Activation of groups I or III metabotropic glutamate receptors inhibits excitatory transmission in the rat subthalamic nucleus

Awad-Granko, H.; Conn, P. Jeffrey

doi:10.1016/s0028-3908(01)00047-8

Cited by 32 publications

(24 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our findings indicate that mGluR1 is located to subserve presynaptic modulatory effects on dopamine release, which is consistent with microdialysis findings showing that local application of group I mGluR agonists facilitates dopamine release in the rat striatum (Verma and Moghaddam, 1998;Bruton et al, 1999). Although group I mGluRs are commonly seen as postsynaptic receptors, they also mediate presynaptic autoreceptor or heteroreceptor inhibitory functions in various basal ganglia nuclei (Awad-Greko and Conn, 2001;Marino et al, 2001;Wittmann et al, 2001). The use of specific group I mGluR antagonist is essential to further characterize the potential functions of presynaptic mGluR1 in striatal dopaminergic terminals.…”

Section: Discussionsupporting

confidence: 90%

Group I Metabotropic Glutamate Receptors in the Monkey Striatum: Subsynaptic Association with Glutamatergic and Dopaminergic Afferents

2003

View full text Add to dashboard Cite

Group I metabotropic glutamate receptors (mGluRs) are involved in long-term synaptic plasticity and neuroprotection in the striatum, but the specific role(s) of mGluR1 and mGluR5 remain poorly understood. In this study, we used electron-microscopic immunocytochemistry to compare the pattern of subsynaptic and subcellular distribution of mGluR1a and mGluR5 in relation to putative glutamatergic and dopaminergic inputs to the monkey striatum. At the light-microscopic level, both group I mGluRs are expressed in the striatal neuropil. In addition, numerous perikarya of striatal output neurons are immunostained for mGluR5, but much less frequently for mGluR1a. At the electron-microscopic level, immunoreactivity for both receptor subtypes is primarily expressed postsynaptically in dendrites and spines, although presynaptic mGluR1a labeling of glutamatergic thalamostriatal boutons and, less frequently, dopaminergic and corticostriatal terminals is also seen. In contrast to mGluR1a, mGluR5 immunoreactivity is rarely encountered presynaptically. In postsynaptic elements, 40 -70% of immunoreactivity for both receptor subtypes is expressed intracellularly, whereas 30 -60% is apposed to the plasma membrane. More than 80% of the labeling apposed to the plasma membrane is extrasynaptic. The remaining 20% is located at the edges of putative glutamatergic synapses or in the active zone of symmetric synapses. In mGluR5-, but not mGluR1a-immunostained sections, ϳ70% of dopaminergic symmetric synapses are labeled perisynaptically.These data emphasize the differential pattern of subsynaptic localization of the two group I mGluRs and provide various presynaptic and postsynaptic sites whereby mGluR1 and mGluR5 could mediate different, but complementary, effects on glutamatergic and dopaminergic transmission in the primate striatum.

show abstract

Section: Discussionsupporting

confidence: 90%

Group I Metabotropic Glutamate Receptors in the Monkey Striatum: Subsynaptic Association with Glutamatergic and Dopaminergic Afferents

2003

View full text Add to dashboard Cite

show abstract

“…In agreement with a previous study (Cirone et al, 2002b), it was therefore concluded that presynaptic actions are the cause of the inhibitory profile of DHPG, which was also strongly supported by our data obtained with the paired-pulse paradigm. Similar observations have been made in the hippocampus and subthalamic nucleus, where DHPG enhanced PPF (Manzoni & Bockaert, 1995;Awad-Granko & Conn, 2001). At mossy fibre synapses, frequency-dependent accumulation of glutamate occurs (Scanziani et al, 1997), which leads to a downregulation of transmitter release.…”

Section: Presynaptic Actionssupporting

confidence: 80%

Presynaptic group I metabotropic glutamate receptors modulate synaptic transmission in the rat superior colliculus via 4‐AP sensitive K⁺ channels

White

Kylänpää

Christie

et al. 2003

British J Pharmacology

View full text Add to dashboard Cite

1 Group I metabotropic glutamate receptors (mGluRs) are thought to be important modulators of neuronal function in the superior colliculus (SC). Here, we investigated the pharmacology and signalling mechanisms underlying group I mGluR-mediated inhibition of neuronal excitability and synaptic transmission in the rat SC slice. 2 The group I agonist (RS)-3,5-dihydroxyphenylglycine (DHPG) potently depressed synaptically evoked excitatory postsynaptic potentials (EPSPs), currents (EPSCs), and action potentials in a dosedependent manner (IC 50 : 6.3 mM). This was strongly reduced by the broad-spectrum antagonist ( þ )-alpha-methyl-4-carboxyphenylglycine (MCPG, 1 mM, B95% reduction), by the mGluR1 antagonist LY367385 (100 mM, B80% reduction) but not by the mGluR5 antagonist 6-methyl-2-(phenylethynyl)-pyridine (MPEP, 1 -100 mM). 3 The putative mGluR5-specific agonist (RS)-2-chloro-5-hydroxyphenylglycine (CHPG, 500 mM) also inhibited EPSPs. Interestingly, CHPG's actions were not blocked by MPEP, but LY367385 (100 mM) reduced the effect of CHPG by 50%. 4 Inhibition induced by DHPG was independent of phospholipase C (PLC)/protein kinase C pathways, and did not require intact intracellular Ca 2 þ stores. It was not abolished but enhanced by the GABA A antagonist bicuculline (5 mM), suggesting that DHPG's action was not due to facilitated inhibition or changes in neuronal network activity. 5 The K þ channel antagonist 4-aminopyridine (4-AP, 50 -100 mM) converted the inhibitory effect of DHPG into facilitation. Paired-pulse depression was strongly reduced by DHPG, an effect that was also prevented by 4-AP. 6 Our data indicate that group I agonists regulate transmitter release, presumably via an autoreceptor in the SC. This receptor may be involved in adaptation to repetitive stimulation via a non-PLC mediated pathway.

show abstract

“…Previous work with group III mGluRs in other regions of the brain has shown a variety of response types, including presynaptic and postsynaptic modulation leading to circuit inhibition or excitation (Semyanov and Kullmann, 2000;Awad-Granko and Conn, 2001). Neurons in some regions of the brain show group III mGluR postsynaptic modulation (Martin et al, 1997;Taverna and Pennartz, 2003).…”

Section: Site Of Mglur Actionmentioning

confidence: 99%

“…Group III mGluRs have been localized immunocytochemically to presynaptic axons in some brain regions and to postsynaptic cells in other brain regions (Bradley et al, 1996(Bradley et al, , 1999Shigemoto et al, 1997). In some brain areas, group III mGluRs selectively inhibit excitatory synaptic activity (Awad-Granko et al, 2001). In other regions of the brain, activation of group III mGluRs has been reported to inhibit selectively GABAergic neurons, and this disinhibition led to an increase in circuit activity (Semyanov and Kullmann, 2000).…”

Section: Introductionmentioning

confidence: 99%

Group III Metabotropic Glutamate Receptors Maintain Tonic Inhibition of Excitatory Synaptic Input to Hypocretin/Orexin Neurons

Acuña-Goycolea¹,

Liu²,

Pol³

2004

J. Neurosci.

View full text Add to dashboard Cite

Activation of groups I or III metabotropic glutamate receptors inhibits excitatory transmission in the rat subthalamic nucleus

Cited by 32 publications

References 47 publications

Group I Metabotropic Glutamate Receptors in the Monkey Striatum: Subsynaptic Association with Glutamatergic and Dopaminergic Afferents

Group I Metabotropic Glutamate Receptors in the Monkey Striatum: Subsynaptic Association with Glutamatergic and Dopaminergic Afferents

Presynaptic group I metabotropic glutamate receptors modulate synaptic transmission in the rat superior colliculus via 4‐AP sensitive K⁺ channels

Group III Metabotropic Glutamate Receptors Maintain Tonic Inhibition of Excitatory Synaptic Input to Hypocretin/Orexin Neurons

Contact Info

Product

Resources

About

Activation of groups I or III metabotropic glutamate receptors inhibits excitatory transmission in the rat subthalamic nucleus

Cited by 32 publications

References 47 publications

Group I Metabotropic Glutamate Receptors in the Monkey Striatum: Subsynaptic Association with Glutamatergic and Dopaminergic Afferents

Group I Metabotropic Glutamate Receptors in the Monkey Striatum: Subsynaptic Association with Glutamatergic and Dopaminergic Afferents

Presynaptic group I metabotropic glutamate receptors modulate synaptic transmission in the rat superior colliculus via 4‐AP sensitive K+ channels

Group III Metabotropic Glutamate Receptors Maintain Tonic Inhibition of Excitatory Synaptic Input to Hypocretin/Orexin Neurons

Contact Info

Product

Resources

About

Presynaptic group I metabotropic glutamate receptors modulate synaptic transmission in the rat superior colliculus via 4‐AP sensitive K⁺ channels