Activation of Group III mGluRs increases the activity of 
neurons in area 17 of the cat

Activation of Group III metabotropic glutamate receptors (mGluRs) by L(+)-2-amino-4-phosphonobutyric acid (L-AP4) has different effects on in vitro slice preparations of visual cortex (Jin & Daw, 1998) as compared with in vivo recordings from somatosensory cortex (Wan & Cahusac, 1995). To investigate the role of Group III mGluRs in the cat visual cortex, in vivo recordings were made of neurons in area 17 of the visual cortex of kittens and adult cats at different ages and the effect of iontophoretic application of L-AP4 (100 mM) was examined. Application of L-AP4 resulted in an increase of the spontaneous activity and visual response of neurons to visual stimulation, the former more than the latter. The effect of L-AP4 was greatest at 3–5 weeks of age with the effect on the visual response declining more rapidly than the effect on spontaneous activity. Consistent with work in rat cortex (Jin & Daw, 1998), the effect of L-AP4 was significantly greater in upper and lower layers than in middle layers. Whole-cell in vitro recordings from slices of rat visual cortex indicated that L-AP4 (50 mM) did not increase the number of spikes elicited by increasing levels of current injections. These results confirm that L-AP4 increases activity in vivo and reasons for the discrepancy with the in vitro results are discussed.

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Effect of the Group I Metabotropic Glutamate Agonist DHPG on the Visual Cortex

Journal of Neurophysiology ◽

10.1152/jn.2001.86.4.1622 ◽

2001 ◽

Vol 86 (4) ◽

pp. 1622-1631 ◽

Cited By ~ 8

Author(s):

Xiao-Tao Jin ◽

Christopher J. Beaver ◽

Qinghua Ji ◽

Nigel W. Daw

Keyword(s):

Visual Cortex ◽

Glutamate Receptors ◽

Metabotropic Glutamate Receptors ◽

Visual Response ◽

Excitatory Effect ◽

Partial Explanation ◽

Metabotropic Glutamate ◽

Cat Visual Cortex ◽

Group I

Metabotropic glutamate receptors have a variety of effects in visual cortex that depend on the age of the animal, the layer of the cortex, and the group of the receptor. Here we describe these effects for group I receptors, using both in vivo and in vitro preparations. The metabotropic group I glutamate receptor agonist 3,5 dihydroxyphenylglycine (DHPG) potentiates the responses to N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) in slices of rat visual cortex. It also increases, initially, the visual response in the cat visual cortex. Both these effects are largest at 3–4 wk of age and decline to insignificance by 10 wk of age. Both are also largest in lower layers of cortex, which explains why the facilitatory effects found with the general metabotropic glutamate agonist 1S,3R aminocyclopentane-1,3-dicarboxylic acid (ACPD) are observed only in lower layers. Prolonged application of DHPG in the cat visual cortex, after the initial excitatory effect, produces depression. We also found that DHPG facilitates the NMDA response in fast-spiking cells, which are inhibitory, providing a partial explanation for this. Thus there are multiple effects of group I metabotropic glutamate receptors, which vary with layer and age in visual cortex.

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Effect of the Group II Metabotropic Glutamate Agonist, 2R,4R-APDC, Varies With Age, Layer, and Visual Experience in the Visual Cortex

Journal of Neurophysiology ◽

10.1152/jn.1999.82.1.86 ◽

1999 ◽

Vol 82 (1) ◽

pp. 86-93 ◽

Cited By ~ 15

Author(s):

C. J. Beaver ◽

Q.-H. Ji ◽

N. W. Daw

Keyword(s):

Visual Cortex ◽

Metabotropic Glutamate Receptors ◽

Visual Stimulation ◽

Ocular Dominance ◽

Visual Response ◽

Single Neurons ◽

Metabotropic Glutamate ◽

Layer 4 ◽

Group Ii ◽

Dark Rearing

Group II metabotropic glutamate receptors (mGluR 2/3) are distributed differentially across the layers of cat visual cortex, and this distribution varies with age. At 3–4 wk, mGluR 2/3 receptor immunoreactivity is present in all layers. By 6–8 wk of age, it is still present in extragranular layers (2, 3, 5, and 6) but has disappeared from layer 4, and dark-rearing postpones the disappearance of Group II receptors from layer 4. We examined the physiological effects of Group II activation, to see if these effects varied similarly. The responses of single neurons in cat primary visual cortex were recorded to visual stimulation, then the effect of iontophoresis of 2R,4R-4 aminopyrrolidine-2,4-decarboxylate (2R,4R-APDC), a Group II specific agonist, was observed in animals between 3 wk and adulthood. The effect of 2R,4R-APDC was generally suppressive, reducing both the visual response and spontaneous activity of single neurons. The developmental changes were in agreement with the immunohistochemical results: 2R,4R-APDC had effects on cells in all layers in animals of 3–4 wk but not in layer 4 of animals >6 wk old. Moreover, the effect of 2R,4R-APDC was reduced in the cortex of older animals (>22 wk). Dark-rearing animals to 47–54 days maintained the effects of 2R,4R-APDC in layer 4. The disappearance of Group II mGluRs from layer 4 between 3 and 6 wk of age is correlated with the segregation of ocular dominance columns in that layer, raising the possibility that mGluRs 2/3 are involved in this process.

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Activation of metabotropic glutamate receptors has different effects in different layers of cat visual cortex

Visual Neuroscience ◽

10.1017/s0952523800008786 ◽

1997 ◽

Vol 14 (1) ◽

pp. 83-88 ◽

Cited By ~ 15

Author(s):

Silvia N.M. Reid ◽

Nigel W. Daw

Keyword(s):

Visual Cortex ◽

Dicarboxylic Acid ◽

Glutamate Receptors ◽

Spontaneous Activity ◽

Primary Visual Cortex ◽

Metabotropic Glutamate Receptors ◽

Visual Response ◽

Single Neurons ◽

Metabotropic Glutamate ◽

Cat Visual Cortex

AbstractSingle neurons were recorded in cat primary visual cortex, and the effect of iontophoresis of the metabotropic glutamate agonist 1S,3R-aminocyclopentane-1.3-dicarboxylic acid (ACPD) was observed. In nearly all cases (41/43), ACPD reduced the visual response. In some cases ACPD also reduced spontaneous activity (24/43), and in other cases ACPD increased spontaneous activity (18/43). Increases were generally seen in infragranular layers (V and VI), and decreases in supragranular layers (II and III). The reduction in the visual response was also largest in supragranular layers. We conclude that activation of metabotropic glutamate receptors has both facilitatory and depressive effects in visual cortex, and the effect depends on the layer of the cell recorded.

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Metabotropic glutamate receptors switch visual response mode of lateral geniculate nucleus cells from burst to tonic

Journal of Neurophysiology ◽

10.1152/jn.1996.76.3.1800 ◽

1996 ◽

Vol 76 (3) ◽

pp. 1800-1816 ◽

Cited By ~ 62

Author(s):

D. W. Godwin ◽

J. W. Vaughan ◽

S. M. Sherman

Keyword(s):

Glutamate Receptors ◽

Lateral Geniculate Nucleus ◽

Metabotropic Glutamate Receptors ◽

Cell Activity ◽

Response Mode ◽

Visual Response ◽

Relay Cell ◽

Metabotropic Glutamate ◽

Lateral Geniculate

1. Metabotropic glutamate receptors (mGluRs) on relay cells of the lateral geniculate nucleus appear to be activated exclusively by cortical inputs. We thus sought to manipulate these receptors in an effort to gain insight into the possible role of the corticogeniculate pathway. We used in vivo recording and pharmacological techniques in cats to activate or inactivate these receptors on geniculate neurons while analyzing their response properties. 2. Iontophoretic application of the mGluR agonist 1-amino-cyclopentane-1,3-dicarboxylic acid (ACPD) to X and Y cells in the geniculate A laminae diminished or abolished burst activity characteristic of low-threshold Ca2+ spikes. This was accompanied by pronounced changes in the visual response, including a decrease in signal detectability as measured with receiver operating characteristic curves. 3. ACPD effects appear specific to mGluRs, because a specific antagonist of ionotropic glutamate receptors (iGluRs) failed to affect the ACPD-evoked responses, and antagonists of ACPD failed to affect iGluR-mediated responses. We found that 3,5-dihydroxyphenylglycine, an agonist reported to be specific for phosphatidylinositol (PI)-linked mGluRs, had effects similar to those of ACPD, implying that these effects are mediated by PI-coupled mGluRs. Furthermore, antagonists reported to be effective against PI-linked mGluRs were effective in antagonizing the ACPD-mediated effects, and substances reported to be agonists to mGluRs coupled to the adenosine 3',5'-cyclic monophosphate cascade did not affect neuronal responses on their own. These data, when added to our preliminary anatomic data, indicate that the receptor responsible for the observed effects may be mGluR1, or a functionally equivalent mGluR. 4. Activation of mGluRs produces changes in geniculate relay cell activity consistent with depolarization of these cells seen during in vitro studies. Such membrane depolarization has been shown to control the activation state of a voltage-dependent Ca2+ conductance, and this, in turn, determines whether the relay cell fires in tonic or burst mode. Our data show that application of ACPD produces a shift in response mode from burst to tonic. Because response mode is an important characteristic of the geniculate relay and because the activation state of certain mGluRs, which helps determine response mode may be controlled by corticogeniculate input, we conclude that an important function of this input is to provide a visuotopically discrete transition from burst to tonic response mode.

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Oxytocin shapes spontaneous activity patterns in the developing visual cortex by activating somatostatin interneurons

10.1101/866251 ◽

2019 ◽

Cited By ~ 1

Author(s):

Paloma P Maldonado ◽

Alvaro Nuno-Perez ◽

Jan Kirchner ◽

Elizabeth Hammock ◽

Julijana Gjorgjieva ◽

...

Keyword(s):

Visual Cortex ◽

Spontaneous Activity ◽

Sensory Processing ◽

Activity Patterns ◽

Network Activity ◽

Synaptic Connections ◽

Pairwise Correlations ◽

Early Brain Development

SummarySpontaneous network activity shapes emerging neuronal circuits during early brain development, however how neuromodulation influences this activity is not fully understood. Here, we report that the neuromodulator oxytocin powerfully shapes spontaneous activity patterns. In vivo, oxytocin strongly decreased the frequency and pairwise correlations of spontaneous activity events in visual cortex (V1), but not in somatosensory cortex (S1). This differential effect was a consequence of oxytocin only increasing inhibition in V1 and increasing both inhibition and excitation in S1. The increase in inhibition was mediated by the depolarization and increase in excitability of somatostatin+ (SST) interneurons specifically. Accordingly, silencing SST+ neurons pharmacogenetically fully blocked oxytocin’s effect on inhibition in vitro as well its effect on spontaneous activity patterns in vivo. Thus, oxytocin decreases the excitatory/inhibitory ratio and modulates specific features of V1 spontaneous activity patterns that are crucial for refining developing synaptic connections and sensory processing later in life.

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Activation of mGlu1 but not mGlu5 metabotropic glutamate receptors contributes to postischemic neuronal injury in vitro and in vivo

Pharmacology Biochemistry and Behavior ◽

10.1016/s0091-3057(02)00834-1 ◽

2002 ◽

Vol 73 (2) ◽

pp. 439-446 ◽

Cited By ~ 39

Author(s):

Elena Meli ◽

Roberta Picca ◽

Sabina Attucci ◽

Andrea Cozzi ◽

Fiamma Peruginelli ◽

...

Keyword(s):

Glutamate Receptors ◽

Metabotropic Glutamate Receptors ◽

Neuronal Injury ◽

Metabotropic Glutamate

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Group III metabotropic glutamate receptors act as hetero-receptors modulating evoked GABA release in the globus pallidus in vivo

European Journal of Pharmacology ◽

10.1016/j.ejphar.2007.10.030 ◽

2008 ◽

Vol 580 (1-2) ◽

pp. 95-99 ◽

Cited By ~ 27

Author(s):

Nicholas MacInnes ◽

Susan Duty

Keyword(s):

Glutamate Receptors ◽

Globus Pallidus ◽

Metabotropic Glutamate Receptors ◽

Gaba Release ◽

Group Iii ◽

Metabotropic Glutamate

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Metabotropic glutamate receptor signaling is required for NMDA receptor-dependent ocular dominance plasticity and LTD in visual cortex

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1512878112 ◽

2015 ◽

Vol 112 (41) ◽

pp. 12852-12857 ◽

Cited By ~ 15

Author(s):

Michael S. Sidorov ◽

Eitan S. Kaplan ◽

Emily K. Osterweil ◽

Lothar Lindemann ◽

Mark F. Bear

Keyword(s):

Visual Cortex ◽

Glutamate Receptor ◽

Metabotropic Glutamate Receptor ◽

Ocular Dominance ◽

Monocular Deprivation ◽

Excitatory Synapses ◽

Ocular Dominance Plasticity ◽

Metabotropic Glutamate

A feature of early postnatal neocortical development is a transient peak in signaling via metabotropic glutamate receptor 5 (mGluR5). In visual cortex, this change coincides with increased sensitivity of excitatory synapses to monocular deprivation (MD). However, loss of visual responsiveness after MD occurs via mechanisms revealed by the study of long-term depression (LTD) of synaptic transmission, which in layer 4 is induced by acute activation of NMDA receptors (NMDARs) rather than mGluR5. Here we report that chronic postnatal down-regulation of mGluR5 signaling produces coordinated impairments in both NMDAR-dependent LTD in vitro and ocular dominance plasticity in vivo. The data suggest that ongoing mGluR5 signaling during a critical period of postnatal development establishes the biochemical conditions that are permissive for activity-dependent sculpting of excitatory synapses via the mechanism of NMDAR-dependent LTD.

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Functional Cross-Talk between Adenosine and Metabotropic Glutamate Receptors

Current Neuropharmacology ◽

10.2174/1570159x16666180416093717 ◽

2019 ◽

Vol 17 (5) ◽

pp. 422-437 ◽

Cited By ~ 6

Author(s):

David Agustín León-Navarro ◽

José Luis Albasanz ◽

Mairena Martín

Keyword(s):

Neurodegenerative Diseases ◽

Adenylyl Cyclase ◽

Glutamate Receptors ◽

G Protein ◽

Metabotropic Glutamate Receptors ◽

Metabotropic Glutamate ◽

Group I ◽

Gene And Protein Expression

G-protein coupled receptors are transmembrane proteins widely expressed in cells and their transduction pathways are mediated by controlling second messenger levels through different G-protein interactions. Many of these receptors have been described as involved in the physiopathology of neurodegenerative diseases and even considered as potential targets for the design of novel therapeutic strategies. Endogenous and synthetic allosteric and orthosteric selective ligands are able to modulate GPCRs at both gene and protein expression levels and can also modify their physiological function. GPCRs that coexist in the same cells can homo- and heteromerize, therefore, modulating their function. Adenosine receptors are GPCRs which stimulate or inhibit adenylyl cyclase activity through Gi/Gs protein and are involved in the control of neurotransmitter release as glutamate. In turn, metabotropic glutamate receptors are also GPCRs which inhibit adenylyl cyclase or stimulate phospholipase C activities through Gi or Gq proteins, respectively. In recent years, evidence of crosstalk mechanisms between different GPCRs have been described. The aim of the present review was to summarize the described mechanisms of interaction and crosstalking between adenosine and metabotropic glutamate receptors, mainly of group I, in both in vitro and in vivo systems, and their possible use for the design of novel ligands for the treatment of neurodegenerative diseases.

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