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Winland CD, Welsh N, Sepulveda-Rodriguez A, Vicini S, Maguire-Zeiss KA. Inflammation alters AMPA-stimulated calcium responses in dorsal striatal D2 but not D1 spiny projection neurons. Eur J Neurosci 2017; 46:2519-2533. [PMID: 28921719 PMCID: PMC5673553 DOI: 10.1111/ejn.13711] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 12/22/2022]
Abstract
Neuroinflammation precedes neuronal loss in striatal neurodegenerative diseases and can be exacerbated by the release of proinflammatory molecules by microglia. These molecules can affect trafficking of AMPARs. The preferential trafficking of calcium-permeable versus impermeable AMPARs can result in disruptions of [Ca2+ ]i and alter cellular functions. In striatal neurodegenerative diseases, changes in [Ca2+ ]i and L-type voltage-gated calcium channels (VGCCs) have been reported. Therefore, this study sought to determine whether a proinflammatory environment alters AMPA-stimulated [Ca2+ ]i through calcium-permeable AMPARs and/or L-type VGCCs in dopamine-2- and dopamine-1-expressing striatal spiny projection neurons (D2 and D1 SPNs) in the dorsal striatum. Mice expressing the calcium indicator protein, GCaMP in D2 or D1 SPNs, were utilized for calcium imaging. Microglial activation was assessed by morphology analyses. To induce inflammation, acute mouse striatal slices were incubated with lipopolysaccharide (LPS). Here we report that LPS treatment potentiated AMPA responses only in D2 SPNs. When a nonspecific VGCC blocker was included, we observed a decrease of AMPA-stimulated calcium fluorescence in D2 but not D1 SPNs. The remaining agonist-induced [Ca2+ ]i was mediated by calcium-permeable AMPARs because the responses were completely blocked by a selective calcium-permeable AMPAR antagonist. We used isradipine, the highly selective L-type VGCC antagonist to determine the role of L-type VGCCs in SPNs treated with LPS. Isradipine decreased AMPA-stimulated responses selectively in D2 SPNs after LPS treatment. Our findings suggest that dorsal striatal D2 SPNs are specifically targeted in proinflammatory conditions and that L-type VGCCs and calcium-permeable AMPARs are important mediators of this effect.
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MESH Headings
- Animals
- CX3C Chemokine Receptor 1/genetics
- CX3C Chemokine Receptor 1/metabolism
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/metabolism
- Cations, Divalent/metabolism
- Corpus Striatum/drug effects
- Corpus Striatum/metabolism
- Corpus Striatum/pathology
- Dopaminergic Neurons/drug effects
- Dopaminergic Neurons/metabolism
- Dopaminergic Neurons/pathology
- Female
- Inflammation/metabolism
- Inflammation/pathology
- Lipopolysaccharides
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Microglia/drug effects
- Microglia/metabolism
- Microglia/pathology
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/metabolism
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Tissue Culture Techniques
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/metabolism
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Affiliation(s)
- Carissa D. Winland
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
| | - Nora Welsh
- Department of Biology, Georgetown University, Washington, D.C. 20007 USA
| | - Alberto Sepulveda-Rodriguez
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C. 20007 USA
| | - Stefano Vicini
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C. 20007 USA
| | - Kathleen A. Maguire-Zeiss
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Biology, Georgetown University, Washington, D.C. 20007 USA
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2
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Nassery K, Marino V, Parker DAS. Uptake and release of [(3)H]GABA in human dental pulp. Arch Oral Biol 2007; 52:607-13. [PMID: 17276385 DOI: 10.1016/j.archoralbio.2006.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 11/14/2006] [Accepted: 12/06/2006] [Indexed: 11/24/2022]
Abstract
The purpose of this study was to determine whether (a) an uptake system for gamma-aminobutyric acid (GABA) exists in human dental pulp, (b) GABA can be released from nerves in this tissue, and (c) GABA(B) autoreceptors modulate release of this transmitter. Segments of vital pulp were incubated in [(3)H]GABA (0.1-10 microM) for up to 120 min, washed, and the retained [(3)H] extracted and assayed. Some tissues were treated with GABA uptake inhibitors (nipecotic acid or NO-711) prior to incubation. At concentrations of 0.1 and 1.0 microM the uptake of [(3)H]GABA was saturated after 90 min of incubation. At 10 microM, at least two uptake compartments were apparent, and the amount of [(3)H]GABA retained was five-fold greater than 0.1 microM. The uptake inhibitors reduced [(3)H]GABA accumulation by more than 80%. In the release study, pulp was incubated in [(3)H]GABA (0.5 microM) for 90 min, and superfused with Krebs solution containing NO-711 (5 microM). Electrical stimulation increased the overflow of [(3)H]; a GABA(B) autoreceptor agonist (baclofen) inhibited, whilst an antagonist, Sch 50911, enhanced this release. The effects of baclofen were reversed by Sch 50911. These results imply that GABA can be taken up and bound firmly in compartments within human dental pulp, GABA can be released from isolated pulp segments by electrical stimulation, and this release is modulated by GABA(B) autoreceptors.
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Affiliation(s)
- Khashayar Nassery
- School of Dentistry, The University of Adelaide University, Adelaide, South Australia 5005, Australia
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3
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Hauber W, Neuscheler P, Nagel J, Müller CE. Catalepsy induced by a blockade of dopamine D1 or D2 receptors was reversed by a concomitant blockade of adenosine A(2A) receptors in the caudate-putamen of rats. Eur J Neurosci 2001; 14:1287-93. [PMID: 11703457 DOI: 10.1046/j.0953-816x.2001.01759.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study sought to determine, in more detail, the effects of an unselective and a selective adenosine A(2A) receptor blockade on catalepsy induced by a blockade of dopamine D1 or D2 receptors in rats. The results demonstrated that systemic administration of the unselective A1/A2 receptor antagonist, theophylline and the selective A(2A) receptor antagonist, CSC potently reversed catalepsy induced by a systemic D2 receptor blockade with raclopride or by a bilateral blockade of D2 receptors in the caudate-putamen (CPu) with S(-)sulpiride. Likewise, systemic administration of theophylline and CSC reversed catalepsy induced by a systemic D1 receptor blockade with SCH23390; theophylline also counteracted catalepsy after an intra-CPu D1 receptor blockade with SCH23390. Intracerebral co-microinfusions of the selective A(2A) receptor antagonist, MSX-3 together with a D1 (SCH23390) or D2 receptor [S(-) sulpiride] antagonist revealed that catalepsy due to intra-CPu D1 or D2 receptor blockade can be potently reversed by an intra-CPu A2A receptor blockade. In conclusion, our results with systemic and intra-CPu drug administration demonstrate that D1 and D2 receptor-mediated catalepsy can both be reversed by a concomitant blockade of A(2A) receptors. Our results implicate that the CPu is a critical neural substrate for antagonistic interactions of a D1/D2 receptor blockade and an A(2A) receptor blockade in control of motor activity. The present results provide further support for the view that A(2A) receptor antagonists may be potential therapeutics for the treatment of Parkinson's disease.
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Affiliation(s)
- W Hauber
- Department of Animal Physiology, Institute of Biology, University of Stuttgart, D-70550 Stuttgart, Germany.
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4
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Functional uncoupling of adenosine A(2A) receptors and reduced responseto caffeine in mice lacking dopamine D2 receptors. J Neurosci 2000. [PMID: 10934242 DOI: 10.1523/jneurosci.20-16-05949.2000] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dopamine D(2) receptors (Rs) and adenosine A(2A)Rs are coexpressed on striatopallidal neurons, where they mediate opposing actions. In agreement with the idea that D(2)Rs tonically inhibit GABA release from these neurons, stimulation-evoked GABA release was significantly greater from striatal/pallidal slices from D(2)R null mutant (D(2)R(-/-)) than from wild-type (D(2)R(+/+)) mice. Release from heterozygous (D(2)R(+/-)) slices was intermediate. However, contrary to predictions that A(2A)R effects would be enhanced in D(2)R-deficient mice, the A(2A)R agonist CGS 21680 significantly increased GABA release only from D(2)R(+/+) slices. CGS 21680 modulation was observed when D(2)Rs were antagonized by raclopride, suggesting that an acute absence of D(2)Rs cannot explain the results. The lack of CGS 21680 modulation in the D(2)R-deficient mice was also not caused by a compensatory downregulation of A(2A)Rs in the striatum or globus pallidus. However, CGS 21680 significantly stimulated cAMP production only in D(2)R(+/+) striatal/pallidal slices. This functional uncoupling of A(2A)Rs in the D(2)R-deficient mice was not explained by reduced expression of G(s), G(olf), or type VI adenylyl cyclase. Locomotor activity induced by the adenosine receptor antagonist caffeine was significantly less pronounced in D(2)R(-/-) mice than in D(2)R(+/+) and D(2)R(+/-) mice, further supporting the idea that D(2)Rs are required for caffeine activation. Caffeine increased c-fos only in D(2)R(-/-) globus pallidus. The present results show that a targeted disruption of the D(2)R reduces coupling of A(2A)Rs on striatopallidal neurons and thereby responses to drugs that act on adenosine receptors. They also reinforce the ideas that D(2)Rs and A(2A)Rs are functionally opposed and that D(2)R-mediated effects normally predominate.
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5
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Abstract
The magnitude of behavioral sensitization to cocaine is correlated with decreased striatal GABA(A) receptor function. We examined whether GABA release from striatal slices is also altered in cocaine-treated rats. Behavioral sensitization was measured in rats receiving either saline or cocaine (15 mg kg(-1)) daily for 14 days. Cocaine-treated rats showed a significant increase in locomotion and stereotypy over days. Potassium-stimulated endogenous GABA release was measured from superfused striatal slices of these rats. GABA release was significantly decreased in cocaine-treated rats. However, striatal slices preloaded with [(3)H]GABA exhibited a slight but significant increase in release after cocaine sensitization. Similar treatment with a nonsensitizing dose of cocaine (7.5 mg kg(-1)) did not change endogenous GABA release. Saline- and cocaine-treated rats showed no differences in striatal glutamic acid decarboxylase activity at either a saturating or K(m) concentration of glutamate. Therefore, the decrease in endogenous GABA release is not due to a decrease in GABA synthesis, but may reflect changes in GABA storage pools. These data are consistent with an overall decrease in GABA transmission, both pre- and postsynaptically, in the striatum of sensitized rats, which could contribute to enhanced striatal output and behavioral sensitization.
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Affiliation(s)
- B J Jung
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, USA.
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6
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Mayfield RD, Jones BA, Miller HA, Simosky JK, Larson GA, Zahniser NR. Modulation of endogenous GABA release by an antagonistic adenosine A1/dopamineD1 receptor interaction in rat brain limbic regions but not basal ganglia. Synapse 1999; 33:274-81. [PMID: 10421708 DOI: 10.1002/(sici)1098-2396(19990915)33:4<274::aid-syn4>3.0.co;2-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Behavioral and biochemical studies suggest that a negative interaction exists between adenosine A(1) and dopamine D(1) receptors in the brain and that this may contribute to the psychomotor effects of adenosine receptor agonists and antagonists. We examined the functional significance of A(1) and D(1) receptor subtypes in modulating electrically evoked endogenous GABA release from slices/punches of rat basal ganglia (striatum, globus pallidus, striatum containing globus pallidus, and substantia nigra reticulata) and limbic regions (ventral pallidum and nucleus accumbens). In basal ganglia, stimulation of A(1) receptors with the selective agonist R-PIA (1-100 nM) resulted in a concentration-dependent decrease in GABA release. The selective A(1) antagonist DPCPX (10-100 nM) increased GABA release, suggesting that endogenous adenosine tonically inhibits GABA release. However, in basal ganglia, consistent dopamine D(1) receptor modulation of GABA, release was not observed in response to either D(1) agonists or antagonists. Furthermore, the A(1) receptor-mediated inhibition of GABA release was not changed by concurrent activation of D(1) receptors, thus confirming the lack of D(1) receptor modulation under these conditions. In contrast, in ventral pallidum and nucleus accumbens, stimulation of D(1) receptors with SKF-82958 (1 microM) increased GABA release significantly. The D(1) receptor-mediated increase in GABA release was attenuated by concurrent activation of adenosine A(1) receptors. These results are consistent with the hypothesis that an antagonistic A(1)/D(1) receptor interaction may be important in modulating GABA release in limbic regions.
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Affiliation(s)
- R D Mayfield
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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7
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Bianchi L, Della Corte L, Tipton KF. Simultaneous determination of basal and evoked output levels of aspartate, glutamate, taurine and 4-aminobutyric acid during microdialysis and from superfused brain slices. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 723:47-59. [PMID: 10080632 DOI: 10.1016/s0378-4347(98)00519-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A HPLC method, involving pre-column derivatisation with o-phthalaldehyde and fluorescence detection, is described. It allows the resolution of aspartate, glutamate, taurine and GABA, in a single run with detection limits of 3.2, 1.7, 1.4 and 2 fmol/microl of perfusate, respectively. It is sufficiently sensitive and rapid (15 min) for the determination "on line" of the four amino acids in perfusates obtained during in vivo microdialysis experiments. The procedure has been used to determine basal, K+ - or veratridine-stimulated release of these amino acids in different brain areas during microdialysis and from perfused tissue slices.
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Affiliation(s)
- L Bianchi
- Dipartimento di Farmacologia Preclinica e Clinica M. Aiazzi Mancini, Firenze, Italy
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8
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Kash SF, Johnson RS, Tecott LH, Noebels JL, Mayfield RD, Hanahan D, Baekkeskov S. Epilepsy in mice deficient in the 65-kDa isoform of glutamic acid decarboxylase. Proc Natl Acad Sci U S A 1997; 94:14060-5. [PMID: 9391152 PMCID: PMC28432 DOI: 10.1073/pnas.94.25.14060] [Citation(s) in RCA: 249] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/1997] [Indexed: 02/05/2023] Open
Abstract
gamma-Aminobutyric acid (GABA), the major inhibitory neurotransmitter in the mammalian brain, is synthesized by two glutamate decarboxylase isoforms, GAD65 and GAD67. The separate role of the two isoforms is unknown, but differences in saturation with cofactor and subcellular localization suggest that GAD65 may provide reserve pools of GABA for regulation of inhibitory neurotransmission. We have disrupted the gene encoding GAD65 and backcrossed the mutation into the C57BL/6 strain of mice. In contrast to GAD67-/- animals, which are born with developmental abnormalities and die shortly after birth, GAD65-/- mice appear normal at birth. Basal GABA levels and holo-GAD activity are normal, but the pyridoxal 5' phosphate-inducible apo-enzyme reservoir is significantly decreased. GAD65-/- mice develop spontaneous seizures that result in increased mortality. Seizures can be precipitated by fear or mild stress. Seizure susceptibility is dramatically increased in GAD65-/- mice backcrossed into a second genetic background, the nonobese diabetic (NOD/LtJ) strain of mice enabling electroencephalogram analysis of the seizures. The generally higher basal brain GABA levels in this backcross are significantly decreased by the GAD65-/- mutation, suggesting that the relative contribution of GABA synthesized by GAD65 to total brain GABA levels is genetically determined. Seizure-associated c-fos-like immunoreactivity reveals the involvement of limbic regions of the brain. These data suggest that GABA synthesized by GAD65 is important in the dynamic regulation of neural network excitability, implicate at least one modifier locus in the NOD/LtJ strain, and present GAD65-/- animals as a model of epilepsy involving GABA-ergic pathways.
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Affiliation(s)
- S F Kash
- Department of Medicine, School of Medicine, University of California at San Francisco, San Francisco, CA 94143, USA
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9
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Peris J, Eppler B, Hu M, Walker DW, Hunter BE, Mason K, Anderson KJ. Effects of Chronic Ethanol Exposure on GABA Receptors and GABAB Receptor Modulation of 3H-GABA Release in the Hippocampus. Alcohol Clin Exp Res 1997. [DOI: 10.1111/j.1530-0277.1997.tb04252.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Harsing LG, Zigmond MJ. Influence of dopamine on GABA release in striatum: evidence for D1-D2 interactions and non-synaptic influences. Neuroscience 1997; 77:419-29. [PMID: 9472401 DOI: 10.1016/s0306-4522(96)00475-7] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Striatal slices from the rat were preincubated with [3H]GABA and superfused in the presence of nipecotic acid and aminooxyacetic acid, inhibitors of high-affinity GABA transport and GABA aminotransferase, respectively. GABA efflux was estimated by monitoring tritium efflux, 98% of which was in the form of [3H]GABA. The following three major observations were made: (1) The overflow of GABA evoked by electrical field stimulation (8 Hz) was increased two-fold by SKF-38393 (10 microM), an agonist at the D1 family of dopamine receptors. This increase was completely blocked by the D1 receptor antagonist SCH-23390 (10 microM). However, SCH-23390 had no effect on GABA overflow when given alone. Thus, dopamine agonists appear to exert an excitatory influence on GABA release; however, this effect was not elicited by endogenous dopamine under the conditions of this experiment. (2) Electrically evoked GABA overflow was reduced 50% by quinpirole (10 microM), an agonist at the D2 family of dopamine receptors, and this effect was blocked by the D2 antagonist sulpiride (10 microM). Moreover, exposure to sulpiride alone caused a 60% increase in GABA overflow, and this effect was abolished by 3-iodotyrosine (2 mM), a dopamine synthesis inhibitor. Thus, D2 agonists appear to exert an inhibitory influence on dopamine release, an effect that can be exerted by endogenous stores of dopamine. (3) The stimulatory effect of SKF-38393 was attenuated by quinpirole, whereas the sulpiride-induced increase in GABA efflux was attenuated by SCH-23390. Sulpiride also increased [3H]GABA efflux during KCl-induced depolarization, an effect that was antagonized by SCH-23390 as in the case of electrical stimulation. However, although tetrodotoxin did not alter the stimulatory effect of sulpiride, it did block the ability of SCH-23390 to antagonize the sulpiride-induced increase in GABA overflow. These latter results suggest that there is an interaction between D1 and D2 receptors whereby the effects of dopamine mediated via D1 sites are inhibited by an action on D2 sites. In conclusion, our results suggest that (i) dopamine agonists can exert an excitatory influence on depolarization-induced GABA release within neostriatum via D1 receptors and an inhibitory influence via D2 receptors; (ii) under the conditions of these experiments, endogenous dopamine fails to act on D1 sites but does exert an inhibitory influence via D2 sites; and (iii) there is an interaction between D1 and D2 receptors such that the actions of dopamine mediated via D1 sites are inhibited as a result of the concomitant actions exerted via D2 sites.
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Affiliation(s)
- L G Harsing
- Department of Neuroscience, University of Pittsburgh, PA 15260, USA
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11
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Dayne Mayfield R, Larson G, Orona RA, Zahniser NR. Opposing actions of adenosine A2a and dopamine D2 receptor activation on GABA release in the basal ganglia: evidence for an A2a/D2 receptor interaction in globus pallidus. Synapse 1996; 22:132-8. [PMID: 8787129 DOI: 10.1002/(sici)1098-2396(199602)22:2<132::aid-syn6>3.0.co;2-e] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
There is increasing evidence that adenosine (ADO) and dopamine (DA) interact directly in the basal ganglia via actions at ADO A2a and DA D2 receptors, respectively. The purpose of this study was to determine 1) the extent to which these receptors modulate endogenous GABA release in discrete regions of the rat basal ganglia and 2) whether GABA release is modulated by a direct and opposing interaction between ADO A2a and DA D2 receptors. Tissue slices of striatum (STR) containing globus pallidus (GP; STR/GP) and micropunches of STR, GP, and substantia nigra pars reticulata (SNr) were studied. Radioligand binding demonstrated that ADO A1, ADO A2a, and DA D2 receptors were present in each of the tissue preparations with the exception of SNr, in which ADO A2a receptors were not detected. Stimulation of ADO A2a receptors with CGS 21680 (1-10 nM) increased electrically stimulated GABA release in STR/GP slices and GP micropunches. Consistent with the lack of A2a receptors in SNr, CGS 21680 had no effect on GABA release from this region. In contrast, stimulation of DA D2 receptors with N-0437 (1-100 nM) inhibited evoked GABA release from STR/GP slices and both GP and SNr micropunches. The D2-mediated inhibition of GABA release in GP was abolished in the presence of CGS 21680 (10 nM). These experiments demonstrate that stimulation of ADO A2a and DA D2 receptors has opposing effects on endogenous GABA release in STR and GP. These opposing actions may explain the antagonistic interactions between ADO and DA that have been observed in behavioral studies and support the hypothesis that the striatopallidal efferent system is an important anatomical substrate for the A2a/D2 receptor interaction.
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Affiliation(s)
- R Dayne Mayfield
- Department of Pharmacology and Neuroscience Program, University of Colorado Health Sciences Center, Denver 80262, USA
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12
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Ishige K. Age-related changes in [3H]baclofen binding in mouse cerebellum. GENERAL PHARMACOLOGY 1995; 26:1229-35. [PMID: 7590111 DOI: 10.1016/0306-3623(95)00023-t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
1. Specific [3H]baclofen binding to cerebellar membranes from 1-month-old (young), 8-month-old (older) and 20-month-old (aged) mice was lower than that to membranes from 3-month-old mice (mature adult), whereas in cerebral cortical membranes there were no age-related changes in [3H]baclofen binding among the four age groups. 2. Scatchard analysis revealed that the density of cerebellar GABAB receptors significantly decreased during aging. 3. There were no age-related changes in the inhibitory effect of Gpp(NH)p on [3H]baclofen binding. 4. These results suggest that the characteristics of GABAB receptors in the cerebellum change during aging without any alteration in the coupling of the receptor to guanine nucleotide regulatory proteins.
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Affiliation(s)
- K Ishige
- Department of Pharmacology, College of Pharmacy, Nihon University, Chiba, Japan
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