Neurochemistry of the Main Olfactory System

Ennis, Matthew; Hamilton, Katherine; Hayar, Abdallah

doi:10.1007/978-0-387-30374-1_6

Cited by 50 publications

(126 citation statements)

References 631 publications

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“…Mitral cells form dendrodendritic synapses with GABAergic granules cells in the external plexiform layer and with periglomerular cells in the GL (Ennis et al, 2007). Granule cells and periglomerular cells have been reported to express group I mGluRs (for review, see Ennis et al, 2007).…”

Section: Dhpg Failed To Increase Mipsc Frequency In Sub-gl Slicesmentioning

confidence: 99%

“…Granule cells and periglomerular cells have been reported to express group I mGluRs (for review, see Ennis et al, 2007). Therefore, the increase in IPSCs in mitral cells elicited by DHPG could arise from granule cells and/or periglomerular cells.…”

Section: Dhpg Failed To Increase Mipsc Frequency In Sub-gl Slicesmentioning

confidence: 99%

“…The most likely neuronal candidate in the GL giving rise to the IPSCs are periglomerular neurons, the vast majority of which contain GABA and form dendrodendritic synapses with mitral cells (for review, see Ennis et al, 2007). Like mitral cells, external tufted cells in the glomerulus also form reciprocal dendrodendritic synapses with periglomerular neurons (Ennis et al, 2007). If, as hypothesized, periglomerular cells are the source of DHPGevoked mIPSCs in mitral cells, then DHPG should also increase mIPSCs in external tufted cells, and this effect should be blocked by VGCC blockers.…”

Section: Dhpg Enhanced Mipscs In External Tufted Cellsmentioning

confidence: 99%

“…Periglomerular cells also express low-threshold Ca 2ϩ spikes and L-type LVA channels that facilitate GABA release (Murphy et al, 2005). Dopaminergic periglomerular cells, most of which also contain GABA (for review, see Ennis et al, 2007) also express T-type LVA Ca 2ϩ channels that activate at Ϫ65 mV and thus would be readily engaged by modest depolarizations from resting potential (Pignatelli et al, 2005). Additional studies are necessary to determine the role of Na ϩ spikes versus subthreshold currents and the contribution of specific VGCCs to DHPG-evoked GABA release from periglomerular cells.…”

Section: Origin and Presynaptic Mechanisms Of Mglur-driven Inhibitionmentioning

confidence: 99%

“…Main olfactory bulb (MOB) principal neurons and GABAergic interneurons express high levels of group I metabotropic glutamate receptors (mGluRs), suggesting that mGluRs play important roles in olfactory processing (for review, see Ennis et al, 2007). Activation of group I mGluRs depolarizes mitral cells and amplifies their responses to olfactory nerve (ON) input (Schoppa and Westbrook, 2001;Heinbockel et al, 2004;De Saint Jan and Westbrook, 2005;Ennis et al, 2006;Yuan and Knopfel, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Activation of Group I Metabotropic Glutamate Receptors on Main Olfactory Bulb Granule Cells and Periglomerular Cells Enhances Synaptic Inhibition of Mitral Cells

Dong

Hayar

Ennis³

2007

J. Neurosci.

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Granule and periglomerular cells in the main olfactory bulb express group I metabotropic glutamate receptors (mGluRs). The group I mGluR agonist 3,4-dihydroxyphenylglycine (DHPG) increases GABAergic spontaneous IPSCs (sIPSCs) in mitral cells, yet the presynaptic mechanism(s) involved and source(s) of the IPSCs are unknown. We investigated the actions of DHPG on sIPSCs and TTX-insensitive miniature IPSCs (mIPSCs) recorded in mitral and external tufted cells in rat olfactory bulb slices. DHPG, acting at mGluR1 and mGluR5, increased the rate but not amplitude of sIPSCs and mIPSCs in both cell types. The increase in mIPSCs depended on voltage-gated Ca 2ϩ channels but persisted when ionotropic glutamate receptors and sodium spikes were blocked. Focal DHPG puffs onto granule cells or bath application after glomerular layer (GL) excision failed to increase mIPSCs in mitral cells. Additionally, GL excision reduced sIPSCs in mitral cells by 50%, suggesting that periglomerular cells exert strong tonic GABAergic inhibition of mitral cells. In contrast, GL DHPG puffs readily increased mIPSCs. These findings indicate that DHPG-evoked GABA release from granule cells requires spikes, whereas in the GL, DHPG facilitates periglomerular cell GABA release via both spike-dependent and spike-independent presynaptic mechanisms. We speculate that mGluRs amplify spike-driven lateral inhibition through the mitral-to-granule cell circuit, whereas GL mGluRs may play a more important role in amplifying intraglomerular inhibition after subthreshold input.

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Section: Dhpg Failed To Increase Mipsc Frequency In Sub-gl Slicesmentioning

confidence: 99%

Section: Dhpg Failed To Increase Mipsc Frequency In Sub-gl Slicesmentioning

confidence: 99%

Section: Dhpg Enhanced Mipscs In External Tufted Cellsmentioning

confidence: 99%

Section: Origin and Presynaptic Mechanisms Of Mglur-driven Inhibitionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Activation of Group I Metabotropic Glutamate Receptors on Main Olfactory Bulb Granule Cells and Periglomerular Cells Enhances Synaptic Inhibition of Mitral Cells

Dong

Hayar

Ennis³

2007

J. Neurosci.

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Anatomy and Neurobiology of the Main and Accessory Olfactory Bulbs

Ennis

Holy

2015

Handbook of Olfaction and Gustation

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Expression and localization of the calmodulin‐binding protein neurogranin in the adult mouse olfactory bulb

Gribaudo

Bovetti

Garzotto

et al. 2009

J of Comparative Neurology

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Neurogranin (Ng) is a brain-specific postsynaptic protein involved in activity-dependent synaptic plasticity through modulation of Ca(2+)/calmodulin (CaM)-dependent signal transduction in neurons. In this study, using biochemical and immunohistochemical approaches, we demonstrate Ng expression in the adult mouse olfactory bulb (OB), the first relay station in odor information processing. We show that Ng is principally associated with the granule cell layer (GCL), which is composed of granule cell inhibitory interneurons. This cell type is continuously renewed during adult life and plays a key role in OB circuits, integrating and modulating the activity of mitral/tufted cells. Our results indicate that Ng localizes in the soma and dendrites of a defined subpopulation of mature GABAergic granule cells, enriched in the deep portion of the GCL. Ng-immunopositive cells largely coexpress the Ca(+)/CaM-dependent kinase IV (CaMKIV), a downstream protein of CaM signaling cascade, whereas no colocalization was observed between Ng and the calcium-binding protein calretinin. Finally, we demonstrate that adult neurogenesis contributes to the Ng-expressing population, with more newly generated Ng-positive cells integrated in the deep GCL. Together, these results provide a new specific neurochemical marker to identify a subpopulation of olfactory granule cells and suggest possible functional implications for Ng in OB plasticity mechanisms.

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Neurochemistry of the Main Olfactory System

Cited by 50 publications

References 631 publications

Activation of Group I Metabotropic Glutamate Receptors on Main Olfactory Bulb Granule Cells and Periglomerular Cells Enhances Synaptic Inhibition of Mitral Cells

Activation of Group I Metabotropic Glutamate Receptors on Main Olfactory Bulb Granule Cells and Periglomerular Cells Enhances Synaptic Inhibition of Mitral Cells

Anatomy and Neurobiology of the Main and Accessory Olfactory Bulbs

Expression and localization of the calmodulin‐binding protein neurogranin in the adult mouse olfactory bulb

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