABA‐positive and Glu‐positive neurons of the periglomerular region are generally distinct, and colocalization of Glu and GABA occurred only in a few cells. These results are consistent with electrophysiological studies indicating that the synaptic organization of the AOB is similar to that of the main olfactory bulb. In both systems, Glu is the neurotransmitter used by primary afferents and output neurons, whereas GABA is involved in the circuits underlying lateral and feed‐back inhibition. J. Comp. Neurol. 408:61–72, 1999. © 1999 Wiley‐Liss, Inc.