Wiring and volume transmission in the central nervous system: the concept of closed and open synapses

Zoli, Michèle

doi:10.1016/s0301-0082(96)00020-2

Cited by 104 publications

(37 citation statements)

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“…These investigators have suggested that these mGluRs are not present in the synaptic cleft and that glutamate diffusion from its site of release is required for their activation. Thus, during high quantal release, glutamate could diffuse from several active synapses and reach a concentration sufficiently high to activate extrasynaptic mGluR populations (see Zoli & Agnati 1996 and references therein). This proposition is consistent with the present observations of an mGluR‐mediated suppression of basal DA oxidation currents following either BLA burst stimulation at short IBIs (< 1 s) or repetitive 20 Hz pulse frequencies.…”

Section: Discussionmentioning

confidence: 99%

Association Basolateral amygdala stimulation evokes glutamate receptor‐dependent dopamine efflux in the nucleus accumbens of the anaesthetized rat

Floresco

Yang

Phillips

et al. 1998

Eur J of Neuroscience

150

105

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Afferents from the basolateral amygdala and dopamine projections from the ventral tegmental area to the nucleus accumbens have both been implicated in reward-related processes. The present study used in vivo chronoamperometry with stearate-graphite paste electrodes in urethane-anaesthetized rats to determine how basolateral amygdala efferents to the nucleus accumbens synaptically regulate dopamine efflux. Repetitive-pulse (20 Hz for 10 s) electrical stimulation of the basolateral amygdala evoked a complex pattern of changes in monitored dopamine oxidation currents in the nucleus accumbens related to dopamine efflux. These changes were characterized by an initial increase that was time-locked to stimulation, a secondary decrease below baseline, followed by a prolonged increase in the dopamine signal above baseline. The effects of burst-patterned stimulation (100 Hz, 5 pulses/burst, 1-s interburst interval, 40 s) of the basolateral amygdala on the basal accumbens dopamine signal were similar to those evoked by 20 Hz stimulation, with the lack of a secondary suppressive component. Infusions of the ionotropic glutamate receptor antagonists (+/-)-2-amino-5-phosphonopentanoic acid (APV) or 6,7-dinitroquinoxaline-2,3-dione (DNQX) into the nucleus accumbens dose-dependently blocked or attenuated the initial and prolonged increases in the dopamine signal following 20 Hz or burst-patterned basolateral amygdala stimulation. Infusions of the metabotropic glutamate receptor antagonist (+)-alpha-methyl-4-carboxyphenylglycine selectively blocked the intermediate suppressive effect of 20 Hz basolateral amygdala stimulation on dopamine oxidation currents. Blockade of glutamate receptors or inhibition of dopamine neuronal activity via infusions of either APV + DNQX, lidocaine or gamma-hydroxybutyric acid, respectively, into the ventral tegmental area did not effect the pattern of changes in the accumbens dopamine signal evoked by basolateral amygdala stimulation. These data suggest that the glutamatergic basolateral amygdala inputs to nucleus accumbens dopamine terminals synaptically facilitate or depress dopamine efflux, and these effects are independent of dopamine neuronal firing activity. Moreover, these results imply that changes in nucleus accumbens dopamine levels following presentation of reward-related stimuli may be mediated, in part, by the basolateral amygdala.

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Section: Discussionmentioning

confidence: 99%

Association Basolateral amygdala stimulation evokes glutamate receptor‐dependent dopamine efflux in the nucleus accumbens of the anaesthetized rat

Floresco

Yang

Phillips

et al. 1998

Eur J of Neuroscience

150

105

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“…The ultrastructural analysis, based on transmitter and receptor immunocytochemistry, has repeatedly demonstrated short distance transmitter/receptor mismatches for the DA transmitter with the major part of the D1 and D2 receptor labeling being outside the DA synapses in the local striatal circuits, in which the DA synapses and/or non-junctional DA terminals are found (Dana et al, 1989; Levey et al, 1993; Sesack et al, 1994; Smiley et al, 1994; Hersch et al, 1995, 1997; Yung et al, 1995; Caille et al, 1996; for review see Jansson et al, 2002). The evidence therefore indicates that DA mainly acts as a VT transmitter being directly released into the ECF or reaching it via leaking DA synapses (Fuxe and Agnati, 1991a,b; Zoli and Agnati, 1996; Fuxe et al, 2007a). Rice and Cragg (2008) have modeled DA spillover after quantal release based on a large number of experimental data.…”

Section: Introductionmentioning

confidence: 99%

Extrasynaptic Neurotransmission in the Modulation of Brain Function. Focus on the Striatal Neuronal–Glial Networks

Fuxé¹,

Borroto‐Escuela²,

Romero-Fernández³

et al. 2012

Front. Physio.

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Extrasynaptic neurotransmission is an important short distance form of volume transmission (VT) and describes the extracellular diffusion of transmitters and modulators after synaptic spillover or extrasynaptic release in the local circuit regions binding to and activating mainly extrasynaptic neuronal and glial receptors in the neuroglial networks of the brain. Receptor-receptor interactions in G protein-coupled receptor (GPCR) heteromers play a major role, on dendritic spines and nerve terminals including glutamate synapses, in the integrative processes of the extrasynaptic signaling. Heteromeric complexes between GPCR and ion-channel receptors play a special role in the integration of the synaptic and extrasynaptic signals. Changes in extracellular concentrations of the classical synaptic neurotransmitters glutamate and GABA found with microdialysis is likely an expression of the activity of the neuron-astrocyte unit of the brain and can be used as an index of VT-mediated actions of these two neurotransmitters in the brain. Thus, the activity of neurons may be functionally linked to the activity of astrocytes, which may release glutamate and GABA to the extracellular space where extrasynaptic glutamate and GABA receptors do exist. Wiring transmission (WT) and VT are fundamental properties of all neurons of the CNS but the balance between WT and VT varies from one nerve cell population to the other. The focus is on the striatal cellular networks, and the WT and VT and their integration via receptor heteromers are described in the GABA projection neurons, the glutamate, dopamine, 5-hydroxytryptamine (5-HT) and histamine striatal afferents, the cholinergic interneurons, and different types of GABA interneurons. In addition, the role in these networks of VT signaling of the energy-dependent modulator adenosine and of endocannabinoids mainly formed in the striatal projection neurons will be underlined to understand the communication in the striatal cellular networks.

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“…The ultrastructural analysis based on transmitter and receptor immunocytochemistry has repeatedly demonstrated short distance transmitter/receptor mismatches for the DA transmitter with the major part of the D 1 and D 2 receptor labeling being outside the DA synapses in the local striatal circuits in which the DA synapses are found (Caille et al,1996; Dana et al,1989; Hersch et al,1995; Levey et al,1993; Sesack et al,1994; Smiley et al,1994; Yung et al,1995). The evidence therefore indicates that DA mainly acts as a VT transmitter being directly released into the extracellular fluid or reaching it via leaking DA synapses (Fuxe and Agnati,1991b; Fuxe et al,2007; Zoli and Agnati,1996).…”

Section: Introductionmentioning

confidence: 99%

Increased affinity of dopamine for D₂‐like versus D₁‐like receptors. Relevance for volume transmission in interpreting PET findings

Marcellino

Kehr

Agnati

et al. 2011

Synapse

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Evidence indicates that dopamine (DA) mainly acts as a volume transmission (VT) transmitter through its release into the extracellular fluid where the D(1) -like and D(2) -like receptors are predominantly extrasynaptic. It was therefore of interest to compare the affinities of the two major families of DA receptors. [(3)H] raclopride /DA and [(3)H] SCH23390/DA competition assays compared the affinity of DA at D(2) -like and D(1) -like receptors in rat dorsal striatal membrane preparations as well as in membrane preparations from CHO cell lines stably transfected with human D(2L) and D(1) receptors. The IC(50) values of DA at D(2) -like receptors in dorsal striatal membranes and CHO cell membranes were markedly and significantly reduced compared with the IC(50) values of DA at D(1) -like receptors. These IC(50) values reflect differences in both the high and low affinity states. The K(iH) value for DA at [(3)H] raclopride-labeled D(2) -like receptors in dorsal striatum was 12 nM, and this can help explain PET findings that amphetamine-induced increases in DA release can produce an up to 50% decrease of [(11)C] raclopride binding in the dorsal striatum in vivo. These combined results give indications for the existence of striatal D(2) -like receptor-mediated DA VT at the local circuit level in vivo. The demonstration of a K(iH) value of 183 nM for DA at D(1) antagonist-labeled D(1) -like receptors instead gives a likely explanation for the failure of a reduction of D(1) -like receptor binding after amphetamine-induced DA release in PET studies using the D(1) -like antagonist radioligands [(11)C] SCH23390 and [(11)C] NNC. It seems difficult to evaluate the role of the extrasynaptic D(1) receptors in VT in vivo with the PET radioligands available for this receptor.

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Wiring and volume transmission in the central nervous system: the concept of closed and open synapses

Cited by 104 publications

References 0 publications

Association Basolateral amygdala stimulation evokes glutamate receptor‐dependent dopamine efflux in the nucleus accumbens of the anaesthetized rat

Association Basolateral amygdala stimulation evokes glutamate receptor‐dependent dopamine efflux in the nucleus accumbens of the anaesthetized rat

Extrasynaptic Neurotransmission in the Modulation of Brain Function. Focus on the Striatal Neuronal–Glial Networks

Increased affinity of dopamine for D₂‐like versus D₁‐like receptors. Relevance for volume transmission in interpreting PET findings

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Wiring and volume transmission in the central nervous system: the concept of closed and open synapses

Cited by 104 publications

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Association Basolateral amygdala stimulation evokes glutamate receptor‐dependent dopamine efflux in the nucleus accumbens of the anaesthetized rat

Association Basolateral amygdala stimulation evokes glutamate receptor‐dependent dopamine efflux in the nucleus accumbens of the anaesthetized rat

Extrasynaptic Neurotransmission in the Modulation of Brain Function. Focus on the Striatal Neuronal–Glial Networks

Increased affinity of dopamine for D2‐like versus D1‐like receptors. Relevance for volume transmission in interpreting PET findings

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Increased affinity of dopamine for D₂‐like versus D₁‐like receptors. Relevance for volume transmission in interpreting PET findings