> Merkliste Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp: E-Artikel Titel: Localization of the GABAB receptor 1a/b subunit relative to glutamatergic synapses in the dorsal cochlear nucleus of the rat Beteiligte: Luján, Rafael; Shigemoto, Ryuichi; Kulik, Akos; Juiz, José M. Erschienen: Wiley, 2004 Erschienen in: Journal of Comparative Neurology, 475 (2004) 1, Seite 36-46 Sprache: Englisch DOI: 10.1002/cne.20160 ISSN: 0021-9967; 1096-9861 Entstehung: Anmerkungen: Beschreibung: <jats:title>Abstract</jats:title><jats:p>Metabotropic γ‐aminobutyric acid receptors (GABA<jats:sub>B</jats:sub>) are involved in pre‐ and postsynaptic inhibitory effects upon auditory neurons and have been implicated in different aspects of acoustic information processing. To understand better the mechanisms by which GABA<jats:sub>B</jats:sub> receptors mediate their inhibitory effects, we used pre‐embedding immunocytochemical techniques combined with quantification of immunogold particles to reveal the precise subcellular distribution of the GABA<jats:sub>B1</jats:sub> subunit in the rat dorsal cochlear nucleus. At the light microscopic level, GABA<jats:sub>B1</jats:sub> was detected in all divisions of the cochlear complex. The most intense immunoreactivity for GABA<jats:sub>B1</jats:sub> was found in the dorsal cochlear nucleus, whereas immunoreactivity in the anteroventral and posteroventral cochlear nuclei was very low. In the dorsal cochlear nucleus, a punctate labeling was observed in the superficial (molecular and fusiform cell) layers. At the electron microscopic level, GABA<jats:sub>B1</jats:sub> was found at both post‐ and presynaptic locations. Postsynaptically, GABA<jats:sub>B1</jats:sub> was localized mainly in the dendritic spines of presumed fusiform cells. Quantitative immunogold immunocytochemistry revealed that the highest concentration of GABA<jats:sub>B1</jats:sub> in the plasma membrane was in dendritic spines, followed by dendritic shafts and somata. Thus, the most intense immunoreactivity for GABA<jats:sub>B1</jats:sub> was observed in dendritic spines with a high density of immunogold particles at extrasynaptic sites, peaking around 300 nm from glutamatergic synapses. This is in contrast to GABAergic synapses, in which GABA<jats:sub>B1</jats:sub> was only occasionally found. Presynaptically, receptor immunoreactivity was detected primarily in axospinous endings, probably from granule cells, in both the active zone and extrasynaptic sites. The localization of GABA<jats:sub>B1</jats:sub> relative to synaptic sites in the DCN suggests a role for the receptor in the regulation of dendritic excitability and excitatory inputs. J. Comp. Neurol. 475:36–46, 2004. © 2004 Wiley‐Liss, Inc.</jats:p>