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Tebano MT, Martire A, Popoli P. Adenosine A(2A)-cannabinoid CB(1) receptor interaction: an integrative mechanism in striatal glutamatergic neurotransmission. Brain Res 2012; 1476:108-18. [PMID: 22565012 DOI: 10.1016/j.brainres.2012.04.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 12/12/2022]
Abstract
The striatum is a subcortical area involved in sensorimotor, cognitive and emotional processes. Adenosine A(2A) receptors (A(2A)Rs) are highly expressed in the striatum, and their ability to establish functional and molecular interactions with many other receptors attributes to a pivotal role in the modulation and integration of striatal neurotransmission. This review will focus on the interaction between A(2A)Rs and cannabinoid CB(1) receptors (CB(1)Rs), taking it as a paradigmatic example of synaptic integration. Indeed, A(2A)Rs can exert an opposite (permissive vs. inhibitory) influence on CB1-dependent synaptic effect. These apparently irreconcilable functions could depend on a different role of pre- vs. postsynaptic A(2A)Rs, on their interaction with other receptors (namely adenosine A(1), metabotropic glutamate 5 and dopamine D2 receptors), and on whether A(2A)Rs form or not heteromers with CB(1)Rs. Besides providing a good example of the intricate pattern of events taking place in striatal synapses, the A(2A)/CB(1)R interaction proves very informative to understand the physiology of the basal ganglia and the mechanisms of related diseases. This article is part of a Special Issue entitled: Brain Integration.
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Affiliation(s)
- Maria Teresa Tebano
- Section of Central Nervous System Pharmacology, Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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102
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Akula KK, Kulkarni SK. Adenosinergic system: an assorted approach to therapeutics for drug addiction. FUTURE NEUROLOGY 2012. [DOI: 10.2217/fnl.12.19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Adenosine is an endogenous purine nucleoside and it is extensively present in the brain. It exerts several metabolic and neuromodulatory roles in the body. Adenosine also acts as an important messenger molecule for extracellular signaling and shows a homeostatic neuromodulatory function at the synaptic level. Extracellular adenosine exerts a wide variety of biological actions through four cell surface G-protein-coupled receptor subtypes, namely A1, A2A, A2B and A3 adenosine receptors. The extracellular levels of adenosine have been found to be enhanced in several neuropathological conditions, including drug addiction, and thus a neuroprotective role of adenosine was perceived by various experimental studies. The aversive withdrawal symptoms emanating from drug discontinuation provokes rebound drug intake patterns. In addition, alteration of neurotransmitter(s) release and changes in receptor expression contribute to the behavioral changes of drug withdrawal. Furthermore, the abuse of major drugs such as alcohol and opioids are reported to modulate extracellular adenosine levels. In this context, the neuromodulatory functions of adenosine would be valuable if projected to the clinical applications and thus, an increasing attention is currently given to the functional role of adenosine in human addictive disorders. This review will focus on recent clinical and experimental studies that reveal the actions of adenosine and related ligands in drug addiction and various drug-withdrawal syndromes. The evidence and reports provided in this review highlight the looming therapeutic potential of purinergic drugs, with a hope that new therapeutic interventions based on the adenosinergic concept will emerge in the coming years for the management of drug withdrawal syndrome.
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Affiliation(s)
- Kiran Kumar Akula
- R.S. Dow Neurobiology Laboratories, Legacy Research, 1225 NE 2nd Avenue, Portland, OR 97232, USA
| | - SK Kulkarni
- Pharmacology Division, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh-160014, India
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103
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Constitutive activity of the A2A adenosine receptor and compartmentalised cyclic AMP signalling fine-tune noradrenaline release. Purinergic Signal 2012; 8:677-92. [PMID: 22476939 DOI: 10.1007/s11302-012-9298-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 03/09/2012] [Indexed: 10/28/2022] Open
Abstract
Neuroblastoma SH-SY5Y (SH) cells endogenously express A(2A) adenosine receptors and can be differentiated into a sympathetic neuronal phenotype, capable of depolarisation-dependent noradrenaline release. Using differentiated SH culture, we here explored the link between A(2A)-receptor signalling and neurotransmitter release. In response to the receptor agonist CGS21680, the cells produced cyclic AMP (cAMP), and when depolarised, they released increased amounts of noradrenaline. An A(2A)-receptor antagonist, XAC, as well as an inhibitor of cAMP-dependent protein kinase A (PKA), H89, depressed agonist-dependent release. In the presence of XAC or H89, noradrenaline release was found to be below basal values. This suggested that release facilitation also owes to constitutive receptor activity. We demonstrate that even in the absence of an agonist, the native A(2A)-receptor stimulated cAMP production, leading to the activation of PKA and enhanced noradrenaline release. Ancillary, non-cAMP-dependent effects of the receptor (i.e. phosphorylation of CREB, of Rabphilin3A) were refractory to constitutive activation. PKA-dependent facilitation of noradrenaline release was recapitulated with membrane-permeable 8-Br-cAMP; in addition to facilitation, 8-Br-cAMP caused marked inhibition of release, an effect not observed upon receptor activation. Inhibition by receptor-independent cAMP was likely due to suppression of voltage-dependent calcium current (VDCC) and increased activity of Src-family kinases. Receptor-mediated release facilitation was reproduced in the presence of tetrodotoxin (blocking action potentials); hence, the signalling occurred at the active zone comprising release sites. Our findings thus support (1) presynaptic localisation of the A(2A)-receptor and (2) suggest that compartmentalised pathways transmit cAMP signalling in order to facilitate depolarisation-dependent neurotransmitter release.
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104
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Moeller FG, Steinberg JL, Lane SD, Kjome KL, Ma L, Ferre S, Schmitz JM, Green CE, Bandak SI, Renshaw PF, Kramer LA, Narayana PA. Increased Orbitofrontal Brain Activation after Administration of a Selective Adenosine A(2A) Antagonist in Cocaine Dependent Subjects. Front Psychiatry 2012; 3:44. [PMID: 22654774 PMCID: PMC3361057 DOI: 10.3389/fpsyt.2012.00044] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 04/22/2012] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Positron Emission Tomography imaging studies provide evidence of reduced dopamine function in cocaine dependent subjects in the striatum, which is correlated with prefrontal cortical glucose metabolism, particularly in the orbitofrontal cortex. However, whether enhancement of dopamine in the striatum in cocaine dependent subjects would be associated with changes in prefrontal cortical brain activation is unknown. One novel class of medications that enhance dopamine function via heteromer formation with dopamine receptors in the striatum is the selective adenosine A(2A) receptor antagonists. This study sought to determine the effects administration of the selective adenosine A(2A) receptor antagonist SYN115 on brain function in cocaine dependent subjects. METHODOLOGY/PRINCIPLE FINDINGS Twelve cocaine dependent subjects underwent two fMRI scans (one after a dose of placebo and one after a dose of 100 mg of SYN115) while performing a working memory task with three levels of difficulty (3, 5, and 7 digits). fMRI results showed that for 7-digit working memory activation there was significantly greater activation from SYN115 compared to placebo in portions of left (L) lateral orbitofrontal cortex, L insula, and L superior and middle temporal pole. CONCLUSION/SIGNIFICANCE These findings are consistent with enhanced dopamine function in the striatum in cocaine dependent subjects via blockade of adenosine A(2A) receptors producing increased brain activation in the orbitofrontal cortex and other cortical regions. This suggests that at least some of the changes in brain activation in prefrontal cortical regions in cocaine dependent subjects may be related to altered striatal dopamine function, and that enhancement of dopamine function via adenosine A(2A) receptor blockade could be explored further for amelioration of neurobehavioral deficits associated with chronic cocaine use.
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Affiliation(s)
- F Gerard Moeller
- Department of Psychiatry and Behavioral Sciences, Center for Neurobehavioral Research on Addiction, University of Texas Health Science Center at Houston Houston, TX, USA
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105
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Diversity of metabotropic glutamate receptor-interacting proteins and pathophysiological functions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:63-79. [PMID: 22351051 DOI: 10.1007/978-3-7091-0932-8_3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In the mammalian brain, the large majority of excitatory synapses express pre- and postsynaptic glutamate receptors. These are ion channels and G protein-coupled membrane proteins that are organized into functional signaling complexes. Here, we will review the nature and pathophysiological functions of the scaffolding proteins associated to these receptors, focusing on the G protein-coupled subtypes.
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106
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Fukunaga K, Shioda N. Novel dopamine D2 receptor signaling through proteins interacting with the third cytoplasmic loop. Mol Neurobiol 2011; 45:144-52. [PMID: 22183739 DOI: 10.1007/s12035-011-8227-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 12/07/2011] [Indexed: 01/09/2023]
Abstract
The diverse activities of dopamine D2-like receptors, including D2, D3, and D4 receptors, are mediated by proteins that interact with the third cytoplasmic loop and regulate receptor signaling, receptor trafficking, and apoptosis. Such interacting proteins include calmodulin, the N-methyl-D: -aspartate receptor 2B subunit, calcium/calmodulin-dependent protein kinase II, prostate apoptosis response-4, and β-arrestins, which regulate receptor signaling and the pharmacological action through D2 receptor. The gene encoding the D2 receptor gives rise to two isoforms, termed the dopamine D2 receptor long isoform (D2L) and the dopamine D2 receptor short isoform; the latter lacks 29 amino acids of the D2L receptor within the third cytoplasmic loop. In this review, we first focus on novel functions of the hetero-oligomeric D1/D2 and D2/adenosine A(2A) receptors. We next discuss novel signaling through proteins interacting with the D2 receptor third cytoplasmic loop and define the function of a novel binding protein, heart-type fatty acid binding protein, which interacts with the D2L third cytoplasmic loop.
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Affiliation(s)
- Kohji Fukunaga
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki-Aoba Aoba-ku, Sendai 980-8578, Japan.
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107
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Al-Hasani R, Foster J, Metaxas A, Ledent C, Hourani S, Kitchen I, Chen Y. Increased desensitization of dopamine D2 receptor-mediated response in the ventral tegmental area in the absence of adenosine A2A receptors. Neuroscience 2011; 190:103-11. [DOI: 10.1016/j.neuroscience.2011.05.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 05/10/2011] [Accepted: 05/27/2011] [Indexed: 11/24/2022]
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108
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Ferré S, O'Brien MC. Alcohol and Caffeine: The Perfect Storm. JOURNAL OF CAFFEINE RESEARCH 2011; 1:153-162. [PMID: 24761263 DOI: 10.1089/jcr.2011.0017] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Although it is widely believed that caffeine antagonizes the intoxicating effects of alcohol, the molecular mechanisms underlying their interaction are incompletely understood. It is known that both caffeine and alcohol alter adenosine neurotransmission, but the relationship is complex, and may be dose dependent. In this article, we review the available literature on combining caffeine and alcohol. Ethical constraints prohibit laboratory studies that would mimic the high levels of alcohol intoxication achieved by many young people in real-world settings, with or without the addition of caffeine. We propose a possible neurochemical mechanism for the increase in alcohol consumption and alcohol-related consequences that have been observed in persons who simultaneously consume caffeine. Caffeine is a nonselective adenosine receptor antagonist. During acute alcohol intake, caffeine antagonizes the "unwanted" effects of alcohol by blocking the adenosine A1 receptors that mediate alcohol's somnogenic and ataxic effects. The A1 receptor-mediated "unwanted" anxiogenic effects of caffeine may be ameliorated by alcohol-induced increase in the extracellular concentration of adenosine. Moreover, by means of interactions between adenosine A2A and dopamine D2 receptors, caffeine-mediated blockade of adenosine A2A receptors can potentiate the effects of alcohol-induced dopamine release. Chronic alcohol intake decreases adenosine tone. Caffeine may provide a "treatment" for the withdrawal effects of alcohol by blocking the effects of upregulated A1 receptors. Finally, blockade of A2A receptors by caffeine may contribute to the reinforcing effects of alcohol.
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Affiliation(s)
- Sergi Ferré
- CNS Receptor-Receptor Interactions Unit, National Institute on Drug Abuse , Intramural Research Program, Department of Health and Human Services, Baltimore, Maryland
| | - Mary Claire O'Brien
- Department of Emergency Medicine, Wake Forest School of Medicine , Winston-Salem, North Carolina. ; Department of Social Sciences & Health Policy, Wake Forest School of Medicine , Winston-Salem, North Carolina
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109
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Orrú M, Zanoveli JM, Quiroz C, Nguyen HP, Guitart X, Ferré S. Functional changes in postsynaptic adenosine A(2A) receptors during early stages of a rat model of Huntington disease. Exp Neurol 2011; 232:76-80. [PMID: 21867705 DOI: 10.1016/j.expneurol.2011.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 07/27/2011] [Accepted: 08/08/2011] [Indexed: 10/17/2022]
Abstract
Huntington disease (HD) is a neurodegenerative disorder involving preferential loss of striatal GABAergic medium spiny neurons. Adenosine A(2A) receptors (A(2A)Rs) are present in the striatum at both presynaptic and post-synaptic levels. Blocking pre-synaptic A(2A)Rs, localized in glutamatergic terminals that contact striatal GABAergic dynorphinergic neurons, reduces glutamate release, which could be beneficial in HD. On the other hand, blockade of post-synaptic A(2A)Rs, localized in striatal GABAergic enkephalinergic neurons, could exacerbate the motor dysfunction. To evaluate the function of pre- or post-synaptic A(2A)Rs in HD we used selective antagonists for these receptors in a transgenic rat model of HD. Locomotor activity after systemic administration of the postsynaptic A(2A)R antagonist KW-6002 was used to investigate the function of post-synaptic A(2A)Rs. The role of pre-synaptic A(2A)Rs was instead evaluated by measuring the reduction of the electromyographic response of mastication muscles during electrical stimulation of the orofacial motor cortex after the systemic administration of the presynaptic A(2A)R antagonist SCH-442416. The ability of KW-6002 to produce locomotor activation was lost at 6 and 12 month-old of age in heterozygous and homozygous transgenic rats, but not in wild-type littermates. Nevertheless, no significant changes were observed up to 12 months of age in the potency of SCH-442416 to decrease the electromyographic response after cortical electrical stimulation. These results agree with a selective impairment of the striatal GABAergic enkephalinergic neuronal function during pre-symptomatic stages in HD. Since presynaptic A(2A)R function is not impaired, this receptor could probably be used as a target for the symptomatic treatment of the disease.
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Affiliation(s)
- Marco Orrú
- CNS Receptor-Receptor Interactions Unit, National Institute on Drug Abuse, IRP, NIH, DHHS, Baltimore, MD 21224, USA
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110
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Ena S, de Kerchove d'Exaerde A, Schiffmann SN. Unraveling the differential functions and regulation of striatal neuron sub-populations in motor control, reward, and motivational processes. Front Behav Neurosci 2011; 5:47. [PMID: 21847377 PMCID: PMC3148764 DOI: 10.3389/fnbeh.2011.00047] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 07/18/2011] [Indexed: 12/15/2022] Open
Abstract
The striatum, the major input structure of the basal ganglia, is critically involved in motor control and learning of habits and skills, and is also involved in motivational and reward processes. The dorsal striatum, caudate–putamen, is primarily implicated in motor functions whereas the ventral striatum, the nucleus accumbens, is essential for motivation and drug reinforcement. Severe basal ganglia dysfunction occurs in movement disorders as Parkinson's and Huntington's disease, and in psychiatric disorders such as schizophrenia and drug addiction. The striatum is essentially composed of GABAergic medium-sized spiny neurons (MSNs) that are output neurons giving rise to the so-called direct and indirect pathways and are targets of the cerebral cortex and mesencephalic dopaminergic neurons. Although the involvement of striatal sub-areas in motor control and motivation has been thoroughly characterized, major issues remained concerning the specific and respective functions of the two MSNs sub-populations, D2R-striatopallidal (dopamine D2 receptor-positive) and D1R-striatonigral (dopamine D1 receptor-positive) neurons, as well as their specific regulation. Here, we review recent advances that gave new insight in the understanding of the differential roles of striatopallidal and striatonigral neurons in the basal ganglia circuit. We discuss innovative techniques developed in the last decade which allowed a much precise evaluation of molecular pathways implicated in motivational processes and functional roles of striatopallidal and striatonigral neurons in motor control and in the establishment of reward-associated behavior.
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Affiliation(s)
- Sabrina Ena
- Laboratory of Neurophysiology, School of Medicine, Université Libre de Bruxelles Brussels, Belgium
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111
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Armentero MT, Pinna A, Ferré S, Lanciego JL, Müller CE, Franco R. Past, present and future of A(2A) adenosine receptor antagonists in the therapy of Parkinson's disease. Pharmacol Ther 2011; 132:280-99. [PMID: 21810444 DOI: 10.1016/j.pharmthera.2011.07.004] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 07/07/2011] [Indexed: 12/20/2022]
Abstract
Several selective antagonists for adenosine A(2A) receptors (A(2A)R) are currently under evaluation in clinical trials (phases I to III) to treat Parkinson's disease, and they will probably soon reach the market. The usefulness of these antagonists has been deduced from studies demonstrating functional interactions between dopamine D₂ and adenosine A(2A) receptors in the basal ganglia. At present it is believed that A(2A)R antagonists can be used in combination with the dopamine precursor L-DOPA to minimize the motor symptoms of Parkinson's patients. However, a considerable body of data indicates that in addition to ameliorating motor symptoms, adenosine A(2A)R antagonists may also prevent neurodegeneration. Despite these promising indications, one further issue must be considered in order to develop fully optimized antiparkinsonian drug therapy, namely the existence of (hetero)dimers/oligomers of G protein-coupled receptors, a topic that is currently the focus of intense debate within the scientific community. Dopamine D₂ receptors (D₂Rs) expressed in the striatum are known to form heteromers with A(2A) adenosine receptors. Thus, the development of heteromer-specific A(2A) receptor antagonists represents a promising strategy for the identification of more selective and safer drugs.
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Affiliation(s)
- Marie Therese Armentero
- Laboratory of Functional Neurochemistry, Interdepartmental Research Centre for Parkinson's Disease, IRCCS National Institute of Neurology "C. Mondino", Pavia, Italy
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112
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Souza BR, Tropepe V. The role of dopaminergic signalling during larval zebrafish brain development: a tool for investigating the developmental basis of neuropsychiatric disorders. Rev Neurosci 2011; 22:107-19. [PMID: 21615265 DOI: 10.1515/rns.2011.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Neurodevelopment depends on intrinsic and extrinsic factors that influence the overall pattern of neurogenesis and neural circuit formation, which has a direct impact on behaviour. Defects in dopamine signalling and brain morphology at a relatively early age, and mutations in neurodevelopmental genes are strongly correlated with several neuropsychiatric disorders. This evidence supports the hypothesis of a neurodevelopmental origin of at least some forms of mental illness. Zebrafish (Danio rerio) has emerged as an important vertebrate model system in biomedical research. The ease with which intrinsic and extrinsic factors can be altered during early development, the relatively conserved dopaminergic circuit organisation in the larval brain, and the emergence of simple sensorimotor behaviours very early in development are some of the appealing features that make this organism advantageous for developmental brain and behaviour research. Thus, examining the impact of altered dopamine signalling and disease related genetic aberrations during zebrafish development presents a unique opportunity to holistically analyse the in vivo biochemical, morphological and behavioural significance of altered dopamine signalling during a crucial period of development using a highly tractable vertebrate model organism. Ultimately, this information will shed new light on potential therapeutic targets for the treatment of schizophrenia and perhaps serve as a paradigm for investigating the neurodevelopmental origin of other psychiatric disorders.
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Affiliation(s)
- Bruno Rezende Souza
- Department of Cell and Systems Biology, Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto M5S 3G5, ON, Canada
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113
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Orrú M, Quiroz C, Guitart X, Ferré S. Pharmacological evidence for different populations of postsynaptic adenosine A2A receptors in the rat striatum. Neuropharmacology 2011; 61:967-74. [PMID: 21752341 DOI: 10.1016/j.neuropharm.2011.06.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/13/2011] [Accepted: 06/25/2011] [Indexed: 10/18/2022]
Abstract
Adenosine A(2A) receptors (A(2A)Rs) are highly concentrated in the striatum. Two pharmacological different functional populations of A(2A)Rs have been recently described based on their different affinities for the A(2A)R antagonist SCH-442416. This compound has high affinity for A(2A)Rs not forming heteromers or forming heteromers with adenosine A(1) receptors (A(1)Rs) while showing very low affinity for A(2A)Rs forming heteromers with dopamine D(2) receptors (D(2)Rs). It has been widely described that striatal A(1)R-A(2A)R heteromers are preferentially localized presynaptically in the glutamatergic terminals that contact GABAergic dynorphinergic neurons, and that A(2A)R-D(2)R heteromers are localized postsynaptically in GABAergic enkephalinergic neurons. In the present study we provide evidence suggesting that SCH-442416 also targets postsynaptic A(2A)R not forming heteromers with D(2)R, which are involved in the motor depressant effects induced by D(2)R antagonists. SCH-442416 counteracted motor depression in rats induced by the D(2)R antagonist raclopride at a dose that did not produce motor activation or that blocked motor depression induced by an A(2A)R agonist. Furthermore, we re-evaluated the recently suggested key role of cannabinoid CB(1) receptors (CB(1)Rs) in the effects of A(2A)R antagonists acting at postsynaptic A(2A)Rs. By recording locomotor activity and monitoring striatal glutamate release induced by cortical electrical stimulation in rats after administration of A(2A)R and CB(1)R antagonists, we did not find evidence for any significant role of endocannabinoids in the post- or presynaptic effects of A(2A)R antagonists. The present results further suggest the existence of at least two functionally and pharmacologically different populations of striatal postsynaptic A(2A)Rs.
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Affiliation(s)
- Marco Orrú
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224, USA
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114
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Martini C, Daniele S, Picchetti M, Panighini A, Carlini M, Trincavelli ML, Cesari D, Da Pozzo E, Golia F, Dell'Osso L. A(2A) adenosine receptor binding parameters in platelets from patients affected by pathological gambling. Neuropsychobiology 2011; 63:154-9. [PMID: 21228607 DOI: 10.1159/000321592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 09/27/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS A structural and functional interaction between A(2A) adenosine receptors and D(2) dopamine receptors has been implicated in the pathophysiology of impulse control disorders. The aim of this study was to use platelet membranes to assess A(2A) adenosine receptor affinity and density in patients affected by pathological gambling (PG; which is classified as a specific impulse control disorder) with respect to those of control subjects. METHODS Twelve drug-free PG patients and 12 age- and sex-matched healthy controls were enrolled in the study. PG was diagnosed according to the Structured Clinical Interview for DSM-IV - Patient Version 2.0 and the South Oaks Gambling Screen. A(2A) adenosine receptor binding parameters were evaluated using a [(3)H]ZM(241385) binding assay; affinity and density (B(max)) were determined by means of saturation binding studies with platelet membranes. RESULTS The A(2A) adenosine receptor binding affinity was found to be significantly higher in patients affected by PG than in healthy subjects; in contrast, no significant differences in B(max) were observed between the 2 groups. CONCLUSIONS The elevated A(2A) adenosine receptor binding affinity in platelets from PG patients with respect to control subjects demonstrates for the first time a change in adenosine receptor parameters, and it suggests the involvement of the adenosine system in this pathology. The previously demonstrated hyperactivity of the dopamine system in PG may modulate the A(2A) adenosine receptor, supporting a role for this receptor as a peripheral marker of dopamine dysfunction. Because it is not possible to directly measure the D(2) dopamine receptor in human platelets, these data are particularly relevant to the detection of dopamine dysfunction.
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Affiliation(s)
- Claudia Martini
- Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology, University of Pisa, Pisa, Italy.
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115
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Ferré S, Quiroz C, Orru M, Guitart X, Navarro G, Cortés A, Casadó V, Canela EI, Lluis C, Franco R. Adenosine A(2A) Receptors and A(2A) Receptor Heteromers as Key Players in Striatal Function. Front Neuroanat 2011; 5:36. [PMID: 21731559 PMCID: PMC3118889 DOI: 10.3389/fnana.2011.00036] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 06/08/2011] [Indexed: 11/24/2022] Open
Abstract
A very significant density of adenosine A2A receptors (A2ARs) is present in the striatum, where they are preferentially localized postsynaptically in striatopallidal medium spiny neurons (MSNs). In this localization A2ARs establish reciprocal antagonistic interactions with dopamine D2 receptors (D2Rs). In one type of interaction, A2AR and D2R are forming heteromers and, by means of an allosteric interaction, A2AR counteracts D2R-mediated inhibitory modulation of the effects of NMDA receptor stimulation in the striatopallidal neuron. This interaction is probably mostly responsible for the locomotor depressant and activating effects of A2AR agonist and antagonists, respectively. The second type of interaction involves A2AR and D2R that do not form heteromers and takes place at the level of adenylyl cyclase (AC). Due to a strong tonic effect of endogenous dopamine on striatal D2R, this interaction keeps A2AR from signaling through AC. However, under conditions of dopamine depletion or with blockade of D2R, A2AR-mediated AC activation is unleashed with an increased gene expression and activity of the striatopallidal neuron and with a consequent motor depression. This interaction is probably the main mechanism responsible for the locomotor depression induced by D2R antagonists. Finally, striatal A2ARs are also localized presynaptically, in cortico-striatal glutamatergic terminals that contact the striato-nigral MSN. These presynaptic A2ARs heteromerize with A1 receptors (A1Rs) and their activation facilitates glutamate release. These three different types of A2ARs can be pharmacologically dissected by their ability to bind ligands with different affinity and can therefore provide selective targets for drug development in different basal ganglia disorders.
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Affiliation(s)
- Sergi Ferré
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, U.S. Department of Health and Human Services Baltimore, MD, USA
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116
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Fuxe K, Marcellino D, Borroto-Escuela DO, Frankowska M, Ferraro L, Guidolin D, Ciruela F, Agnati LF. The changing world of G protein-coupled receptors: from monomers to dimers and receptor mosaics with allosteric receptor-receptor interactions. J Recept Signal Transduct Res 2011; 30:272-83. [PMID: 20684666 DOI: 10.3109/10799893.2010.506191] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Based on indications of direct physical interactions between neuropeptide and monoamine receptors in the early 1980s, the term receptor-receptor interactions was introduced and later on the term receptor heteromerization in the early 1990s. Allosteric mechanisms allow an integrative activity to emerge either intramolecularly in G protein-coupled receptor (GPCR) monomers or intermolecularly via receptor-receptor interactions in GPCR homodimers, heterodimers, and receptor mosaics. Stable heteromers of Class A receptors may be formed that involve strong high energy arginine-phosphate electrostatic interactions. These receptor-receptor interactions markedly increase the repertoire of GPCR recognition, signaling and trafficking in which the minimal signaling unit in the GPCR homomers appears to be one receptor and one G protein. GPCR homomers and GPCR assemblies are not isolated but also directly interact with other proteins to form horizontal molecular networks at the plasma membrane.
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Affiliation(s)
- Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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Striatal pre- and postsynaptic profile of adenosine A(2A) receptor antagonists. PLoS One 2011; 6:e16088. [PMID: 21264319 PMCID: PMC3019225 DOI: 10.1371/journal.pone.0016088] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 12/04/2010] [Indexed: 11/19/2022] Open
Abstract
Striatal adenosine A(2A) receptors (A(2A)Rs) are highly expressed in medium spiny neurons (MSNs) of the indirect efferent pathway, where they heteromerize with dopamine D(2) receptors (D(2)Rs). A(2A)Rs are also localized presynaptically in cortico-striatal glutamatergic terminals contacting MSNs of the direct efferent pathway, where they heteromerize with adenosine A(1) receptors (A(1)Rs). It has been hypothesized that postsynaptic A(2A)R antagonists should be useful in Parkinson's disease, while presynaptic A(2A)R antagonists could be beneficial in dyskinetic disorders, such as Huntington's disease, obsessive-compulsive disorders and drug addiction. The aim or this work was to determine whether selective A(2A)R antagonists may be subdivided according to a preferential pre- versus postsynaptic mechanism of action. The potency at blocking the motor output and striatal glutamate release induced by cortical electrical stimulation and the potency at inducing locomotor activation were used as in vivo measures of pre- and postsynaptic activities, respectively. SCH-442416 and KW-6002 showed a significant preferential pre- and postsynaptic profile, respectively, while the other tested compounds (MSX-2, SCH-420814, ZM-241385 and SCH-58261) showed no clear preference. Radioligand-binding experiments were performed in cells expressing A(2A)R-D(2)R and A(1)R-A(2A)R heteromers to determine possible differences in the affinity of these compounds for different A(2A)R heteromers. Heteromerization played a key role in the presynaptic profile of SCH-442416, since it bound with much less affinity to A(2A)R when co-expressed with D(2)R than with A(1)R. KW-6002 showed the best relative affinity for A(2A)R co-expressed with D(2)R than co-expressed with A(1)R, which can at least partially explain the postsynaptic profile of this compound. Also, the in vitro pharmacological profile of MSX-2, SCH-420814, ZM-241385 and SCH-58261 was is in accordance with their mixed pre- and postsynaptic profile. On the basis of their preferential pre- versus postsynaptic actions, SCH-442416 and KW-6002 may be used as lead compounds to obtain more effective antidyskinetic and antiparkinsonian compounds, respectively.
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Effect of the adenosine A2A receptor antagonist MSX-3 on motivational disruptions of maternal behavior induced by dopamine antagonism in the early postpartum rat. Psychopharmacology (Berl) 2011; 213:69-79. [PMID: 20848086 PMCID: PMC3077895 DOI: 10.1007/s00213-010-2015-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 08/29/2010] [Indexed: 10/19/2022]
Abstract
RATIONALE Mesolimbic dopamine (DA), particularly in the nucleus accumbens, importantly regulates activational aspects of maternal responsiveness. DA antagonism and accumbens DA depletions interfere with early postpartum maternal motivation by selectively affecting most forms of active maternal behaviors, while leaving nursing behavior relatively intact. Considerable evidence indicates that there is a functional interaction between DA D2 and adenosine A(2A) receptors in striatal areas, including the nucleus accumbens. OBJECTIVE This study was conducted to determine if adenosine A(2A) receptor antagonism could reverse the effects of DA receptor antagonism on early postpartum maternal behavior. METHODS The adenosine A(2A) receptor antagonist MSX-3 (0.25-2.0 mg/kg, IP) was investigated for its ability to reverse the effects of the DA D2 receptor antagonist haloperidol (0.1 mg/kg, IP) on the maternal behavior of early postpartum female rats. RESULTS Haloperidol severely impaired the expression of active maternal components, including retrieval and grouping the pups at the nest site, pup licking, and nest building. Co-administration of MSX-3 (0.25-2.0 mg/kg, IP) with haloperidol produced a dose-related attenuation of the haloperidol-induced behavioral deficits in early postpartum females. Doses of MSX-3 that effectively reversed the effects of haloperidol (0.5, 1.0 mg/kg), when administered in the absence of haloperidol, did not affect maternal responding or locomotor activity. CONCLUSIONS Adenosine and DA systems interact to regulate early postpartum maternal responsiveness. This research may potentially contribute to the development of strategies for treatments of psychiatric disorders during the postpartum period, with particular emphasis in maintaining or restoring the mother-infant relationship.
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Chen JF, Chern Y. Impacts of methylxanthines and adenosine receptors on neurodegeneration: human and experimental studies. Handb Exp Pharmacol 2011:267-310. [PMID: 20859800 DOI: 10.1007/978-3-642-13443-2_10] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Neurodegenerative disorders are some of the most feared illnesses in modern society, with no effective treatments to slow or halt this neurodegeneration. Several decades after the earliest attempt to treat Parkinson's disease using caffeine, tremendous amounts of information regarding the potential beneficial effect of caffeine as well as adenosine drugs on major neurodegenerative disorders have accumulated. In the first part of this review, we provide general background on the adenosine receptor signaling systems by which caffeine and methylxanthine modulate brain activity and their role in relationship to the development and treatment of neurodegenerative disorders. The demonstration of close interaction between adenosine receptor and other G protein coupled receptors and accessory proteins might offer distinct pharmacological properties from adenosine receptor monomers. This is followed by an outline of the major mechanism underlying neuroprotection against neurodegeneration offered by caffeine and adenosine receptor agents. In the second part, we discuss the current understanding of caffeine/methylxantheine and its major target adenosine receptors in development of individual neurodegenerative disorders, including stroke, traumatic brain injury Alzheimer's disease, Parkinson's disease, Huntington's disease and multiple sclerosis. The exciting findings to date include the specific in vivo functions of adenosine receptors revealed by genetic mouse models, the demonstration of a broad spectrum of neuroprotection by chronic treatment of caffeine and adenosine receptor ligands in animal models of neurodegenerative disorders, the encouraging development of several A(2A) receptor selective antagonists which are now in advanced clinical phase III trials for Parkinson's disease. Importantly, increasing body of the human and experimental studies reveals encouraging evidence that regular human consumption of caffeine in fact may have several beneficial effects on neurodegenerative disorders, from motor stimulation to cognitive enhancement to potential neuroprotection. Thus, with regard to neurodegenerative disorders, these potential benefits of methylxanthines, caffeine in particular, strongly argue against the common practice by clinicians to discourage regular human consumption of caffeine in aging populations.
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Affiliation(s)
- Jiang-Fan Chen
- Department of Neurology, Boston University School of Medicine, Boston, MA, USA.
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Ferré S, Lluís C, Justinova Z, Quiroz C, Orru M, Navarro G, Canela EI, Franco R, Goldberg SR. Adenosine-cannabinoid receptor interactions. Implications for striatal function. Br J Pharmacol 2010; 160:443-53. [PMID: 20590556 DOI: 10.1111/j.1476-5381.2010.00723.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Adenosine and endocannabinoids are very ubiquitous non-classical neurotransmitters that exert a modulatory role on the transmission of other more 'classical' neurotransmitters. In this review we will focus on their common role as modulators of dopamine and glutamate neurotransmission in the striatum, the main input structure of the basal ganglia. We will pay particular attention to the role of adenosine A(2A) receptors and cannabinoid CB(1) receptors. Experimental results suggest that presynaptic CB(1) receptors interacting with A(2A) receptors in cortico-striatal glutamatergic terminals that make synaptic contact with dynorphinergic medium-sized spiny neurons (MSNs) are involved in the motor-depressant and addictive effects of cannabinoids. On the other hand, postsynaptic CB(1) receptors interacting with A(2A) and D(2) receptors in the dendritic spines of enkephalinergic MSNs and postsynaptic CB(1) receptors in the dendritic spines of dynorphinergic MSN are probably involved in the cataleptogenic effects of cannabinoids. These receptor interactions most probably depend on the existence of a variety of heteromers of A(2A), CB(1) and D(2) receptors in different elements of striatal spine modules. Drugs selective for the different striatal A(2A) and CB(1) receptor heteromers could be used for the treatment of neuropsychiatric disorders and drug addiction and they could provide effective drugs with fewer side effects than currently used drugs.
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Affiliation(s)
- Sergi Ferré
- National Institute on Drug Abuse, IRP, NIH, DHHS, Baltimore, MD 21224, USA.
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Trincavelli ML, Cuboni S, Catena Dell'osso M, Maggio R, Klotz KN, Novi F, Panighini A, Daniele S, Martini C. Receptor crosstalk: haloperidol treatment enhances A(2A) adenosine receptor functioning in a transfected cell model. Purinergic Signal 2010; 6:373-81. [PMID: 21437008 DOI: 10.1007/s11302-010-9201-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 09/30/2010] [Indexed: 11/25/2022] Open
Abstract
UNLABELLED A(2A) adenosine receptors are considered an excellent target for drug development in several neurological and psychiatric disorders. It is noteworthy that the responses evoked by A(2A) adenosine receptors are regulated by D(2) dopamine receptor ligands. These two receptors are co-expressed at the level of the basal ganglia and interact to form functional heterodimers. In this context, possible changes in A(2A) adenosine receptor functional responses caused by the chronic blockade/activation of D(2) dopamine receptors should be considered to optimise the therapeutic effectiveness of dopaminergic agents and to reduce any possible side effects. In the present paper, we investigated the regulation of A(2A) adenosine receptors induced by antipsychotic drugs, commonly acting as D(2) dopamine receptor antagonists, in a cellular model co-expressing both A(2A) and D(2) receptors. Our data suggest that the treatment of cells with the classical antipsychotic haloperidol increased both the affinity and responsiveness of the A(2A) receptor and also affected the degree of A(2A)-D(2) receptor heterodimerisation. In contrast, an atypical antipsychotic, clozapine, had no effect on A(2A) adenosine receptor parameters, suggesting that the two classes of drugs have different effects on adenosine-dopamine receptor interaction. Modifications to A(2A) adenosine receptors may play a significant role in determining cerebral adenosine effects during the chronic administration of antipsychotics in psychiatric diseases and may account for the efficacy of A(2A) adenosine receptor ligands in pathologies associated with dopaminergic system dysfunction. ELECTRONIC SUPPLEMENTARY MATERIAL The online version of this article (doi:10.1007/s11302-010-9201-z) contains supplementary material, which is available to authorized users.
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Jagannathan K, Calhoun VD, Gelernter J, Stevens MC, Liu J, Bolognani F, Windemuth A, Ruaño G, Assaf M, Pearlson GD. Genetic associations of brain structural networks in schizophrenia: a preliminary study. Biol Psychiatry 2010; 68:657-66. [PMID: 20691427 PMCID: PMC2990476 DOI: 10.1016/j.biopsych.2010.06.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 05/25/2010] [Accepted: 06/03/2010] [Indexed: 11/29/2022]
Abstract
BACKGROUND Schizophrenia is a complex genetic disorder, with multiple putative risk genes and many reports of reduced cortical gray matter. Identifying the genetic loci contributing to these structural alterations in schizophrenia (and likely also to normal structural gray matter patterns) could aid understanding of schizophrenia's pathophysiology. We used structural parameters as potential intermediate illness markers to investigate genomic factors derived from single nucleotide polymorphism (SNP) arrays. METHOD We used research quality structural magnetic resonance imaging (sMRI) scans from European American subjects including 33 healthy control subjects and 18 schizophrenia patients. All subjects were genotyped for 367 SNPs. Linked sMRI and genetic (SNP) components were extracted to reveal relationships between brain structure and SNPs, using parallel independent component analysis, a novel multivariate approach that operates effectively in small sample sizes. RESULTS We identified an sMRI component that significantly correlated with a genetic component (r = -.536, p < .00005); components also distinguished groups. In the sMRI component, schizophrenia gray matter deficits were in brain regions consistently implicated in previous reports, including frontal and temporal lobes and thalamus (p < .01). These deficits were related to SNPs from 16 genes, several previously associated with schizophrenia risk and/or involved in normal central nervous system development, including AKT, PI3K, SLC6A4, DRD2, CHRM2, and ADORA2A. CONCLUSIONS Despite the small sample size, this novel analysis method identified an sMRI component including brain areas previously reported to be abnormal in schizophrenia and an associated genetic component containing several putative schizophrenia risk genes. Thus, we identified multiple genes potentially underlying specific structural brain abnormalities in schizophrenia.
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Affiliation(s)
- Kanchana Jagannathan
- Olin Neuropsychiatry Research Center, Institute of Living/Hartford Hospital, Hartford, Connecticut 06106, USA.
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Modulation of the striato-pallidal pathway by adenosine A2a receptors depends on dopaminergic striatal input. Brain Res 2010; 1349:137-42. [DOI: 10.1016/j.brainres.2010.06.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 05/04/2010] [Accepted: 06/15/2010] [Indexed: 11/20/2022]
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Lusardi TA. Adenosine neuromodulation and traumatic brain injury. Curr Neuropharmacol 2010; 7:228-37. [PMID: 20190964 PMCID: PMC2769006 DOI: 10.2174/157015909789152137] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 05/18/2009] [Accepted: 05/20/2009] [Indexed: 12/17/2022] Open
Abstract
Adenosine is a ubiquitous signaling molecule, with widespread activity across all organ systems. There is evidence that adenosine regulation is a significant factor in traumatic brain injury (TBI) onset, recovery, and outcome, and a growing body of experimental work examining the therapeutic potential of adenosine neuromodulation in the treatment of TBI. In the central nervous system (CNS), adenosine (dys)regulation has been demonstrated following TBI, and correlated to several TBI pathologies, including impaired cerebral hemodynamics, anaerobic metabolism, and inflammation. In addition to acute pathologies, adenosine function has been implicated in TBI comorbidities, such as cognitive deficits, psychiatric function, and post-traumatic epilepsy. This review presents studies in TBI as well as adenosine-related mechanisms in co-morbidities of and unfavorable outcomes resulting from TBI. While the exact role of the adenosine system following TBI remains unclear, there is increasing evidence that a thorough understanding of adenosine signaling will be critical to the development of diagnostic and therapeutic tools for the treatment of TBI.
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Affiliation(s)
- T A Lusardi
- R. S. Dow Neurobiology Laboratory, Portland OR, USA.
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125
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Navarro G, Ferré S, Cordomi A, Moreno E, Mallol J, Casadó V, Cortés A, Hoffmann H, Ortiz J, Canela EI, Lluís C, Pardo L, Franco R, Woods AS. Interactions between intracellular domains as key determinants of the quaternary structure and function of receptor heteromers. J Biol Chem 2010; 285:27346-27359. [PMID: 20562103 DOI: 10.1074/jbc.m110.115634] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptor (GPCR) heteromers are macromolecular complexes with unique functional properties different from those of its individual protomers. Little is known about what determines the quaternary structure of GPCR heteromers resulting in their unique functional properties. In this study, using resonance energy transfer techniques in experiments with mutated receptors, we provide for the first time clear evidence for a key role of intracellular domains in the determination of the quaternary structure of GPCR heteromers between adenosine A(2A), cannabinoid CB(1), and dopamine D(2) receptors. In these interactions, arginine-rich epitopes form salt bridges with phosphorylated serine or threonine residues from CK1/2 consensus sites. Each receptor (A(2A), CB(1), and D(2)) was found to include two evolutionarily conserved intracellular domains to establish selective electrostatic interactions with intracellular domains of the other two receptors, indicating that these particular electrostatic interactions constitute a general mechanism for receptor heteromerization. Mutation experiments indicated that the interactions of the intracellular domains of the CB(1) receptor with A(2A) and D(2) receptors are fundamental for the correct formation of the quaternary structure needed for the function (MAPK signaling) of the A(2A)-CB(1)-D(2) receptor heteromers. Analysis of MAPK signaling in striatal slices of CB(1) receptor KO mice and wild-type littermates supported the existence of A(1)-CB(1)-D(2) receptor heteromer in the brain. These findings allowed us to propose the first molecular model of the quaternary structure of a receptor heteromultimer.
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Affiliation(s)
- Gemma Navarro
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Sergi Ferré
- Intramural Research Program, National Institute on Drug Abuse, Department of Health and Human Services, Baltimore, Maryland 21224
| | - Arnau Cordomi
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Universitat Autónoma de Barcelona, 08193 Bellaterra, Spain
| | - Estefania Moreno
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Josefa Mallol
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Antoni Cortés
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Hanne Hoffmann
- Neuroscience Institute and Department of Biochemistry and Molecular Biology, Facultat de Medicina, Universitat Autónoma de Barcelona, 08193 Bellaterra, Spain
| | - Jordi Ortiz
- Neuroscience Institute and Department of Biochemistry and Molecular Biology, Facultat de Medicina, Universitat Autónoma de Barcelona, 08193 Bellaterra, Spain
| | - Enric I Canela
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Carme Lluís
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Leonardo Pardo
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Universitat Autónoma de Barcelona, 08193 Bellaterra, Spain
| | - Rafael Franco
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Médica Aplicada, Universidad de Navarra, 31008 Pamplona, Spain
| | - Amina S Woods
- Intramural Research Program, National Institute on Drug Abuse, Department of Health and Human Services, Baltimore, Maryland 21224.
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John D Salamone, Merce Correa, Andrew M Farrar, Eric J Nunes. Role of dopamine–adenosine interactions in the brain circuitry regulating effort-related decision making: insights into pathological aspects of motivation. FUTURE NEUROLOGY 2010. [DOI: 10.2217/fnl.10.19] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Brain dopamine, particularly in the nucleus accumbens, has been implicated in activational aspects of motivation and effort-related processes. Accumbens dopamine depletions reduce the tendency of rats to work for food, and alter effort-related decision making, but leave aspects of food motivation such as appetite intact. Recent evidence indicates that the purine neuromodulator adenosine, largely through actions on adenosine A2A receptors, also participates in regulating effort-related processes. Adenosine A2A antagonists can reverse the effects of dopamine D2 antagonists on effort-related choice, and intra-accumbens injections of adenosine A2A agonists produce effects that are similar to those induced by accumbens dopamine depletion or antagonism. These studies have implications for the understanding and treatment of energy-related disorders such as anergia and fatigue in psychiatry and neurology.
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Quiroz C, Pearson V, Gulyani S, Allen R, Earley C, Ferré S. Up-regulation of striatal adenosine A(2A) receptors with iron deficiency in rats: effects on locomotion and cortico-striatal neurotransmission. Exp Neurol 2010; 224:292-8. [PMID: 20385128 DOI: 10.1016/j.expneurol.2010.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 03/27/2010] [Accepted: 04/03/2010] [Indexed: 11/30/2022]
Abstract
Brain iron deficiency leads to altered dopaminergic function in experimental animals, which can provide a mechanistic explanation for iron deficiency-related human sensory-motor disorders, such as Restless Legs Syndrome (RLS). However, mechanisms linking both conditions have not been determined. Considering the strong modulation exerted by adenosine on dopamine signaling, one connection could involve changes in adenosine receptor expression or function. In the striatum, presynaptic A(2A) receptors are localized in glutamatergic terminals contacting GABAergic dynorphinergic neurons and their function can be analyzed by the ability of A(2A) receptor antagonists to block the motor output induced by cortical electrical stimulation. Postsynaptic A(2A) receptors are localized in the dendritic field of GABAergic enkephalinergic neurons and their function can be analyzed by studying the ability of A(2A) receptor antagonists to produce locomotor activity and to counteract striatal ERK1/2 phosphorylation induced by cortical electrical stimulation. Increased density of striatal A(2A) receptors was found in rats fed during 3 weeks with an iron-deficient diet during the post-weaning period. In iron-deficient rats, the selective A(2A) receptor antagonist MSX-3, at doses of 1 and 3 mg/kg, was more effective at blocking motor output induced by cortical electrical stimulation (presynaptic A(2A) receptor-mediated effect) and at enhancing locomotor activation and blocking striatal ERK phosphorylation induced by cortical electrical stimulation (postsynaptic A(2A) receptor-mediated effects). These results indicate that brain iron deficiency induces a functional up-regulation of both striatal pre- and postsynaptic A(2A) receptor, which could be involved in sensory-motor disorders associated with iron deficiency such as RLS.
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Affiliation(s)
- César Quiroz
- National Institute on Drug Abuse, IRP, NIH, DHHS, Baltimore, MD 21224, USA.
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Thibault D, Kortleven C, Fasano C, Dal Bo G, Trudeau LÉ. Découvertes récentes sur la fonction et la plasticité des voies dopaminergiques du cerveau. Med Sci (Paris) 2010; 26:165-70. [DOI: 10.1051/medsci/2010262165] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Ferrante A, Martire A, Armida M, Chiodi V, Pézzola A, Potenza RL, Domenici MR, Popoli P. Influence of CGS 21680, a selective adenosine A(2A) receptor agonist, on NMDA receptor function and expression in the brain of Huntington's disease mice. Brain Res 2010; 1323:184-91. [PMID: 20138162 DOI: 10.1016/j.brainres.2010.01.080] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 01/27/2010] [Accepted: 01/28/2010] [Indexed: 10/19/2022]
Abstract
The effect of chronic treatment with the selective adenosine A(2A) receptor agonist CGS 21680 on N-Methyl-d-Aspartate (NMDA) receptor function and expression has been studied in the striatum and cortex of R6/2 mice, a genetic mouse model of Huntington's disease (HD). Starting from 8weeks of age, R6/2 and wild type (WT) mice were treated daily with CGS 21680 (0.5mg/kg i.p.) for 3weeks and the expression levels of NMDA receptor subunits were then evaluated. In addition, to study CGS 21680-induced changes in NMDA receptor function, NMDA-induced toxicity in corticostriatal slices from both R6/2 and WT mice was investigated. We found that CGS 21680 increased NR2A subunit expression and the NR2A/NR2B ratio in the cortex of R6/2 mice, having no effect in WT mice. In the striatum, CGS 21680 reduced NR1 expression in both R6/2 and WT mice while the effect on NR2A and NR2/NR2B expression was genotype-dependent, reducing and increasing their expression in WT and R6/2 mice, respectively. On the contrary, NMDA-induced toxicity in corticostriatal slices was not modified by the treatment in WT or HD mice. These results demonstrate that in vivo activation of A(2A) receptors modulates the subunit composition of NMDA receptors in the brain of HD mice.
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Affiliation(s)
- Antonella Ferrante
- Department of Therapeutic Research and Medicine Evaluation, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161, Rome, Italy
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Ferré S, Navarro G, Casadó V, Cortés A, Mallol J, Canela EI, Lluís C, Franco R. G protein-coupled receptor heteromers as new targets for drug development. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 91:41-52. [PMID: 20691958 DOI: 10.1016/s1877-1173(10)91002-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We now have a significant amount of experimental evidence that indicates that G protein-coupled receptor (GPCR) oligomerization, including homo- and heteromerization, is a general phenomenon. Receptor heteromers possess unique biochemical characteristics that are demonstrably different from those of its individual units. These properties include allosteric modulation(s) between units, changes in ligand recognition, G protein-coupling and trafficking. The discovery of GPCR oligomers have been related to the parallel discovery and application of a variety of resonance energy transfer (RET) techniques, such as bioluminescence, fluorescence and sequential RET (BRET, FRET and SRET, respectively), time-resolved FRET (T-FRET) and fluorescence recovery after photobleaching (FRAP) microscopy. However, RET techniques are difficult to implement in native tissues. For receptor heteromers, indirect approaches, such as the determination of a unique biochemical characteristic ("biochemical fingerprint"), permit their identification in native tissues and their use as targets for drug development. Dopamine and opioid receptor heteromers are the focus of intense research which is related to the possible multiple applications of their putative ligands in pathological conditions, which include basal ganglia disorders, schizophrenia and drug addiction.
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Affiliation(s)
- Sergi Ferré
- National Institute on Drug Abuse, IRP, NIH, DHHS, Baltimore, Maryland, USA
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Genetic deletion of A2A adenosine receptors in the striatum selectively impairs habit formation. J Neurosci 2009; 29:15100-3. [PMID: 19955361 DOI: 10.1523/jneurosci.4215-09.2009] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A(2A) receptors are a major class of G-protein-coupled receptors for adenosine. Highly expressed in the striatum, on the projection neurons giving rise to the striatopallidal or "indirect" pathway, they have been implicated in sleep, addiction, and other processes, yet their role in the control of striatal circuits and behavior remains unclear. Using established assays from the instrumental learning paradigm, we showed that mice with striatum-specific deletion of A(2A) receptors were selectively impaired in habit formation. After training that generated habitual lever pressing in wild-type controls, the performance of striatum-specific A(2A) knock-out mice remained goal directed, being highly sensitive to outcome devaluation and reversal of the action-outcome contingency. These data demonstrate a critical role for A(2A) receptors on striatopallidal medium spiny projection neurons in shaping behavior and decision making, providing the first instance of a selective alteration in instrumental learning after striatum-specific genetic manipulations.
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132
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Quiroz C, Luján R, Uchigashima M, Simoes AP, Lerner TN, Borycz J, Kachroo A, Canas PM, Orru M, Schwarzschild MA, Rosin DL, Kreitzer AC, Cunha RA, Watanabe M, Ferré S. Key modulatory role of presynaptic adenosine A2A receptors in cortical neurotransmission to the striatal direct pathway. ScientificWorldJournal 2009; 9:1321-44. [PMID: 19936569 PMCID: PMC2871285 DOI: 10.1100/tsw.2009.143] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Basal ganglia processing results from a balanced activation of direct and indirect striatal efferent pathways, which are controlled by dopamine D1 and D2 receptors, respectively. Adenosine A2A receptors are considered novel antiparkinsonian targets, based on their selective postsynaptic localization in the indirect pathway, where they modulate D2 receptor function. The present study provides evidence for the existence of an additional, functionally significant, segregation of A2A receptors at the presynaptic level. Using integrated anatomical, electrophysiological, and biochemical approaches, we demonstrate that presynaptic A2A receptors are preferentially localized in cortical glutamatergic terminals that contact striatal neurons of the direct pathway, where they exert a selective modulation of corticostriatal neurotransmission. Presynaptic striatal A2A receptors could provide a new target for the treatment of neuropsychiatric disorders.
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Affiliation(s)
- César Quiroz
- National Institute on Drug Abuse, IRP, NIH, DHHS, Baltimore, MD, USA
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133
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Ferré S, Woods AS, Navarro G, Aymerich M, Lluís C, Franco R. Calcium-mediated modulation of the quaternary structure and function of adenosine A2A-dopamine D2 receptor heteromers. Curr Opin Pharmacol 2009; 10:67-72. [PMID: 19896897 DOI: 10.1016/j.coph.2009.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 10/05/2009] [Accepted: 10/05/2009] [Indexed: 10/20/2022]
Abstract
The adenosine A(2A)-dopamine D(2) receptor heteromer is one of the most studied receptor heteromers. It has important implications for basal ganglia function and pathology. Recent studies using Bioluminescence and Sequential Resonance Energy Transfer techniques shed light on the role of Ca(2+) in the modulation of the quaternary structure of the A(2A)-D(2) receptor heteromer, which was found to depend on the binding of calmodulin (CaM) to the carboxy-terminus of the A(2A) receptor in the A(2A)-D(2) receptor heteromer. Importantly, the changes in quaternary structure correlate with changes in function. A Ca(2+)/CaM-dependent modulation of MAPK signaling upon agonist treatment could be observed in cells expressing A(2A)-D(2) receptor heteromers. These studies provide a first example of a Ca(2+)-mediated modulation of the quaternary structure and function of a receptor heteromer.
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Affiliation(s)
- Sergi Ferré
- National Institute on Drug Abuse, IRP, NIH, DHHS, Baltimore, MD 21224, USA.
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134
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Bird MK, Lawrence AJ. The promiscuous mGlu5 receptor--a range of partners for therapeutic possibilities? Trends Pharmacol Sci 2009; 30:617-23. [PMID: 19892412 DOI: 10.1016/j.tips.2009.09.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 09/23/2009] [Accepted: 09/23/2009] [Indexed: 01/20/2023]
Abstract
The issue of non-specific effects for potential therapeutics is particularly salient in neurological/psychiatric disorders, where adverse drug reactions could impair critical brain functions. The issue of specificity is not limited to candidate molecules, as receptor targets themselves often influence physiological as well as pathological outcomes. Metabotropic glutamate receptor 5 (mGlu5) is an example of a "promiscuous" receptor target that has been implicated in addiction, but also many other processes. However, if receptor modulation could be restricted to specific pathways/brain regions, mGlu5 may still prove to be a viable therapeutic target for various indications. Using this premise, a number of possible methods to refine drug development strategy are discussed, including exploiting specific interactions of mGlu5 with other receptors to narrow the influence of pharmacological agents, and also the use of RNA interference targeted to specific cells/regions of the brain.
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Affiliation(s)
- Michael K Bird
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Victoria, 3010, Australia
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135
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Azdad K, Chàvez M, Bischop PD, Wetzelaer P, Marescau B, De Deyn PP, Gall D, Schiffmann SN. Homeostatic plasticity of striatal neurons intrinsic excitability following dopamine depletion. PLoS One 2009; 4:e6908. [PMID: 19730738 PMCID: PMC2733153 DOI: 10.1371/journal.pone.0006908] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 08/05/2009] [Indexed: 11/18/2022] Open
Abstract
The striatum is the major input structure of basal ganglia and is involved in adaptive control of behaviour through the selection of relevant informations. Dopaminergic neurons that innervate striatum die in Parkinson disease, leading to inefficient adaptive behaviour. Neuronal activity of striatal medium spiny neurons (MSN) is modulated by dopamine receptors. Although dopamine signalling had received substantial attention, consequences of dopamine depletion on MSN intrinsic excitability remain unclear. Here we show, by performing perforated patch clamp recordings on brain slices, that dopamine depletion leads to an increase in MSN intrinsic excitability through the decrease of an inactivating A-type potassium current, I(A). Despite the large decrease in their excitatory synaptic inputs determined by the decreased dendritic spines density and the increase in minimal current to evoke the first EPSP, this increase in intrinsic excitability resulted in an enhanced responsiveness to their remaining synapses, allowing them to fire similarly or more efficiently following input stimulation than in control condition. Therefore, this increase in intrinsic excitability through the regulation of I(A) represents a form of homeostatic plasticity allowing neurons to compensate for perturbations in synaptic transmission and to promote stability in firing. The present observations show that this homeostatic ability to maintain firing rates within functional range also occurs in pathological conditions, allowing stabilizing neural computation within affected neuronal networks.
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Affiliation(s)
- Karima Azdad
- Laboratory of Neurophysiology, University of Brussels (ULB), Brussels, Belgium
- European Graduate School of Neuroscience (EURON), Maastricht, The Netherlands
- * E-mail: (KA); (SNS)
| | - Marcelo Chàvez
- Laboratory of Neurophysiology, University of Brussels (ULB), Brussels, Belgium
- European Graduate School of Neuroscience (EURON), Maastricht, The Netherlands
| | - Patrick Don Bischop
- Laboratory of Neurophysiology, University of Brussels (ULB), Brussels, Belgium
- European Graduate School of Neuroscience (EURON), Maastricht, The Netherlands
| | - Pim Wetzelaer
- Laboratory of Neurophysiology, University of Brussels (ULB), Brussels, Belgium
- European Graduate School of Neuroscience (EURON), Maastricht, The Netherlands
| | - Bart Marescau
- Department of Biomedical Sciences, Laboratory of Neurochemistry and Behaviour, Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium
| | - Peter Paul De Deyn
- Department of Biomedical Sciences, Laboratory of Neurochemistry and Behaviour, Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium
| | - David Gall
- Laboratory of Neurophysiology, University of Brussels (ULB), Brussels, Belgium
- European Graduate School of Neuroscience (EURON), Maastricht, The Netherlands
| | - Serge N. Schiffmann
- Laboratory of Neurophysiology, University of Brussels (ULB), Brussels, Belgium
- European Graduate School of Neuroscience (EURON), Maastricht, The Netherlands
- * E-mail: (KA); (SNS)
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136
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Franco R. G-protein-coupled receptor heteromers or how neurons can display differently flavoured patterns in response to the same neurotransmitter. Br J Pharmacol 2009; 158:23-31. [PMID: 19422387 DOI: 10.1111/j.1476-5381.2009.00181.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
It is becoming accepted that G-protein-coupled receptors (GPCRs) arrange in the neuronal membrane into homo- and hetero-oligomers and, therefore, these complexes mediate neurotransmission. New models are then needed to understand GPCR operation and predict the consequences of GPCR homo- or hetero-oligomerization. Although there is not any unifying theory addressing how hetero-oligomerization occurs, recent models have been devised to understand the thermodynamics of binding of neurotransmitters to GPCRs and the allosteric protomer-protomer interactions involved in neurotransmitter-mediated activation of GPCRs. Although a model to predict how signalling is produced via homo- or hetero-oligomerization is lacking, functional data show that receptor oligomers exist to produce a variety of effects in neurons in response to a single neurotransmitter.
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Affiliation(s)
- Rafael Franco
- Molecular Neurobiology Unit, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Departament de Bioquímica i Biología Molecular, School of Biology, University of Barcelona, Spain.
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