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Nguyen H, Glaaser IW, Slesinger PA. Direct modulation of G protein-gated inwardly rectifying potassium (GIRK) channels. Front Physiol 2024; 15:1386645. [PMID: 38903913 PMCID: PMC11187414 DOI: 10.3389/fphys.2024.1386645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/08/2024] [Indexed: 06/22/2024] Open
Abstract
Ion channels play a pivotal role in regulating cellular excitability and signal transduction processes. Among the various ion channels, G-protein-coupled inwardly rectifying potassium (GIRK) channels serve as key mediators of neurotransmission and cellular responses to extracellular signals. GIRK channels are members of the larger family of inwardly-rectifying potassium (Kir) channels. Typically, GIRK channels are activated via the direct binding of G-protein βγ subunits upon the activation of G-protein-coupled receptors (GPCRs). GIRK channel activation requires the presence of the lipid signaling molecule, phosphatidylinositol 4,5-bisphosphate (PIP2). GIRK channels are also modulated by endogenous proteins and other molecules, including RGS proteins, cholesterol, and SNX27 as well as exogenous compounds, such as alcohol. In the last decade or so, several groups have developed novel drugs and small molecules, such as ML297, GAT1508 and GiGA1, that activate GIRK channels in a G-protein independent manner. Here, we aim to provide a comprehensive overview focusing on the direct modulation of GIRK channels by G-proteins, PIP2, cholesterol, and novel modulatory compounds. These studies offer valuable insights into the underlying molecular mechanisms of channel function, and have potential implications for both basic research and therapeutic development.
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Affiliation(s)
| | | | - Paul A. Slesinger
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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2
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Clark PJ, Brodnik ZD, España RA. Chemogenetic Signaling in Space and Time: Considerations for Designing Neuroscience Experiments Using DREADDs. Neuroscientist 2024; 30:328-346. [PMID: 36408535 DOI: 10.1177/10738584221134587] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
The use of designer receptors exclusively activated by designer drugs (DREADDs) has led to significant advances in our understanding of the neural circuits that govern behavior. By allowing selective control over cellular activity and signaling, DREADDs have become an integral tool for defining the pathways and cellular phenotypes that regulate sleep, pain, motor activity, goal-directed behaviors, and a variety of other processes. In this review, we provide a brief overview of DREADDs and discuss notable discoveries in the neurosciences with an emphasis on circuit mechanisms. We then highlight methodological approaches to achieve pathway specific activation of DREADDs. Finally, we discuss spatial and temporal constraints of DREADDs signaling and how these features can be incorporated into experimental designs to precisely dissect circuits of interest.
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Affiliation(s)
- Philip J Clark
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
| | - Zachary D Brodnik
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
| | - Rodrigo A España
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
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3
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Zhang AQ, Ralph MR, Stinchcombe AR. A mathematical model for the role of dopamine-D2 self-regulation in the production of ultradian rhythms. PLoS Comput Biol 2024; 20:e1012082. [PMID: 38701077 PMCID: PMC11095719 DOI: 10.1371/journal.pcbi.1012082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 05/15/2024] [Accepted: 04/17/2024] [Indexed: 05/05/2024] Open
Abstract
Many self-motivated and goal-directed behaviours display highly flexible, approximately 4 hour ultradian (shorter than a day) oscillations. Despite lacking direct correspondence to physical cycles in the environment, these ultradian rhythms may be involved in optimizing functional interactions with the environment and reflect intrinsic neural dynamics. Current evidence supports a role of mesostriatal dopamine (DA) in the expression and propagation of ultradian rhythmicity, however, the biochemical processes underpinning these oscillations remain to be identified. Here, we use a mathematical model to investigate D2 autoreceptor-dependent DA self-regulation as the source of ultradian behavioural rhythms. DA concentration at the midbrain-striatal synapses is governed through a dual-negative feedback-loop structure, which naturally gives rise to rhythmicity. This model shows the propensity of striatal DA to produce an ultradian oscillation characterized by a flexible period that is highly sensitive to parameter variations. Circadian (approximately 24 hour) regulation consolidates the ultradian oscillations and alters their response to the phase-dependent, rapid-resetting effect of a transient excitatory stimulus. Within a circadian framework, the ultradian rhythm orchestrates behavioural activity and enhances responsiveness to an external stimulus. This suggests a role for the circadian-ultradian timekeeping hierarchy in governing organized behaviour and shaping daily experience through coordinating the motivation to engage in recurring, albeit not highly predictable events, such as social interactions.
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Affiliation(s)
- An Qi Zhang
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Martin R. Ralph
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
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4
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Zald DH. The influence of dopamine autoreceptors on temperament and addiction risk. Neurosci Biobehav Rev 2023; 155:105456. [PMID: 37926241 DOI: 10.1016/j.neubiorev.2023.105456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/22/2023] [Accepted: 10/31/2023] [Indexed: 11/07/2023]
Abstract
As a major regulator of dopamine (DA), DA autoreceptors (DAARs) exert substantial influence over DA-mediated behaviors. This paper reviews the physiological and behavioral impact of DAARs. Individual differences in DAAR functioning influences temperamental traits such as novelty responsivity and impulsivity, both of which are associated with vulnerability to addictive behavior in animal models and a broad array of externalizing behaviors in humans. DAARs additionally impact the response to psychostimulants and other drugs of abuse. Human PET studies of D2-like receptors in the midbrain provide evidence for parallels to the animal literature. These data lead to the proposal that weak DAAR regulation is a risk factor for addiction and externalizing problems. The review highlights the potential to build translational models of the functional role of DAARs in behavior. It also draws attention to key limitations in the current literature that would need to be addressed to further advance a weak DAAR regulation model of addiction and externalizing risk.
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Affiliation(s)
- David H Zald
- Center for Advanced Human Brain Imaging and Department of Psychiatry, Rutgers University, Piscataway, NJ, USA.
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5
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Støier JF, Konomi-Pilkati A, Apuschkin M, Herborg F, Gether U. Amphetamine-induced reverse transport of dopamine does not require cytosolic Ca 2. J Biol Chem 2023; 299:105063. [PMID: 37468107 PMCID: PMC10448275 DOI: 10.1016/j.jbc.2023.105063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023] Open
Abstract
Amphetamines (AMPHs) are substrates of the dopamine transporter (DAT) and reverse the direction of dopamine (DA) transport. This has been suggested to depend on activation of Ca2+-dependent pathways, but the mechanism underlying reverse transport via endogenously expressed DAT is still unclear. Here, to enable concurrent visualization by live imaging of extracellular DA dynamics and cytosolic Ca2+ levels, we employ the fluorescent Ca2+ sensor jRGECO1a expressed in cultured dopaminergic neurons together with the fluorescent DA sensor GRABDA1H expressed in cocultured "sniffer" cells. In the presence of the Na+-channel blocker tetrodotoxin to prevent exocytotic DA release, AMPH induced in the cultured neurons a profound dose-dependent efflux of DA that was blocked both by inhibition of DAT with cocaine and by inhibition of the vesicular monoamine transporter-2 with Ro-4-1284 or reserpine. However, the AMPH-induced DA efflux was not accompanied by an increase in cytosolic Ca2+ and was unaffected by blockade of voltage-gated calcium channels or chelation of cytosolic Ca2+. The independence of cytosolic Ca2+ was further supported by activation of N-methyl-D-aspartate-type ionotropic glutamate receptors leading to a marked increase in cytosolic Ca2+ without affecting AMPH-induced DA efflux. Curiously, AMPH elicited spontaneous Ca2+ spikes upon blockade of the D2 receptor, suggesting that AMPH can regulate intracellular Ca2+ in an autoreceptor-dependent manner regardless of the apparent independence of Ca2+ for AMPH-induced efflux. We conclude that AMPH-induced DA efflux in dopaminergic neurons does not require cytosolic Ca2+ but is strictly dependent on the concerted action of AMPH on both vesicular monoamine transporter-2 and DAT.
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Affiliation(s)
- Jonatan Fullerton Støier
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, Panum Institute - Maersk Tower 7.5, University of Copenhagen, Copenhagen, Denmark
| | - Ainoa Konomi-Pilkati
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, Panum Institute - Maersk Tower 7.5, University of Copenhagen, Copenhagen, Denmark
| | - Mia Apuschkin
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, Panum Institute - Maersk Tower 7.5, University of Copenhagen, Copenhagen, Denmark
| | - Freja Herborg
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, Panum Institute - Maersk Tower 7.5, University of Copenhagen, Copenhagen, Denmark
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, Panum Institute - Maersk Tower 7.5, University of Copenhagen, Copenhagen, Denmark.
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6
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Yun S, Yang B, Anair JD, Martin MM, Fleps SW, Pamukcu A, Yeh NH, Contractor A, Kennedy A, Parker JG. Antipsychotic drug efficacy correlates with the modulation of D1 rather than D2 receptor-expressing striatal projection neurons. Nat Neurosci 2023; 26:1417-1428. [PMID: 37443282 PMCID: PMC10842629 DOI: 10.1038/s41593-023-01390-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 06/16/2023] [Indexed: 07/15/2023]
Abstract
Elevated dopamine transmission in psychosis is assumed to unbalance striatal output through D1- and D2-receptor-expressing spiny-projection neurons (SPNs). Antipsychotic drugs are thought to re-balance this output by blocking D2 receptors (D2Rs). In this study, we found that amphetamine-driven dopamine release unbalanced D1-SPN and D2-SPN Ca2+ activity in mice, but that antipsychotic efficacy was associated with the reversal of abnormal D1-SPN, rather than D2-SPN, dynamics, even for drugs that are D2R selective or lacking any dopamine receptor affinity. By contrast, a clinically ineffective drug normalized D2-SPN dynamics but exacerbated D1-SPN dynamics under hyperdopaminergic conditions. Consistent with antipsychotic effect, selective D1-SPN inhibition attenuated amphetamine-driven changes in locomotion, sensorimotor gating and hallucination-like perception. Notably, antipsychotic efficacy correlated with the selective inhibition of D1-SPNs only under hyperdopaminergic conditions-a dopamine-state-dependence exhibited by D1R partial agonism but not non-antipsychotic D1R antagonists. Our findings provide new insights into antipsychotic drug mechanism and reveal an important role for D1-SPN modulation.
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Affiliation(s)
- Seongsik Yun
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Ben Yang
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Justin D Anair
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Madison M Martin
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Stefan W Fleps
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Arin Pamukcu
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Nai-Hsing Yeh
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Anis Contractor
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Ann Kennedy
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Jones G Parker
- Department of Neuroscience, Northwestern University, Chicago, IL, USA.
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7
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Littlepage-Saunders M, Hochstein MJ, Chang DS, Johnson KA. G protein-coupled receptor modulation of striatal dopamine transmission: Implications for psychoactive drug effects. Br J Pharmacol 2023:10.1111/bph.16151. [PMID: 37258878 PMCID: PMC10687321 DOI: 10.1111/bph.16151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/20/2023] [Accepted: 05/23/2023] [Indexed: 06/02/2023] Open
Abstract
Dopamine transmission in the striatum is a critical mediator of the rewarding and reinforcing effects of commonly misused psychoactive drugs. G protein-coupled receptors (GPCRs) that bind a variety of neuromodulators including dopamine, endocannabinoids, acetylcholine and endogenous opioid peptides regulate dopamine release by acting on several components of dopaminergic circuitry. Striatal dopamine release can be driven by both somatic action potential firing and local mechanisms that depend on acetylcholine released from striatal cholinergic interneurons. GPCRs that primarily regulate somatic firing of dopamine neurons via direct effects or modulation of synaptic inputs are likely to affect distinct aspects of behaviour and psychoactive drug actions compared with those GPCRs that primarily regulate local acetylcholine-dependent dopamine release in striatal regions. This review will highlight mechanisms by which GPCRs modulate dopaminergic transmission and the relevance of these findings to psychoactive drug effects on physiology and behaviour.
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Affiliation(s)
- Mydirah Littlepage-Saunders
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
- Neuroscience Graduate Program, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Michael J Hochstein
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Doris S Chang
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Kari A Johnson
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
- Neuroscience Graduate Program, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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8
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Mazzeo F, Meccariello R, Guatteo E. Molecular and Epigenetic Aspects of Opioid Receptors in Drug Addiction and Pain Management in Sport. Int J Mol Sci 2023; 24:ijms24097831. [PMID: 37175536 PMCID: PMC10178540 DOI: 10.3390/ijms24097831] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/14/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023] Open
Abstract
Opioids are substances derived from opium (natural opioids). In its raw state, opium is a gummy latex extracted from Papaver somniferum. The use of opioids and their negative health consequences among people who use drugs have been studied. Today, opioids are still the most commonly used and effective analgesic treatments for severe pain, but their use and abuse causes detrimental side effects for health, including addiction, thus impacting the user's quality of life and causing overdose. The mesocorticolimbic dopaminergic circuitry represents the brain circuit mediating both natural rewards and the rewarding aspects of nearly all drugs of abuse, including opioids. Hence, understanding how opioids affect the function of dopaminergic circuitry may be useful for better knowledge of the process and to develop effective therapeutic strategies in addiction. The aim of this review was to summarize the main features of opioids and opioid receptors and focus on the molecular and upcoming epigenetic mechanisms leading to opioid addiction. Since synthetic opioids can be effective for pain management, their ability to induce addiction in athletes, with the risk of incurring doping, is also discussed.
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Affiliation(s)
- Filomena Mazzeo
- Department of Economics, Law, Cybersecurity and Sports Sciences, University of Naples "Parthenope", 80133 Naples, Italy
- Department of Movement Sciences and Wellbeing, University of Naples "Parthenope", 80133 Naples, Italy
| | - Rosaria Meccariello
- Department of Movement Sciences and Wellbeing, University of Naples "Parthenope", 80133 Naples, Italy
| | - Ezia Guatteo
- Department of Movement Sciences and Wellbeing, University of Naples "Parthenope", 80133 Naples, Italy
- IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 64, 00143 Rome, Italy
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9
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Skiteva O, Yao N, Mantas I, Zhang X, Perlmann T, Svenningsson P, Chergui K. Aberrant somatic calcium channel function in cNurr1 and LRRK2-G2019S mice. NPJ Parkinsons Dis 2023; 9:56. [PMID: 37029193 PMCID: PMC10082048 DOI: 10.1038/s41531-023-00500-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 03/23/2023] [Indexed: 04/09/2023] Open
Abstract
In Parkinson's disease (PD), axons of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) degenerate before their cell bodies. Calcium influx during pacemaker firing might contribute to neuronal loss, but it is not known if dysfunctions of voltage-gated calcium channels (VGCCs) occur in DA neurons somata and axon terminals. We investigated T-type and L-type VGCCs in SNc-DA neurons of two mouse models of PD: mice with a deletion of the Nurr1 gene in DA neurons from an adult age (cNurr1 mice), and mice bearing the G2019S mutation in the gene coding for LRRK2 (G2019S mice). Adult cNurr1 mice displayed motor and DA deficits, while middle-aged G2019S mice did not. The number and morphology of SNc-DA neurons, most of their intrinsic membrane properties and pacemaker firing were unaltered in cNurr1 and G2019S mice compared to their control and wild-type littermates. L-type VGCCs contributed to the pacemaker firing of SNc-DA neurons in G2019S mice, but not in control, wild-type, and cNurr1 mice. In cNurr1 mice, but not G2019S mice, the contribution of T-type VGCCs to the pacemaker firing of SNc-DA neurons was reduced, and somatic dopamine-D2 autoreceptors desensitized more. Altered contribution of L-type and T-type VGCCs to the pacemaker firing was not observed in the presence of a LRRK2 kinase inhibitor in G2019S mice, and in the presence of a flavonoid with antioxidant activity in G2019S and cNurr1 mice. The role of L-type and T-type VGCCs in controlling dopamine release from axon terminals in the striatum was unaltered in cNurr1 and G2019S mice. Our findings uncover opposite changes, linked to oxidative stress, in the function of two VGCCs in DA neurons somata, but not axon terminals, in two different experimental PD models.
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Affiliation(s)
- Olga Skiteva
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ning Yao
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ioannis Mantas
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Xiaoqun Zhang
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Thomas Perlmann
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Per Svenningsson
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Karima Chergui
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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10
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Bono F, Fiorentini C, Mutti V, Tomasoni Z, Sbrini G, Trebesova H, Marchi M, Grilli M, Missale C. Central nervous system interaction and crosstalk between nAChRs and other ionotropic and metabotropic neurotransmitter receptors. Pharmacol Res 2023; 190:106711. [PMID: 36854367 DOI: 10.1016/j.phrs.2023.106711] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/20/2023] [Accepted: 02/24/2023] [Indexed: 02/27/2023]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are widely distributed in both the peripheral and the central nervous systems. nAChRs exert a crucial modulatory influence on several brain biological processes; they are involved in a variety of neuronal diseases including Parkinson's disease, Alzheimer's disease, epilepsy, and nicotine addiction. The influence of nAChRs on brain function depends on the activity of other neurotransmitter receptors that co-exist with nAChRs on neurons. In fact, the crosstalk between receptors is an important mechanism of neurotransmission modulation and plasticity. This may be due to converging intracellular pathways but also occurs at the membrane level, because of direct physical interactions between receptors. In this line, this review is dedicated to summarizing how nAChRs and other ionotropic and metabotropic receptors interact and the relevance of nAChRs cross-talks in modulating various neuronal processes ranging from the classical modulation of neurotransmitter release to neuron plasticity and neuroprotection.
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Affiliation(s)
- Federica Bono
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Chiara Fiorentini
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Veronica Mutti
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Zaira Tomasoni
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Giulia Sbrini
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Hanna Trebesova
- Department of Pharmacy, University of Genova, 16148 Genoa, Italy
| | - Mario Marchi
- Department of Pharmacy, University of Genova, 16148 Genoa, Italy
| | - Massimo Grilli
- Department of Pharmacy, University of Genova, 16148 Genoa, Italy.
| | - Cristina Missale
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
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11
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Tomagra G, Franchino C, Cesano F, Chiarion G, de lure A, Carbone E, Calabresi P, Mesin L, Picconi B, Marcantoni A, Carabelli V. Alpha-synuclein oligomers alter the spontaneous firing discharge of cultured midbrain neurons. Front Cell Neurosci 2023; 17:1078550. [PMID: 36744002 PMCID: PMC9896582 DOI: 10.3389/fncel.2023.1078550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/06/2023] [Indexed: 01/21/2023] Open
Abstract
The aim of this work was to monitor the effects of extracellular α-synuclein on the firing activity of midbrain neurons dissociated from substantia nigra TH-GFP mice embryos and cultured on microelectrode arrays (MEA). We monitored the spontaneous firing discharge of the network for 21 days after plating and the role of glutamatergic and GABAergic inputs in regulating burst generation and network synchronism. Addition of GABA A , AMPA and NMDA antagonists did not suppress the spontaneous activity but allowed to identify three types of neurons that exhibited different modalities of firing and response to applied L-DOPA: high-rate (HR) neurons, low-rate pacemaking (LR-p), and low-rate non-pacemaking (LR-np) neurons. Most HR neurons were insensitive to L-DOPA, while the majority of LR-p neurons responded with a decrease of the firing discharge; less defined was the response of LR-np neurons. The effect of exogenous α-synuclein (α-syn) on the firing discharge of midbrain neurons was then studied by varying the exposure time (0-48 h) and the α-syn concentration (0.3-70 μM), while the formation of α-syn oligomers was monitored by means of AFM. Independently of the applied concentration, acute exposure to α-syn monomers did not exert any effect on the spontaneous firing rate of HR, LR-p, and LR-np neurons. On the contrary, after 48 h exposure, the firing activity was drastically altered at late developmental stages (14 days in vitro, DIV, neurons): α-syn oligomers progressively reduced the spontaneous firing discharge (IC50 = 1.03 μM), impaired burst generation and network synchronism, proportionally to the increased oligomer/monomer ratio. Different effects were found on early-stage developed neurons (9 DIV), whose firing discharge remained unaltered, regardless of the applied α-syn concentration and the exposure time. Our findings unravel, for the first time, the variable effects of exogenous α-syn at different stages of midbrain network development and provide new evidence for the early detection of neuronal function impairment associated to aggregated forms of α-syn.
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Affiliation(s)
- Giulia Tomagra
- Drug Science Department, University of Torino, Turin, Italy
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
| | | | - Federico Cesano
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
- Department of Chemistry and INSTM-UdR Torino, Turin, Italy
| | - Giovanni Chiarion
- Mathematical Biology and Physiology, Department of Electronics and Telecommunications, Turin, Italy
| | - Antonio de lure
- Laboratory Experimental Neurophysiology, IRCCS San Raffaele Rome, Rome, Italy
| | - Emilio Carbone
- Drug Science Department, University of Torino, Turin, Italy
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
| | - Paolo Calabresi
- Neurological Clinic, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
- Neurology, Department of Neuroscience, Faculty of Medicine, Università Cattolica del “Sacro Cuore,”Rome, Italy
| | - Luca Mesin
- Mathematical Biology and Physiology, Department of Electronics and Telecommunications, Turin, Italy
| | - Barbara Picconi
- Laboratory Experimental Neurophysiology, IRCCS San Raffaele Rome, Rome, Italy
- Dipartimento di Scienze Umane e Promozione della Qualitá della Vita, Telematic University San Raffaele Roma, Rome, Italy
| | - Andrea Marcantoni
- Drug Science Department, University of Torino, Turin, Italy
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
| | - Valentina Carabelli
- Drug Science Department, University of Torino, Turin, Italy
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
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12
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Chen XY, Liu C, Xue Y, Chen L. Changed firing activity of nigra dopaminergic neurons in Parkinson's disease. Neurochem Int 2023; 162:105465. [PMID: 36563966 DOI: 10.1016/j.neuint.2022.105465] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/11/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
Parkinson's disease is the second most common neurodegenerative disease which is characterized by selective degeneration of dopaminergic neurons in the substantia nigra pars compacta. The intrinsic neuronal firing activity is critical for the functional organization of brain and the specific deficits of neuronal firing activity may be associated with different brain disorders. It is known that the surviving nigra dopaminergic neurons exhibit altered firing activity, such as decreased spontaneous firing frequency, reduced number of firing neurons and increased burst firing in Parkinson's disease. Several ionic mechanisms are involved in changed firing activity of dopaminergic neurons under parkinsonian state. In this review, we summarize the changes of spontaneous firing activity as well as the possible mechanisms of nigra dopaminergic neurons in Parkinson's disease. This review may let us clearly understand the involvement of neuronal firing activity of nigra dopaminergic neurons in Parkinson's disease.
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Affiliation(s)
- Xin-Yi Chen
- Department of International Medicine, Affiliated Hospital of Qingdao University, Qingdao, China.
| | - Cui Liu
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Yan Xue
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Lei Chen
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China.
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13
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Brandner DD, Retzlaff CL, Kocharian A, Stieve BJ, Mashal MA, Mermelstein PG, Rothwell PE. Neuroligin-3 in dopaminergic circuits promotes behavioural and neurobiological adaptations to chronic morphine exposure. Addict Biol 2023; 28:e13247. [PMID: 36577719 PMCID: PMC9803875 DOI: 10.1111/adb.13247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 09/30/2022] [Accepted: 10/12/2022] [Indexed: 12/12/2022]
Abstract
Chronic opioid exposure causes structural and functional changes in brain circuits, which may contribute to opioid use disorders. Synaptic cell-adhesion molecules are prime candidates for mediating this opioid-evoked plasticity. Neuroligin-3 (NL3) is an X-linked postsynaptic adhesion protein that shapes synaptic function at multiple sites in the mesolimbic dopamine system. We therefore studied how genetic knockout of NL3 alters responses to chronic morphine in male mice. Constitutive NL3 knockout caused a persistent reduction in psychomotor sensitization after chronic morphine exposure and change in the topography of locomotor stimulation produced by morphine. This latter change was recapitulated by conditional genetic deletion of NL3 from cells expressing the Drd1 dopamine receptor, whereas reduced psychomotor sensitization was recapitulated by conditional genetic deletion from dopamine neurons. Without NL3 expression, dopamine neurons in the ventral tegmental area exhibited diminished activation following chronic morphine exposure, by measuring in vivo calcium signals with fibre photometry. This altered pattern of dopamine neuron activity may be driven by aberrant forms of opioid-evoked synaptic plasticity in the absence of NL3: dopamine neurons lacking NL3 showed weaker synaptic inhibition at baseline, which was subsequently strengthened after chronic morphine. In total, our study highlights neurobiological adaptations in dopamine neurons of the ventral tegmental area that correspond with increased behavioural sensitivity to opioids and further suggests that NL3 expression by dopamine neurons provides a molecular substrate for opioid-evoked adaptations in brain function and behaviour.
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Affiliation(s)
- Dieter D. Brandner
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, 55455,Medical Scientist Training Program, University of Minnesota, Minneapolis, MN, 55455
| | | | - Adrina Kocharian
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, 55455,Medical Scientist Training Program, University of Minnesota, Minneapolis, MN, 55455
| | - Bethany J. Stieve
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, 55455
| | - Mohammed A. Mashal
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455
| | | | - Patrick E. Rothwell
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455,Corresponding Author: Patrick E. Rothwell, Ph.D., 4-142 Wallin Medical Biosciences Building, 2101 6 Street SE, Minneapolis, MN, 55455, Phone: 612-626-8744,
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14
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Kawahata I, Fukunaga K. Endocytosis of dopamine receptor: Signaling in brain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 196:99-111. [PMID: 36813367 DOI: 10.1016/bs.pmbts.2022.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
This chapter describes the physiological significance of dopamine receptor endocytosis and the consequence of the receptor signaling. Endocytosis of dopamine receptors is regulated by many components such as clathrin, β-arrestin, caveolin, and Rab family proteins. The dopamine receptors escape from lysosomal digestion, and their recycling occurs rapidly, reinforcing the dopaminergic signal transduction. In addition, the pathological impact of the receptors interacting with specific proteins has been the focus of much attention. Based on this background, this chapter provides an in-depth understanding of the mechanisms of molecules interacting with dopamine receptors and discusses the potential pharmacotherapeutic targets for α-synucleinopathies and neuropsychiatric disorders.
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Affiliation(s)
- Ichiro Kawahata
- Department of CNS drug innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
| | - Kohji Fukunaga
- Department of CNS drug innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
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15
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Condon AF, Asad N, Dore TM, Williams JT. Co-activation of GPCRs facilitate GIRK-dependent current. J Physiol 2022; 600:4881-4895. [PMID: 36121348 DOI: 10.1113/jp283590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/09/2022] [Indexed: 12/24/2022] Open
Abstract
The activity of dopamine neurons is dependent on both intrinsic properties and afferent projections. One potent form of inhibition is mediated by the activation of two inhibitory G protein-coupled receptors, D2 and GABAB receptors. Each of these receptors activates G protein-coupled inwardly rectifying potassium (GIRK) channels. Recordings in brain slices have shown that co-activation using saturating concentrations of agonists results in occlusion of the GIRK current. The present study examined the interaction between D2 and GABAB receptors using transient applications of sub-saturating concentrations of agonists where the co-application of one agonist resulted in both facilitation and inhibition (desensitization) of the other. The heterologous facilitation was modelled based on the known cooperative interaction between the G protein βγ subunits and GIRK channels. The results indicate that a low tonic level of G βγ results in facilitation of GIRK current and a high level of G βγ results in occlusion. The kinetics of the current induced by transient receptor activation is prolonged in each case. The results suggest that the cooperative interaction between G βγ subunits and GIRK channels determines both the amplitude and kinetics of GPCR-dependent current. KEY POINTS: Inhibitory D2 and GABAB receptors modulate dopamine neuron activity through shared G protein-coupled inwardly rectifying potassium (GIRK) channels. This study reports robust bidirectional interactions between these two converging receptor pathways. Coincident activation of D2 and GABAB receptors leads to facilitation of GIRK channel currents, augmenting both amplitude and prolonging the duration of phasic responses. Activation of either D2 or GABAB receptors also acutely desensitized the GIRK channel current induced by D2 receptor activation that rapidly recovers following termination of desensitizing stimulus. Results demonstrate that the activity of either G protein-coupled receptor system must be considered in the context of other G protein-coupled receptors.
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Affiliation(s)
- Alec F Condon
- The Vollum Institute, Oregon Health Sciences University, Portland, USA
| | - Naeem Asad
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | - Timothy M Dore
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | - John T Williams
- The Vollum Institute, Oregon Health Sciences University, Portland, USA
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16
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Liu H, Tritsch NX. G protein-coupled receptors cooperate to silence dopamine neurons. J Physiol 2022; 600:4773-4774. [PMID: 36214545 DOI: 10.1113/jp283842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Haixin Liu
- Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, USA.,Fresco Institute for Parkinson's and Movement Disorders, New York University Langone Health, New York, NY, USA
| | - Nicolas X Tritsch
- Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, USA.,Fresco Institute for Parkinson's and Movement Disorders, New York University Langone Health, New York, NY, USA
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17
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Partial Ablation of Postsynaptic Dopamine D2 Receptors in the Central Nucleus of the Amygdala Increases Risk Avoidance in Exploratory Tasks. eNeuro 2022; 9:ENEURO.0528-21.2022. [PMID: 35210287 PMCID: PMC8925651 DOI: 10.1523/eneuro.0528-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/15/2022] [Accepted: 02/04/2022] [Indexed: 12/05/2022] Open
Abstract
The central nucleus of the amygdala (CeA) is involved in the expression of fear and has been implicated in several anxiety disorders. This structure is densely innervated by DAergic projections that impinge on amygdalar neurons expressing various dopamine (DA) receptor subtypes, including D2 receptors (D2Rs). Although various pharmacological approaches have assessed the role of D2Rs in the CeA, the actual participation of postsynaptic D2Rs in the CeA to defensive behaviors remains unclear. Here, we investigated the distribution of D2Rs in the CeA and their role in modifying neuronal activity and fear related behaviors in mice. First, using the mouse reporter strain D2R-EGFP, we verified that D2Rs are present both in neurons of the CeA and in A10 dorsocaudal (A10dc) DAergic neurons that innervate the CeA. Moreover, we showed that pharmacological stimulation of D2Rs increases the activity of protein kinase C (PKC)δ cells present in the CeA, a type of neuron previously associated with reduced defensive behaviors. Finally, using a molecular genetics approach that discriminates postsynaptic D2Rs from presynaptic D2 autoreceptors, we demonstrated that mice carrying targeted deletions of postsynaptic D2Rs in the CeA display increased risk avoidance in exploratory tasks. Together, our results indicate that postsynaptic D2Rs in the CeA attenuate behavioral reactions to potential environmental threats.
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18
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Dopamine D2 receptors modulate the cholinergic pause and inhibitory learning. Mol Psychiatry 2022; 27:1502-1514. [PMID: 34789847 PMCID: PMC9106808 DOI: 10.1038/s41380-021-01364-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 01/10/2023]
Abstract
Cholinergic interneurons (CINs) in the striatum respond to salient stimuli with a multiphasic response, including a pause, in neuronal activity. Slice-physiology experiments have shown the importance of dopamine D2 receptors (D2Rs) in regulating CIN pausing, yet the behavioral significance of the CIN pause and its regulation by dopamine in vivo is still unclear. Here, we show that D2R upregulation in CINs of the nucleus accumbens (NAc) lengthens the pause in CIN activity ex vivo and enlarges a stimulus-evoked decrease in acetylcholine (ACh) levels during behavior. This enhanced dip in ACh levels is associated with a selective deficit in the learning to inhibit responding in a Go/No-Go task. Our data demonstrate, therefore, the importance of CIN D2Rs in modulating the CIN response induced by salient stimuli and point to a role of this response in inhibitory learning. This work has important implications for brain disorders with altered striatal dopamine and ACh function, including schizophrenia and attention-deficit hyperactivity disorder (ADHD).
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19
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Aripiprazole Offsets Mutant ATXN3-Induced Motor Dysfunction by Targeting Dopamine D2 and Serotonin 1A and 2A Receptors in C. elegans. Biomedicines 2022; 10:biomedicines10020370. [PMID: 35203579 PMCID: PMC8962381 DOI: 10.3390/biomedicines10020370] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 01/14/2023] Open
Abstract
The atypical antipsychotic aripiprazole is a Food and Drug Administration-approved drug for the treatment of psychotic, mood, and other psychiatric disorders. Previous drug discovery efforts pinpointed aripiprazole as an effective suppressor of Machado–Joseph disease (MJD) pathogenesis, as its administration resulted in a reduced abundance and aggregation of mutant Ataxin-3 (ATXN3) proteins. Dopamine partial agonism and functional selectivity have been proposed as the main pharmacological mechanism of action of aripiprazole in the treatment of psychosis; however, this mechanism remains to be determined in the context of MJD. Here, we focus on confirming the efficacy of aripiprazole to reduce motor dysfunction in vivo, using a Caenorhabditis elegans (C. elegans) model of MJD, and on unveiling the drug targets required for its positive action against mutant ATXN3 pathogenesis. We employed pharmacogenetics and pharmacological approaches to identify which dopamine and serotonin receptors are critical for aripiprazole-mediated improvements in motor function. We demonstrated that dopamine D2-like and serotonin 5-HT1A and 5-HT2A receptors play important roles in this process. Our findings strengthen the relevance of dopaminergic and serotoninergic signaling modulation against mutant ATXN3-mediated pathogenesis. The identification of aripiprazole’s cellular targets, relevant for MJD and perhaps other neurodegenerative diseases, may pave the way for prospective drug discovery and development campaigns aiming to improve the features of this prototypical compound and reduce side effects not negligible in the case of aripiprazole.
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20
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Simpson EH, Gallo EF, Balsam PD, Javitch JA, Kellendonk C. How changes in dopamine D2 receptor levels alter striatal circuit function and motivation. Mol Psychiatry 2022; 27:436-444. [PMID: 34385603 PMCID: PMC8837728 DOI: 10.1038/s41380-021-01253-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/27/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023]
Abstract
It was first posited, more than five decades ago, that the etiology of schizophrenia involves overstimulation of dopamine receptors. Since then, advanced clinical research methods, including brain imaging, have refined our understanding of the relationship between striatal dopamine and clinical phenotypes as well as disease trajectory. These studies point to striatal dopamine D2 receptors, the main target for all current antipsychotic medications, as being involved in both positive and negative symptoms. Simultaneously, animal models have been central to investigating causal relationships between striatal dopamine D2 receptors and behavioral phenotypes relevant to schizophrenia. We begin this article by reviewing the circuit, cell-type and subcellular locations of dopamine D2 receptors and their downstream signaling pathways. We then summarize results from several mouse models in which D2 receptor levels were altered in various brain regions, cell-types and developmental periods. Behavioral, electrophysiological and anatomical consequences of these D2 receptor perturbations are reviewed with a selective focus on striatal circuit function and alterations in motivated behavior, a core negative symptom of schizophrenia. These studies show that D2 receptors serve distinct physiological roles in different cell types and at different developmental time points, regulating motivated behaviors in sometimes opposing ways. We conclude by considering the clinical implications of this complex regulation of striatal circuit function by D2 receptors.
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Affiliation(s)
- Eleanor H. Simpson
- Division of Developmental Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, United States,Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, United States
| | - Eduardo F. Gallo
- Department of Biological Sciences, Fordham University, 441 East Fordham Road, Bronx, NY 10458
| | - Peter D. Balsam
- Division of Developmental Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, United States,Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, United States,Department of Psychology, Barnard College, 3009 Broadway, New York, NY 10027,Department of Psychology, Columbia University, 1190 Amsterdam Ave, New York, NY 10027
| | - Jonathan A. Javitch
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, United States,Division of Molecular Therapeutics, New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032,Department of Molecular Pharmacology and Therapeutics, Columbia University, 1051 Riverside Drive, New York, NY 10032
| | - Christoph Kellendonk
- Department of Psychiatry, Columbia University, New York, NY, USA. .,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA. .,Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA.
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21
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Dagra A, Miller DR, Lin M, Gopinath A, Shaerzadeh F, Harris S, Sorrentino ZA, Støier JF, Velasco S, Azar J, Alonge AR, Lebowitz JJ, Ulm B, Bu M, Hansen CA, Urs N, Giasson BI, Khoshbouei H. α-Synuclein-induced dysregulation of neuronal activity contributes to murine dopamine neuron vulnerability. NPJ Parkinsons Dis 2021; 7:76. [PMID: 34408150 PMCID: PMC8373893 DOI: 10.1038/s41531-021-00210-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 07/09/2021] [Indexed: 02/07/2023] Open
Abstract
Pathophysiological damages and loss of function of dopamine neurons precede their demise and contribute to the early phases of Parkinson's disease. The presence of aberrant intracellular pathological inclusions of the protein α-synuclein within ventral midbrain dopaminergic neurons is one of the cardinal features of Parkinson's disease. We employed molecular biology, electrophysiology, and live-cell imaging to investigate how excessive α-synuclein expression alters multiple characteristics of dopaminergic neuronal dynamics and dopamine transmission in cultured dopamine neurons conditionally expressing GCaMP6f. We found that overexpression of α-synuclein in mouse (male and female) dopaminergic neurons altered neuronal firing properties, calcium dynamics, dopamine release, protein expression, and morphology. Moreover, prolonged exposure to the D2 receptor agonist, quinpirole, rescues many of the alterations induced by α-synuclein overexpression. These studies demonstrate that α-synuclein dysregulation of neuronal activity contributes to the vulnerability of dopaminergic neurons and that modulation of D2 receptor activity can ameliorate the pathophysiology. These findings provide mechanistic insights into the insidious changes in dopaminergic neuronal activity and neuronal loss that characterize Parkinson's disease progression with significant therapeutic implications.
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Affiliation(s)
- Abeer Dagra
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Douglas R. Miller
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Min Lin
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Adithya Gopinath
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Fatemeh Shaerzadeh
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Sharonda Harris
- grid.15276.370000 0004 1936 8091Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL USA
| | - Zachary A. Sorrentino
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Jonatan Fullerton Støier
- grid.5254.60000 0001 0674 042XMolecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sophia Velasco
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Janelle Azar
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Adetola R. Alonge
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Joseph J. Lebowitz
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Brittany Ulm
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Mengfei Bu
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Carissa A. Hansen
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Nikhil Urs
- grid.15276.370000 0004 1936 8091Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL USA
| | - Benoit I. Giasson
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Habibeh Khoshbouei
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
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22
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Condon AF, Robinson BG, Asad N, Dore TM, Tian L, Williams JT. The residence of synaptically released dopamine on D2 autoreceptors. Cell Rep 2021; 36:109465. [PMID: 34348146 PMCID: PMC8351352 DOI: 10.1016/j.celrep.2021.109465] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/24/2021] [Accepted: 07/08/2021] [Indexed: 11/30/2022] Open
Abstract
Neuromodulation mediated by synaptically released endogenous transmitters acting in G-protein-coupled receptors (GPCRs) is slow primarily because of multistep downstream signaling. What is less well understood is the spatial and temporal kinetics of transmitter and receptor interaction. The present work uses the combination of the dopamine sensor, dLight, to detect the spatial release and diffusion of dopamine and a caged form of a D2-dopamine receptor antagonist, CyHQ-sulpiride, to rapidly block the D2 autoreceptors. Photoactivation of the CyHQ-sulpiride blocks receptors in milliseconds such that the time course of dopamine/receptor interaction is mapped onto the downstream signaling. The results show that highly localized release, but not dopamine diffusion, defines the time course of the functional interaction between dopamine and D2 autoreceptors, which determines downstream inhibition.
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Affiliation(s)
- Alec F Condon
- The Vollum Institute, Oregon Health Sciences University, Portland, OR, USA
| | - Brooks G Robinson
- The Vollum Institute, Oregon Health Sciences University, Portland, OR, USA
| | - Naeem Asad
- New York University Abu Dhabi, Saadiyat Island, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Timothy M Dore
- New York University Abu Dhabi, Saadiyat Island, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, USA
| | - John T Williams
- The Vollum Institute, Oregon Health Sciences University, Portland, OR, USA.
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23
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Escobar AP, Martínez-Pinto J, Silva-Olivares F, Sotomayor-Zárate R, Moya PR. Altered Grooming Syntax and Amphetamine-Induced Dopamine Release in EAAT3 Overexpressing Mice. Front Cell Neurosci 2021; 15:661478. [PMID: 34234648 PMCID: PMC8255620 DOI: 10.3389/fncel.2021.661478] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 05/17/2021] [Indexed: 01/06/2023] Open
Abstract
The excitatory amino acid transporter EAAT3 plays an important role in the neuronal uptake of glutamate regulating the activation of glutamate receptors. Polymorphisms in the gene-encoding EAAT3 have been associated with obsessive-compulsive disorder (OCD), although the mechanisms underlying this relationship are still unknown. We recently reported that mice with increased EAAT3 expression in forebrain neurons (EAAT3 g lo /CMKII) display behavioral and synaptic features relevant to OCD, including increased grooming, higher anxiety-like behavior and altered cortico-striatal synaptic function. The dopamine neurotransmitter system is implicated in ritualistic behaviors. Indeed, dopaminergic neurons express EAAT3, and mice lacking EAAT3 exhibit decreased dopamine release and decreased expression of the dopamine D1 receptor. Moreover, EAAT3 plays a role on the effect of the psychostimulant amphetamine. As such, we sought to determine if the OCD-like behavior in EAAT3 g lo /CMKII mice is accompanied by altered nigro-striatal dopaminergic transmission. The aim of this study was to analyze dopamine transmission both in basal conditions and after an acute challenge of amphetamine, using behavioral, neurochemical, molecular, and cellular approaches. We found that in basal conditions, EAAT3 g lo /CMKII mice performed more grooming events and that they remained in phase 1 of the grooming chain syntax compared with control littermates. Administration of amphetamine increased the number of grooming events in control mice, while EAAT3 g lo /CMKII mice remain unaffected. Interestingly, the grooming syntax of amphetamine-control mice resembled that of EAAT3 g lo /CMKII mice in basal conditions. Using in vivo microdialysis, we found decreased basal dopamine levels in EAAT3 g lo /CMKII compared with control mice. Unexpectedly, we found that after acute amphetamine, EAAT3 g lo /CMKII mice had a higher release of dopamine compared with that of control mice, suggesting that EAAT3 overexpression leads to increased dopamine releasability. To determine postsynaptic effect of EAAT3 overexpression over dopamine transmission, we performed Western blot analysis of dopaminergic proteins and found that EAAT3 g lo /CMKII mice have higher expression of D2 receptors, suggesting a higher inhibition of the indirect striatal pathway. Together, the data indicate that EAAT3 overexpression impacts on dopamine transmission, making dopamine neurons more sensitive to the effect of amphetamine and leading to a disbalance between the direct and indirect striatal pathways that favors the performance of repetitive behaviors.
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Affiliation(s)
- Angélica P Escobar
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de Valparaíso, Valparaiso, Chile.,Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso, Valparaiso, Chile
| | - Jonathan Martínez-Pinto
- Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso, Valparaiso, Chile.,Facultad de Ciencias, Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Universidad de Valparaíso, Valparaiso, Chile
| | - Francisco Silva-Olivares
- Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso, Valparaiso, Chile.,Facultad de Ciencias, Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Universidad de Valparaíso, Valparaiso, Chile
| | - Ramón Sotomayor-Zárate
- Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso, Valparaiso, Chile.,Facultad de Ciencias, Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Universidad de Valparaíso, Valparaiso, Chile
| | - Pablo R Moya
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de Valparaíso, Valparaiso, Chile.,Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso, Valparaiso, Chile
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24
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Lin M, Mackie PM, Shaerzadeh F, Gamble-George J, Miller DR, Martyniuk CJ, Khoshbouei H. In Parkinson's patient-derived dopamine neurons, the triplication of α-synuclein locus induces distinctive firing pattern by impeding D2 receptor autoinhibition. Acta Neuropathol Commun 2021; 9:107. [PMID: 34099060 PMCID: PMC8185945 DOI: 10.1186/s40478-021-01203-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/17/2021] [Indexed: 12/12/2022] Open
Abstract
Pathophysiological changes in dopamine neurons precede their demise and contribute to the early phases of Parkinson's disease (PD). Intracellular pathological inclusions of the protein α-synuclein within dopaminergic neurons are a cardinal feature of PD, but the mechanisms by which α-synuclein contributes to dopaminergic neuron vulnerability remain unknown. The inaccessibility to diseased tissue has been a limitation in studying progression of pathophysiology prior to degeneration of dopamine neurons. To address these issues, we differentiated induced pluripotent stem cells (iPSCs) from a PD patient carrying the α-synuclein triplication mutation (AST) and an unaffected first-degree relative (NAS) into dopaminergic neurons. In human-like dopamine neurons α-synuclein overexpression reduced the functional availability of D2 receptors, resulting in a stark dysregulation in firing activity, dopamine release, and neuronal morphology. We back-translated these findings into primary mouse neurons overexpressing α-synuclein and found a similar phenotype, supporting the causal role for α-synuclein. Importantly, application of D2 receptor agonist, quinpirole, restored the altered firing activity of AST-derived dopaminergic neurons to normal levels. These results provide novel insights into the pre-degenerative pathophysiological neuro-phenotype induced by α-synuclein overexpression and introduce a potential mechanism for the long-established clinical efficacy of D2 receptor agonists in the treatment of PD.
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Affiliation(s)
- Min Lin
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Phillip M Mackie
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Fatima Shaerzadeh
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | | | - Douglas R Miller
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Chris J Martyniuk
- Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Habibeh Khoshbouei
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA.
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Inhibitory Effect of Apomorphine on Focal and Nonfocal Plasticity in the Human Motor Cortex. Pharmaceutics 2021; 13:pharmaceutics13050718. [PMID: 34068263 PMCID: PMC8153161 DOI: 10.3390/pharmaceutics13050718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 12/02/2022] Open
Abstract
Dopamine is crucial for neuroplasticity, which is considered to be the neurophysiological foundation of learning and memory. The specific effect of dopamine on plasticity such as long-term potentiation (LTP) and long-term depression (LTD) is determined by receptor subtype specificity, concentration level, and the kind of plasticity induction technique. In healthy human subjects, the dopamine precursor levodopa (L-DOPA) exerts a dosage-dependent non-linear effect on motor cortex plasticity. Low and high dosage L-DOPA impaired or abolished plasticity, while medium-dose preserved and reversed plasticity in previous studies. Similar dosage-dependent effects were also observed for selective D1-like and D2-like receptor activation that favor excitatory and inhibitory plasticity, respectively. However, such a dosage-dependent effect has not been explored for a nonselective dopamine agonist such as apomorphine in humans. To this aim, nonfocal and focal motor cortex plasticity induction using paired associative stimulation (PAS) and transcranial direct current stimulation (tDCS) were performed respectively in healthy participants under 0.1, 0.2, 0.3 mg apomorphine or placebo drug. Transcranial magnetic stimulation-elicited motor-evoked potentials were used to monitor motor cortical excitability alterations. We hypothesized that, similar to L-DOPA, apomorphine will affect motor cortex plasticity. The results showed that apomorphine with the applied dosages has an inhibitory effect for focal and nonfocal LTP-like and LTD-like plasticity, which was either abolished, diminished or reversed. The detrimental effect on plasticity induction under all dosages of apomorphine suggests a predominantly presynaptic mechanism of action of these dosages.
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Ethanol inhibition of lateral orbitofrontal cortex neuron excitability is mediated via dopamine D1/D5 receptor-induced release of astrocytic glycine. Neuropharmacology 2021; 192:108600. [PMID: 33965399 DOI: 10.1016/j.neuropharm.2021.108600] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/16/2021] [Accepted: 04/30/2021] [Indexed: 01/25/2023]
Abstract
Recent findings from this laboratory demonstrate that ethanol reduces the intrinsic excitability of orbitofrontal cortex (OFC) neurons via activation of strychnine-sensitive glycine receptors. Although the mechanism linking ethanol to the release of glycine is currently unknown, astrocytes are a source of neurotransmitters including glycine and activation of dopamine D1-like receptors has been reported to enhance extracellular levels of glycine via a functional reversal of the astrocytic glycine transporter GlyT1. We recently reported that like ethanol, dopamine or a D1/D5 receptor agonist increases a tonic current in lateral OFC (lOFC) neurons. Therefore, in this study, we used whole-cell patch-clamp electrophysiology to examine whether ethanol inhibition of OFC spiking involves the release of glycine from astrocytes and whether this release is dopamine receptor dependent. Ethanol, applied acutely, decreased spiking of lOFC neurons and this effect was blocked by antagonists of GlyT1, the norepinephrine transporter or D1-like but not D2-like receptors. Ethanol enhanced the tonic current of OFC neurons and occluded the effect of dopamine suggesting that ethanol and dopamine may share a common pathway. Altering astrocyte function by suppressing intracellular astrocytic calcium signaling or blocking the astrocyte-specific Kir4.1 potassium channels reduced but did not completely abolish ethanol inhibition of OFC neuron firing. However, when both astrocytic calcium signaling and Kir4.1 channels were inhibited, ethanol had no effect on firing. Ethanol inhibition was also prevented by inhibitors of phospholipase C and conventional isoforms of protein kinase C (cPKC) previously shown to block D1R-induced GlyT1 reversal and PKC inhibition of Kir4.1 channels. Finally, the membrane potential of OFC astrocytes was depolarized by bath application of a Kir4.1 blocker, a D1 agonist or ethanol and ethanol effect was blocked by a D1 antagonist. Together, these findings suggest that acute ethanol inhibits OFC neuron excitability via a D1 receptor-mediated dysregulation of astrocytic glycine transport.
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Mannal N, Kleiner K, Fauler M, Dougalis A, Poetschke C, Liss B. Multi-Electrode Array Analysis Identifies Complex Dopamine Responses and Glucose Sensing Properties of Substantia Nigra Neurons in Mouse Brain Slices. Front Synaptic Neurosci 2021; 13:635050. [PMID: 33716704 PMCID: PMC7952765 DOI: 10.3389/fnsyn.2021.635050] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 01/08/2021] [Indexed: 12/16/2022] Open
Abstract
Dopaminergic (DA) midbrain neurons within the substantia nigra (SN) display an autonomous pacemaker activity that is crucial for dopamine release and voluntary movement control. Their progressive degeneration is a hallmark of Parkinson's disease. Their metabolically demanding activity-mode affects Ca2+ homeostasis, elevates metabolic stress, and renders SN DA neurons particularly vulnerable to degenerative stressors. Accordingly, their activity is regulated by complex mechanisms, notably by dopamine itself, via inhibitory D2-autoreceptors and the neuroprotective neuronal Ca2+ sensor NCS-1. Analyzing regulation of SN DA neuron activity-pattern is complicated by their high vulnerability. We studied this activity and its control by dopamine, NCS-1, and glucose with extracellular multi-electrode array (MEA) recordings from midbrain slices of juvenile and adult mice. Our tailored MEA- and spike sorting-protocols allowed high throughput and long recording times. According to individual dopamine-responses, we identified two distinct SN cell-types, in similar frequency: dopamine-inhibited and dopamine-excited neurons. Dopamine-excited neurons were either silent in the absence of dopamine, or they displayed pacemaker-activities, similar to that of dopamine-inhibited neurons. Inhibition of pacemaker-activity by dopamine is typical for SN DA neurons, and it can undergo prominent desensitization. We show for adult mice, that the number of SN DA neurons with desensitized dopamine-inhibition was increased (~60–100%) by a knockout of NCS-1, or by prevention of NCS-1 binding to D2-autoreceptors, while time-course and degrees of desensitization were not altered. The number of neurons with desensitized D2-responses was also higher (~65%) at high glucose-levels (25 mM), compared to lower glucose (2.5 mM), while again desensitization-kinetics were unaltered. However, spontaneous firing-rates were significantly higher at high glucose-levels (~20%). Moreover, transient glucose-deprivation (1 mM) induced a fast and fully-reversible pacemaker frequency reduction. To directly address and quantify glucose-sensing properties of SN DA neurons, we continuously monitored their electrical activity, while altering extracellular glucose concentrations stepwise from 0.5 mM up to 25 mM. SN DA neurons were excited by glucose, with EC50 values ranging from 0.35 to 2.3 mM. In conclusion, we identified a novel, common subtype of dopamine-excited SN neurons, and a complex, joint regulation of dopamine-inhibited neurons by dopamine and glucose, within the range of physiological brain glucose-levels.
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Affiliation(s)
- Nadja Mannal
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | - Michael Fauler
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | | | - Birgit Liss
- Institute of Applied Physiology, University of Ulm, Ulm, Germany.,Linacre and New College, University of Oxford, Oxford, United Kingdom
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Dela Peña I, Shen G, Shi WX. Droxidopa alters dopamine neuron and prefrontal cortex activity and improves attention-deficit/hyperactivity disorder-like behaviors in rats. Eur J Pharmacol 2021; 892:173826. [PMID: 33347825 DOI: 10.1016/j.ejphar.2020.173826] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/11/2020] [Accepted: 12/16/2020] [Indexed: 12/15/2022]
Abstract
Finding alternative treatments for attention-deficit/hyperactivity disorder (ADHD) is crucial given the safety and efficacy problems of current ADHD medications. Droxidopa, also known as L-threo-dihydroxyphenylserine (L-DOPS), is a norepinephrine prodrug that enhances brain norepinephrine and dopamine levels. In this study, we used electrophysiological tests to examine effects of L-DOPS on the prefrontal cortex (PFC) and dopamine neurons in the ventral tegmental area. We also conducted behavioral tests to assess L-DOPS' effects on ADHD-like behaviors in rats. In chloral hydrate-anesthetized rats, PFC local field potentials oscillated between the active, depolarized UP state and the hyperpolarized DOWN state. Mimicking the effect of d-amphetamine, L-DOPS, given after the peripheral amino acid decarboxylase inhibitor, benserazide (BZ), increased the amount of time the PFC spent in the UP state, indicating an excitatory effect of L-DOPS on PFC neurons. Like d-amphetamine, L-DOPS also inhibited dopamine neurons, an effect significantly reversed by the D2-like receptor antagonist raclopride. In the behavioral tests, BZ + L-DOPS improved hyperactivity, inattention and impulsive action of the adolescent spontaneously hypertensive rat (SHR/NCrl), well-validated animal model of the combined type of ADHD. BZ + L-DOPS also reduced impulsive choice and impulsive action of Wistar rats, but did not ameliorate the inattentiveness of Wistar Kyoto rats (WKY/NCrl), proposed model of the ADHD-predominantly inattentive type. In conclusion, L-DOPS produced effects on the PFC and dopamine neurons characteristic of drugs used to treat ADHD. BZ + L-DOPS ameliorated ADHD-like behaviors in rats suggesting its potential as an alternative ADHD treatment.
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Affiliation(s)
- Ike Dela Peña
- Department of Pharmaceutical and Administrative Sciences, Loma Linda University School of Pharmacy, Loma Linda, CA, 92350, USA.
| | - Guofang Shen
- Department of Pharmaceutical and Administrative Sciences, Loma Linda University School of Pharmacy, Loma Linda, CA, 92350, USA
| | - Wei-Xing Shi
- Department of Pharmaceutical and Administrative Sciences, Loma Linda University School of Pharmacy, Loma Linda, CA, 92350, USA; Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, 92350, USA
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Therapeutic potential of targeting G protein-gated inwardly rectifying potassium (GIRK) channels in the central nervous system. Pharmacol Ther 2021; 223:107808. [PMID: 33476640 DOI: 10.1016/j.pharmthera.2021.107808] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/05/2021] [Indexed: 12/15/2022]
Abstract
G protein-gated inwardly rectifying potassium channels (Kir3/GirK) are important for maintaining resting membrane potential, cell excitability and inhibitory neurotransmission. Coupled to numerous G protein-coupled receptors (GPCRs), they mediate the effects of many neurotransmitters, neuromodulators and hormones contributing to the general homeostasis and particular synaptic plasticity processes, learning, memory and pain signaling. A growing number of behavioral and genetic studies suggest a critical role for the appropriate functioning of the central nervous system, as well as their involvement in many neurologic and psychiatric conditions, such as neurodegenerative diseases, mood disorders, attention deficit hyperactivity disorder, schizophrenia, epilepsy, alcoholism and drug addiction. Hence, GirK channels emerge as a very promising tool to be targeted in the current scenario where these conditions already are or will become a global public health problem. This review examines recent findings on the physiology, function, dysfunction, and pharmacology of GirK channels in the central nervous system and highlights the relevance of GirK channels as a worthful potential target to improve therapies for related diseases.
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McKendrick G, Sharma S, Sun D, Randall PA, Graziane NM. Acute and chronic bupropion treatment does not prevent morphine-induced conditioned place preference in mice. Eur J Pharmacol 2020; 889:173638. [PMID: 33039460 DOI: 10.1016/j.ejphar.2020.173638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/28/2020] [Accepted: 10/07/2020] [Indexed: 12/14/2022]
Abstract
A substantial barrier to the treatment of Opioid Use Disorder (OUD) is the elevated relapse rates in affected patients, and a significant contributor to these events of relapse is exposure to cues and contexts that are intensely associated with prior drug abuse. The neurotransmitter dopamine plays a key role in reward-related behaviors, and previous studies have illustrated that dopamine hypofunction in periods of abstinence serves to prompt drug craving and seeking. We hypothesized that restoration of dopaminergic signaling could attenuate drug-seeking behaviors. Therefore, we investigated whether use of an FDA-approved drug, bupropion, an inhibitor of the dopamine transporter (DAT), or a dopamine uptake inhibitor with high affinity for DAT, JHW 007, was able to decrease preference for a drug-paired context. In these experiments, mice underwent 5 days of non-contingent morphine (10 mg/kg) exposure in a conditioned place preference (CPP) paradigm. We found that systemic injection of bupropion (20 mg/kg, i. p.) or intracranial injection of JHW 007 into the nucleus accumbens shell did not prevent the expression of morphine CPP. We then investigated whether chronic bupropion treatment (via implanted osmotic pumps) would influence morphine CPP. We observed that chronic bupropion treatment for 21 days following morphine conditioning did not attenuate the prolonged preference for morphine-paired contexts. Overall, with our dose and paradigm, neither acute nor chronic bupropion diminishes morphine CPP. Continued studies should address FDA-approved medications and their potential for recovery in OUD patients.
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Affiliation(s)
- Greer McKendrick
- Neuroscience Graduate Program, Penn State College of Medicine, Hershey, PA 17033, USA; Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Sonakshi Sharma
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Dongxiao Sun
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Patrick A Randall
- Departments of Anesthesiology and Perioperative Medicine and Pharmacology, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Nicholas M Graziane
- Departments of Anesthesiology and Perioperative Medicine and Pharmacology, Penn State College of Medicine, Hershey, PA 17033, USA.
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Gao M, Der-Ghazarian TS, Li S, Qiu S, Neisewander JL, Wu J. Dual Effect of 5-HT 1B/1D Receptors on Dopamine Neurons in Ventral Tegmental Area: Implication for the Functional Switch After Chronic Cocaine Exposure. Biol Psychiatry 2020; 88:922-934. [PMID: 32172944 DOI: 10.1016/j.biopsych.2020.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/19/2019] [Accepted: 01/10/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Serotonin (5-HT) 1B/1D receptor (5-HT1B/1DR) agonists undergo an abstinence-induced switch in their effects on cocaine-related behaviors, which may involve changes in modulation of dopamine (DA) neurons in the ventral tegmental area (VTA). However, it is unclear how 5-HT1B/1DRs affect VTA DA neuronal function and whether modulation of these neurons mediates the abstinence-induced switch after chronic cocaine exposure. METHODS We examined the ability of 5-HT1B/1DRs to modulate D2 autoreceptors (D2ARs) and synaptic transmission in the VTA by slice recording and single unit recording in vivo in naïve mice and in mice with chronic cocaine treatment. RESULTS We report a bidirectional modulation of VTA DA neuronal firing through the interaction of VTA 5-HT1B/1DRs and D2ARs. In both VTA slices and the VTA of anesthetized mice, the 5-HT1B/1DR agonist CP94253 decreased DA neuronal firing rate and evoked excitatory postsynaptic currents to DA neurons in slice. Paradoxically, CP94253 decreased quinpirole-induced inhibition of DA neurons by reducing D2AR-mediated G protein-gated inwardly rectifying potassium current. This manifested decreased GABAA (gamma-aminobutyric acid A) receptor-mediated evoked inhibitory postsynaptic currents in slice, resulting in disinhibition of DA neurons, in opposition to the 5-HT1B/1DR-induced inhibition. This dual effect was verified in chronic cocaine-treated and mild stress-treated, male mice on days 1 and 20 posttreatment. CONCLUSIONS This study revealed dual effects of CP94253 on VTA DA neurons that are dependent on D2AR sensitivity, with anti-inhibition under normal D2AR sensitivity and inhibition under low D2AR sensitivity. These dual effects may underlie the ability of CP94253 to both enhance and inhibit cocaine-induced behaviors.
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Affiliation(s)
- Ming Gao
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ.
| | | | - Shuangtao Li
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ; Shantou University Medical College, Guangdong, Shantou, China
| | - Shenfeng Qiu
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ
| | | | - Jie Wu
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ; Shantou University Medical College, Guangdong, Shantou, China.
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Chen R, Ferris MJ, Wang S. Dopamine D2 autoreceptor interactome: Targeting the receptor complex as a strategy for treatment of substance use disorder. Pharmacol Ther 2020; 213:107583. [PMID: 32473160 PMCID: PMC7434700 DOI: 10.1016/j.pharmthera.2020.107583] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 05/11/2020] [Indexed: 02/06/2023]
Abstract
Dopamine D2 autoreceptors (D2ARs), located in somatodendritic and axon terminal compartments of dopamine (DA) neurons, function to provide a negative feedback regulatory control on DA neuron firing, DA synthesis, reuptake and release. Dysregulation of D2AR-mediated DA signaling is implicated in vulnerability to substance use disorder (SUD). Due to the extreme low abundance of D2ARs compared to postsynaptic D2 receptors (D2PRs) and the lack of experimental tools to differentiate the signaling of D2ARs from D2PRs, the regulation of D2ARs by drugs of abuse is poorly understood. The recent availability of conditional D2AR knockout mice and newly developed virus-mediated gene delivery approaches have provided means to specifically study the function of D2ARs at the molecular, cellular and behavioral levels. There is a growing revelation of novel mechanisms and new proteins that mediate D2AR activity, suggesting that D2ARs act cooperatively with an array of membrane and intracellular proteins to tightly control DA transmission. This review highlights D2AR-interacting partners including transporters, G-protein-coupled receptors, ion channels, intracellular signaling modulators, and protein kinases. The complexity of the D2AR interaction network illustrates the functional divergence of D2ARs. Pharmacological targeting of multiple D2AR-interacting partners may be more effective to restore disrupted DA homeostasis by drugs of abuse.
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Affiliation(s)
- Rong Chen
- Dept. of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States of America; Center for the Neurobiology of Addiction Treatment, Wake Forest School of Medicine, Winston Salem, NC 27157, United States of America.
| | - Mark J Ferris
- Dept. of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States of America; Center for the Neurobiology of Addiction Treatment, Wake Forest School of Medicine, Winston Salem, NC 27157, United States of America
| | - Shiyu Wang
- Dept. of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States of America
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Pérez‐Taboada I, Alberquilla S, Martín ED, Anand R, Vietti‐Michelina S, Tebeka NN, Cantley J, Cragg SJ, Moratalla R, Vallejo M. Diabetes Causes Dysfunctional Dopamine Neurotransmission Favoring Nigrostriatal Degeneration in Mice. Mov Disord 2020; 35:1636-1648. [PMID: 32666590 PMCID: PMC7818508 DOI: 10.1002/mds.28124] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/05/2020] [Accepted: 05/12/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Numerous studies indicate an association between neurodegenerative and metabolic diseases. Although still a matter of debate, growing evidence from epidemiological and animal studies indicate that preexisting diabetes increases the risk to develop Parkinson's disease. However, the mechanisms of such an association are unknown. OBJECTIVES We investigated whether diabetes alters striatal dopamine neurotransmission and assessed the vulnerability of nigrostriatal neurons to neurodegeneration. METHODS We used streptozotocin-treated and genetically diabetic db/db mice. Expression of oxidative stress and nigrostriatal neuronal markers and levels of dopamine and its metabolites were monitored. Dopamine release and uptake were assessed using fast-scan cyclic voltammetry. 6-Hydroxydopamine was unilaterally injected into the striatum using stereotaxic surgery. Motor performance was scored using specific tests. RESULTS Diabetes resulted in oxidative stress and decreased levels of dopamine and its metabolites in the striatum. Levels of proteins regulating dopamine release and uptake, including the dopamine transporter, the Girk2 potassium channel, the vesicular monoamine transporter 2, and the presynaptic vesicle protein synaptobrevin-2, were decreased in diabetic mice. Electrically evoked levels of extracellular dopamine in the striatum were enhanced, and altered dopamine uptake was observed. Striatal microinjections of a subthreshold dose of the neurotoxin 6-hydroxydopamine in diabetic mice, insufficient to cause motor alterations in nondiabetic animals, resulted in motor impairment, higher loss of striatal dopaminergic axons, and decreased neuronal cell bodies in the substantia nigra. CONCLUSIONS Our results indicate that diabetes promotes striatal oxidative stress, alters dopamine neurotransmission, and increases vulnerability to neurodegenerative damage leading to motor impairment. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Iara Pérez‐Taboada
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad Autónoma de MadridMadridSpain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas CIBERDEMMadridSpain
| | - Samuel Alberquilla
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC)MadridSpain
| | - Eduardo D. Martín
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC)MadridSpain
| | - Rishi Anand
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUnited Kingdom
| | | | - Nchimunya N. Tebeka
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUnited Kingdom
- Division of Systems MedicineUniversity of Dundee, Ninewells Hospital & Medical SchoolDundeeUnited Kingdom
| | - James Cantley
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUnited Kingdom
- Division of Systems MedicineUniversity of Dundee, Ninewells Hospital & Medical SchoolDundeeUnited Kingdom
| | - Stephanie J. Cragg
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUnited Kingdom
- Oxford Parkinson's Disease CentreUniversity of OxfordOxfordUnited Kingdom
| | - Rosario Moratalla
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC)MadridSpain
- CIBERNED, Instituto de Salud Carlos IIIMadridSpain
| | - Mario Vallejo
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad Autónoma de MadridMadridSpain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas CIBERDEMMadridSpain
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Wang Y, Bouabid S, Darvas M, Zhou FM. The antiparkinson drug ropinirole inhibits movement in a Parkinson's disease mouse model with residual dopamine neurons. Exp Neurol 2020; 333:113427. [PMID: 32735872 DOI: 10.1016/j.expneurol.2020.113427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 07/21/2020] [Accepted: 07/25/2020] [Indexed: 10/23/2022]
Abstract
The dopamine (DA) D2-like receptor (D2R) agonist ropinirole is often used for early and middle stage Parkinson's disease (PD). However, this D2-like agonism-based strategy has a complicating problem: D2-like agonism may activate D2 autoreceptors on the residual DA neurons in the PD brain, potentially inhibiting these residual DA neurons and motor function. We have examined this possibility by using systemic and local drug administration in transcription factor Pitx3 null mutant (Pitx3Null) mice that mimic the DA denervation in early and middle stage PD and in DA neuron tyrosine hydroxylase (TH) gene knockout (KO) mice that mimic the severe DA loss in late stage PD. We found that in Pitx3Null mice with residual DA neurons and normal mice with normal DA system, systemically injected ropinirole inhibited locomotion, whereas bilateral dorsal striatal-microinjected ropinirole stimulated movement in Pitx3Null mice; bilateral microinjection of ropinirole into the ventral tegmental area also inhibited movement in Pitx3Null mice; we further determined that ropinirole inhibited nigral DA neuron spike firing in WT mice. In contrast, both systemically and striatum-locally administered ropinirole increased movements in TH KO mice, but produced relatively more dyskinesia than L-dopa. Although requiring confirmation in non-human primates and PD patients, these data suggest that while activating D2-like receptors in striatal projection neurons and hence stimulating movements, D2-like agonists can inhibit residual DA neurons and cause akinesia when the residual DA neurons and motor functions are still substantial, and this motor-inhibitory effect disappears when almost all DA neurons are lost such as in late stage PD.
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Affiliation(s)
- Yuhan Wang
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee, Memphis, TN 38103, USA
| | - Safa Bouabid
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee, Memphis, TN 38103, USA
| | - Martin Darvas
- Department of Pathology, University of Washington, Seattle, WA 98104, USA
| | - Fu-Ming Zhou
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee, Memphis, TN 38103, USA.
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Chang X, Ma Z, Shi L, Xie J. Effects of ghrelin on the electrical activities of substantia nigra dopaminergic neurons treated with MPP .. Neurochem Int 2020; 138:104780. [PMID: 32569790 DOI: 10.1016/j.neuint.2020.104780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 05/19/2020] [Accepted: 05/30/2020] [Indexed: 12/17/2022]
Abstract
Ghrelin, a 28 amino acid brain-gut peptide, has attracted increasing attention for its neuroprotective effect in Parkinson's disease (PD). In view of the pivotal role of excitability of dopaminergic neurons in substantia nigra pars compacta (SNc) in the function of nigrostriatal system, it is of great significance to elucidate the regulation of electrical activity of dopaminergic neurons by ghrelin, especially in PD pathogenesis. In this study, we tackled this issue by probing the effects of ghrelin on the electrophysiological properties of dopaminergic neurons in acute application of Methyl-4-phenylpyridinium (MPP+), a potent parkinsonizing agent in primates and rodents, with whole cell patch clamp technique. We first observed that MPP+ (10, 20 and 50 μM) inhibited the spontaneous firing activity of dopaminergic neurons with dose-dependent and time-dependent properties. MPP+ also hyperpolarized the membrane potential, inhibited the evoked firing activity and reduced the amplitude of the inward rectification characteristic (Sag) in dopaminergic neurons. Importantly, ghrelin (100 nM) could improve the above effects of MPP+ on the electrical activities of dopaminergic neurons. The potential mechanism of this phenomenon may be that ghrelin upregulated hyperpolarization-activated cyclic nucleotide-gated channel current (Ih) to antagonize the inhibition of MPP+ on Ih, thereby improving the electrical activities of dopaminergic neurons.
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Affiliation(s)
- Xiaoli Chang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, School of Basic Medicine, Medical College of Qingdao University, Qingdao, 266071, China; Institute of Brain Science and Disease, Qingdao University, Qingdao, 266071, China; Institute of Acupuncture, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Zegang Ma
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, School of Basic Medicine, Medical College of Qingdao University, Qingdao, 266071, China; Institute of Brain Science and Disease, Qingdao University, Qingdao, 266071, China
| | - Limin Shi
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, School of Basic Medicine, Medical College of Qingdao University, Qingdao, 266071, China; Institute of Brain Science and Disease, Qingdao University, Qingdao, 266071, China.
| | - Junxia Xie
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, School of Basic Medicine, Medical College of Qingdao University, Qingdao, 266071, China; Institute of Brain Science and Disease, Qingdao University, Qingdao, 266071, China.
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Zizzo MG, Bellanca A, Amato A, Serio R. Opposite effects of dopamine on the mechanical activity of circular and longitudinal muscle of human colon. Neurogastroenterol Motil 2020; 32:e13811. [PMID: 32012410 DOI: 10.1111/nmo.13811] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 01/08/2020] [Accepted: 01/14/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Because dopamine (DA) has gained increasing evidence as modulator of gut motility, we aimed to characterize dopaminergic response in human colon, evaluating function and distribution of dopamine receptors in circular vs longitudinal muscle strips. METHODS Mechanical responses to DA and dopaminergic agonists on slow phasic contractions and on basal tone were examined in vitro as changes in isometric tension. RT-PCR was used to reveal the distribution of dopaminergic receptors. KEY RESULTS In spontaneous active circular muscle, DA induced an increase in the amplitude of slow phasic contractions and of the basal tone, via activation of D1-like receptors. DA contractile responses were insensitive to neural blockers or to atropine and inhibited by phospholipase C (PLC) pathway inhibitors. In precontracted circular muscle strips, DA, at the higher concentrations tested, caused a relaxant response via activation of D2-like receptors. In the longitudinal muscle, DA caused only muscular relaxation due to activation of D2-like receptors. DA relaxant responses were insensitive to neural blockers or to nitric oxide synthase inhibitor and reduced by a wide-spectrum K+ channel blockers. Transcripts encoding for all the dopaminergic receptor subtypes was observed in both circular and longitudinal preparations. CONCLUSIONS AND INFERENCES Dopamine is able to modulate contractile activity of the human colon. In the circular muscle layer, DA induces mainly muscular contraction activating non-neural D1-like receptors, coupled to PLC/IP3 pathway. In the longitudinal muscle layer, DA induces muscular relaxation acting on non-neural D2-like receptors leading to the increase in K+ conductance.
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Affiliation(s)
- Maria Grazia Zizzo
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Palermo, Italy.,ATeN (Advanced Technologies Network) Center, University of Palermo, Palermo, Italy
| | - Annalisa Bellanca
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Palermo, Italy
| | - Antonella Amato
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Palermo, Italy
| | - Rosa Serio
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Palermo, Italy
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Martin TA, Smith HR, Luessen DJ, Chen R, Porrino LJ. Functional brain activity is globally elevated by dopamine D2 receptor knockdown in the ventral tegmental area. Brain Res 2020; 1727:146552. [PMID: 31726041 PMCID: PMC6941665 DOI: 10.1016/j.brainres.2019.146552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/07/2019] [Accepted: 11/10/2019] [Indexed: 12/14/2022]
Abstract
The mesocorticolimbic system is comprised of dopaminergic neurons in the ventral tegmental area (VTA) and their projection targets in the ventral striatum, amygdala, prefrontal cortex, and hippocampus, among others. Regulation of dopamine transmission within this system is achieved in part through a negative feedback mechanism via dopamine D2 autoreceptors located on somatodendrites and terminals of VTA dopaminergic neurons. Dysregulation of this mechanism has been implicated in addiction and other psychiatric disorders, although the biological bases for these associations are unclear. In order to elucidate the functional consequences of VTA D2 receptor dysregulation, this study investigated alterations in local cerebral glucose utilization throughout the brain following Drd2 knockdown in the VTA. Male Sprague-Dawley rats received bilateral injections of lentivirus encoding shRNAs against the rat dopamine D2 receptor, scrambled shRNA or phosphate buffered saline. The autoradiographic 2-[14C]deoxyglucose metabolic mapping procedure was conducted 22 days post-infection. Brains were sectioned for autoradiography and glucose utilization was measured across distinct regions throughout the brain. Local cerebral glucose utilization was found to be elevated in the Drd2 knockdown group as compared to control groups. These greater levels of metabolic activity following Drd2 knockdown in the VTA were observed not only in the mesocorticolimbic system and associated dopamine pathways, but also in a global pattern that included many areas with far less concentrated VTA dopamine inputs. This suggests that even a partial Drd2 deletion in the VTA can have widespread consequences and impact information flow in diverse networks that process sensory, cognitive, motor and emotional information.
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Affiliation(s)
- Tamriage A Martin
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Hilary R Smith
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Deborah J Luessen
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Rong Chen
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Linda J Porrino
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
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Furukawa E, da Costa RQM, Bado P, Hoefle S, Vigne P, Monteiro M, Wickens JR, Moll J, Tripp G, Mattos P. Methylphenidate modifies reward cue responses in adults with ADHD: An fMRI study. Neuropharmacology 2020; 162:107833. [DOI: 10.1016/j.neuropharm.2019.107833] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 01/01/2023]
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Dopamine Evokes a Trace Amine Receptor-dependent Inward Current that is Regulated by AMP Kinase in Substantia Nigra Dopamine Neurons. Neuroscience 2019; 427:77-91. [PMID: 31883822 DOI: 10.1016/j.neuroscience.2019.11.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/21/2019] [Accepted: 11/26/2019] [Indexed: 12/27/2022]
Abstract
We reported recently that activators of AMP-activated protein kinase (AMPK) slow the rundown of current evoked by the D2 autoreceptor agonist quinpirole in rat substantia nigra compacta (SNC) dopamine neurons. The present study examined the effect of AMPK on current generated by dopamine, which unlike quinpirole, is a substrate for the dopamine transporter (DAT). Using whole-cell patch-clamp, we constructed current-voltage (I-V) plots while superfusing brain slices with dopamine (100 μM) for 25 min. Two minutes after starting superfusion, dopamine evoked a peak current with an average slope conductance of 0.97 nS and an estimated reversal potential (Erev) of -113 mV, which is near that expected for K+. But after 10 min of superfusion, dopamine-evoked currents had shifted to more depolarized values with a slope conductance of 0.64 nS and an Erev of -83 mV. This inward shift in current was completely blocked by the DAT inhibitor GBR12935. However, an AMPK blocking agent (dorsomorphin) permitted the emergence of inward current despite the continued presence of the DAT inhibitor. When D2 autoreceptors were blocked by sulpiride, I-V plots showed that dopamine evoked an inward current with an estimated slope conductance of 0.45 nS with an Erev of -57 mV. Moreover, this inward current was completely blocked by the trace amine-associated receptor 1 (TAAR1) antagonist EPPTB. These results suggest that dopamine activates a TAAR1-dependent non-selective cation current that is regulated by AMPK.
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40
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He D, Lasek AW. Anaplastic Lymphoma Kinase Regulates Internalization of the Dopamine D2 Receptor. Mol Pharmacol 2019; 97:123-131. [PMID: 31734646 DOI: 10.1124/mol.119.117473] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 11/11/2019] [Indexed: 12/16/2022] Open
Abstract
The dopamine D2 receptor (D2R) is a G protein-coupled receptor (GPCR) expressed in regions of the brain that control motor function, cognition, and motivation. As a result, D2R is involved in the pathophysiology of disorders such as schizophrenia and drug addiction. Understanding the signaling pathways activated by D2R is crucial to finding new therapeutic targets for these disorders. D2R stimulation by its agonist, dopamine, causes desensitization and internalization of the receptor. A previous study found that inhibitors of the receptor tyrosine kinase anaplastic lymphoma kinase (ALK) blocked D2R desensitization in neurons in the ventral tegmental area of the brain. In the present study, using a cell-based system, we investigated whether ALK regulates D2R internalization. The ALK inhibitor alectinib completely inhibited dopamine-induced D2R internalization. Since GPCRs can transactivate receptor tyrosine kinases, we also examined if D2R stimulation activated ALK signaling. ALK phosphorylation increased by almost 2-fold after dopamine treatment and ALK coimmunoprecipitated with D2R. To identify the signaling pathways downstream of ALK that might regulate D2R internalization, we used pharmacological inhibitors of proteins activated by ALK signaling. Protein kinase Cγ was activated by dopamine in an ALK-dependent manner, and a protein kinase C inhibitor completely blocked dopamine-induced D2R internalization. Taken together, these results identify ALK as a receptor tyrosine kinase transactivated by D2R that promotes its internalization, possibly through activation of protein kinase C. ALK inhibitors could be useful in enhancing D2R signaling. SIGNIFICANCE STATEMENT: Receptor internalization is a mechanism by which receptors are desensitized. In this study we found that agonist-induced internalization of the dopamine D2 receptor is regulated by the receptor tyrosine kinase ALK. ALK was also transactivated by and associated with dopamine D2 receptor. Dopamine activated protein kinase C in an ALK-dependent manner and a PKC inhibitor blocked dopamine D2 receptor internalization. These results indicate that ALK regulates dopamine D2 receptor trafficking, which has implications for psychiatric disorders involving dysregulated dopamine signaling.
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Affiliation(s)
- Donghong He
- Center for Alcohol Research in Epigenetics and Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
| | - Amy W Lasek
- Center for Alcohol Research in Epigenetics and Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
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41
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Lebowitz JJ, Khoshbouei H. Heterogeneity of dopamine release sites in health and degeneration. Neurobiol Dis 2019; 134:104633. [PMID: 31698055 DOI: 10.1016/j.nbd.2019.104633] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/12/2019] [Accepted: 10/02/2019] [Indexed: 02/06/2023] Open
Abstract
Despite comprising only ~ 0.001% of all neurons in the human brain, ventral midbrain dopamine neurons exert a profound influence on human behavior and cognition. As a neuromodulator, dopamine selectively inhibits or enhances synaptic signaling to coordinate neural output for action, attention, and affect. Humans invariably lose brain dopamine during aging, and this can be exacerbated in disease states such as Parkinson's Disease. Further, it is well established in multiple disease states that cell loss is selective for a subset of highly sensitive neurons within the nigrostriatal dopamine tract. Regional differences in dopamine tone are regulated pre-synaptically, with subcircuits of projecting dopamine neurons exhibiting distinct molecular and physiological signatures. Specifically, proteins at dopamine release sites that synthesize and package cytosolic dopamine, modulate its release and reuptake, and alter neuronal excitability show regional differences that provide linkages to the observed sensitivity to neurodegeneration. The aim of this review is to outline the major components of dopamine homeostasis at neurotransmitter release sites and describe the regional differences most relevant to understanding why some, but not all, dopamine neurons exhibit heightened vulnerability to neurodegeneration.
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Affiliation(s)
- Joseph J Lebowitz
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Habibeh Khoshbouei
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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42
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Fuller JA, Burrell MH, Yee AG, Liyanagama K, Lipski J, Wickens JR, Hyland BI. Role of homeostatic feedback mechanisms in modulating methylphenidate actions on phasic dopamine signaling in the striatum of awake behaving rats. Prog Neurobiol 2019; 182:101681. [DOI: 10.1016/j.pneurobio.2019.101681] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/25/2019] [Accepted: 08/06/2019] [Indexed: 12/13/2022]
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43
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AMP-activated protein kinase slows D2 dopamine autoreceptor desensitization in substantia nigra neurons. Neuropharmacology 2019; 158:107705. [PMID: 31301335 DOI: 10.1016/j.neuropharm.2019.107705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 12/14/2022]
Abstract
Dopamine neurons in the substantia nigra zona compacta (SNC) are well known to express D2 receptors. When dopamine is released from somatodendritic sites, activation of D2 autoreceptors suppresses dopamine neuronal activity through activation of G protein-coupled K+ channels. AMP-activated protein kinase (AMPK) is a master enzyme that acts in somatic tissues to suppress energy expenditure and encourage energy production. We hypothesize that AMPK may also conserve energy in central neurons by reducing desensitization of D2 autoreceptors. We used whole-cell patch-clamp recordings to study the effects of AMPK activators and inhibitors on D2 autoreceptor-mediated current in SNC neurons in midbrain slices from rat pups (11-23 days post-natal). Slices were superfused with 100 μM dopamine or 30 μM quinpirole for 25 min, which evoked outward currents that decayed slowly over time. Although the AMPK activators A769662 and ZLN024 significantly slowed rundown of dopamine-evoked current, slowing of quinpirole-evoked current required the presence of a D1-like agonist (SKF38393). Moreover, the D1-like agonist also slowed the rundown of quinpirole-induced current even in the absence of an AMPK activator. Pharmacological antagonist experiments showed that the D1-like agonist effect required activation of either protein kinase A (PKA) or exchange protein directly activated by cAMP 2 (Epac2) pathways. In contrast, the effect of AMPK on rundown of current evoked by quinpirole plus SKF38393 required PKA but not Epac2. We conclude that AMPK slows D2 autoreceptor desensitization by augmenting the effect of D1-like receptors.
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The striatal-enriched protein Rhes is a critical modulator of cocaine-induced molecular and behavioral responses. Sci Rep 2019; 9:15294. [PMID: 31653935 PMCID: PMC6814836 DOI: 10.1038/s41598-019-51839-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/09/2019] [Indexed: 12/31/2022] Open
Abstract
Previous evidence pointed out a role for the striatal-enriched protein Rhes in modulating dopaminergic transmission. Based on the knowledge that cocaine induces both addiction and motor stimulation, through its ability to enhance dopaminergic signaling in the corpus striatum, we have now explored the involvement of Rhes in the effects associated with this psychostimulant. Our behavioral data showed that a lack of Rhes in knockout animals caused profound alterations in motor stimulation following cocaine exposure, eliciting a significant leftward shift in the dose-response curve and triggering a dramatic hyperactivity. We also found that Rhes modulated either short- or long-term motor sensitization induced by cocaine, since lack of this protein prevents both of them in mutants. Consistent with this in vivo observation, we found that lack of Rhes in mice caused a greater increase in striatal cocaine-dependent D1R/cAMP/PKA signaling, along with considerable enhancement of Arc, zif268, and Homer1 mRNA expression. We also documented that lack of Rhes in mice produced cocaine-related striatal alterations in proteomic profiling, with a differential expression of proteins clustering in calcium homeostasis and cytoskeletal protein binding categories. Despite dramatic striatal alterations associated to cocaine exposure, our data did not reveal any significant changes in midbrain dopaminergic neurons as a lack of Rhes did not affect: (i) DAT activity; (ii) D2R-dependent regulation of GIRK; and (iii) D2R-dependent regulation of dopamine release. Collectively, our results strengthen the view that Rhes acts as a pivotal physiological “molecular brake” for striatal dopaminergic system overactivation induced by psychostimulants, thus making this protein of interest in regulating the molecular mechanism underpinning cocaine-dependent motor stimulatory effects.
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45
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Yadav RK, Khanday MA, Mallick BN. Interplay of dopamine and GABA in substantia nigra for the regulation of rapid eye movement sleep in rats. Behav Brain Res 2019; 376:112169. [PMID: 31442548 DOI: 10.1016/j.bbr.2019.112169] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 08/15/2019] [Accepted: 08/19/2019] [Indexed: 01/05/2023]
Abstract
Substantia nigra (SN) is rich in dopamine (DA)-ergic and GABA-ergic neurons, which project to and receive inputs from locus coeruleus (LC) and pedunculo-pontine tegmentum (PPT) possessing REM-OFF and REM-ON neurons, respectively. Loss of DA-ergic neurons and disturbed REM sleep (REMS) are associated with Parkinson's disease, depression and REMS behavior disorder. GABA-ergic projections from SN act pre-synaptically on the noradrenaline (NA)-ergic terminals coming from the LC-REM-OFF neurons onto the REM-ON neurons in PPT and play a critical role in initiating REMS. However, it was unknown how SN neurons get activated and whether the SN-DA-ergic neurons interact with the SN-GABA-ergic neurons for REMS regulation. In freely moving chronically prepared rats, neurons in SN (bilateral) were stimulated by local microinjection of Glutamate (Glut), sparing the fibers of passage, in the presence and absence of i.p. Haloperidol (Hal, DA-antagonist). In other sets, either Hal or Bicuculine (Bic, GABA-antagonist) alone or simultaneously was microinjected bilaterally into the SN and the effects on sleep-wakefulness were recorded. We observed that Glut in SN significantly increased REMS, which was prevented by Hal. REMS was decreased and increased by Hal and Bic, respectively; while their co-injection neutralized (ineffective) the individual effects. Combining these findings with previous reports suggest that the SN-DA-ergic neurons act on the SN-GABA-ergic to regulate REMS. The results advance our understanding of the neuro-anatomo-chemical connections and pharmaco-physiological regulation of REMS in health and diseases.
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46
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Chang X, Wang J, Jiang H, Shi L, Xie J. Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: An Emerging Role in Neurodegenerative Diseases. Front Mol Neurosci 2019; 12:141. [PMID: 31231190 PMCID: PMC6560157 DOI: 10.3389/fnmol.2019.00141] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 05/13/2019] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases such as Parkinson’s disease (PD), Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), and spinal muscular atrophy (SMA) are chronic, progressive, and age-associated neurological disorders characterized by neuronal deterioration in specific brain regions. Although the specific pathological mechanisms underlying these disorders have remained elusive, ion channel dysfunction has become increasingly accepted as a potential mechanism for neurodegenerative diseases. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are encoded by the HCN1-4 gene family and conduct the hyperpolarization-activated current (Ih). These channels play important roles in modulating cellular excitability, rhythmic activity, dendritic integration, and synaptic transmission. In the present review, we first provide a comprehensive picture of the role of HCN channels in PD by summarizing their role in the regulation of neuronal activity in PD-related brain regions. Dysfunction of Ih may participate in 1-methyl-4-phenylpyridinium (MPP+)-induced toxicity and represent a pathogenic mechanism in PD. Given current reports of the critical role of HCN channels in neuroinflammation and depression, we also discussed the putative contribution of HCN channels in inflammatory processes and non-motor symptoms in PD. In the second section, we summarize how HCN channels regulate the formation of β-amyloid peptide in AD and the role of these channels in learning and memory. Finally, we briefly discuss the effects of HCN channels in ALS and SMA based on existing discoveries.
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Affiliation(s)
- Xiaoli Chang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China.,Institute of Brain Science and Disease, Qingdao University, Qingdao, China
| | - Jun Wang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China.,Institute of Brain Science and Disease, Qingdao University, Qingdao, China
| | - Hong Jiang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China.,Institute of Brain Science and Disease, Qingdao University, Qingdao, China
| | - Limin Shi
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China.,Institute of Brain Science and Disease, Qingdao University, Qingdao, China
| | - Junxia Xie
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China.,Institute of Brain Science and Disease, Qingdao University, Qingdao, China
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47
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West KS, Lu C, Olson DP, Roseberry AG. Alpha-melanocyte stimulating hormone increases the activity of melanocortin-3 receptor-expressing neurons in the ventral tegmental area. J Physiol 2019; 597:3217-3232. [PMID: 31054267 DOI: 10.1113/jp277193] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 04/19/2019] [Indexed: 01/12/2023] Open
Abstract
KEY POINTS Alpha-melanocyte stimulating hormone (α-MSH) is an anorexigenic peptide. Injection of the α-MSH analog MTII into the ventral tegmental area (VTA) decreases food and sucrose intake and food reward. Melanocortin-3 receptors (MC3R) are highly expressed in the VTA, suggesting that the effects of intra-VTA α-MSH may be mediated by α-MSH changing the activity of MC3R-expressing VTA neurons. α-MSH increased the firing rate of MC3R VTA neurons in acute brain slices from mice, although it did not affect the firing rate of non-MC3R VTA neurons. The α-MSH induced increase in MC3R neuron firing rate is probably activity-dependent, and was independent of fast synaptic transmission and intracellular Ca2+ levels. These results help us to better understand how α-MSH acts in the VTA to affect feeding and other dopamine-dependent behaviours. ABSTRACT The mesocorticolimbic dopamine system, the brain's reward system, regulates multiple behaviours, including food intake and food reward. There is substantial evidence that the melanocortin system of the hypothalamus, an important neural circuit controlling feeding and body weight, interacts with the mesocorticolimbic dopamine system to affect feeding, food reward and body weight. For example, melanocortin-3 receptors (MC3Rs) are expressed in the ventral tegmental area (VTA) and our laboratory previously showed that intra-VTA injection of the MC3R agonist, MTII, decreases home-cage food intake and operant responding for sucrose pellets. However, the cellular mechanisms underlying the effects of intra-VTA alpha-melanocyte stimulating hormone (α-MSH) on feeding and food reward are unknown. To determine how α-MSH acts in the VTA to affect feeding, we performed electrophysiological recordings in acute brain slices from mice expressing enhanced yellow fluorescent protein in MC3R neurons to test how α-MSH affects the activity of VTA MC3R neurons. α-MSH significantly increased the firing rate of VTA MC3R neurons without altering the activity of non-MC3R expressing VTA neurons. In addition, the α-MSH-induced increase in MC3R neuron activity was independent of fast synaptic transmission and intracellular Ca2+ levels. Finally, we show that the effect of α-MSH on MC3R neuron firing rate is probably activity-dependent. Overall, these studies provide an important advancement in the understanding of how α-MSH acts in the VTA to affect feeding and food reward.
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Affiliation(s)
| | - Chunxia Lu
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - David P Olson
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Aaron G Roseberry
- Department of Biology.,Neuroscience Institute, , Georgia State University, Atlanta, GA, USA
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48
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Bizzarri BM, Botta L, Aversa D, Mercuri NB, Poli G, Barbieri A, Berretta N, Saladino R. L-DOPA-quinone Mediated Recovery from GIRK Channel Firing Inhibition in Dopaminergic Neurons. ACS Med Chem Lett 2019; 10:431-436. [PMID: 30996775 DOI: 10.1021/acsmedchemlett.8b00477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/09/2019] [Indexed: 01/07/2023] Open
Abstract
The oxidative degeneration of dopamine-releasing (DAergic) neurons in the substantia nigra pars compacta (SNc) has attracted much interest in preclinical research, due to its involvement in Parkinson's disease manifestations. Evidence exists on the participation of quinone derivatives in mitochondrial dysfunction, alpha synuclein protein aggregation, and protein degradation. With the aim to investigate the role of L-DOPA-quinone in DAergic neuron functions, we synthesized L-DOPA-quinone by use of 2-iodoxybenzoic acid and measured its activity in recovery from dopamine-mediated firing inhibition of SNc neurons. Noteworthy, L-DOPA-quinone counteracts firing inhibition in SNc DAergic neurons caused by GIRK opening. A possible mechanism to explain the effect of L-DOPA-quinone on GIRK channel has been proposed by computational models. Overall, the study showed the possibility that L-DOPA-quinone stabilizes GIRK in a preopen conformation through formation of a covalent adduct with cysteine-65 on the GIRK2 subunit of the protein.
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Affiliation(s)
- Bruno M. Bizzarri
- Dipartimento di Scienze Ecologiche e Biologiche, Università della Tuscia, Via S. C. De Lellis 44, 01100 Viterbo, Italy
| | - Lorenzo Botta
- Dipartimento di Scienze Ecologiche e Biologiche, Università della Tuscia, Via S. C. De Lellis 44, 01100 Viterbo, Italy
| | - Daniela Aversa
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306/354, 00142 Rome, Italy
| | - Nicola B. Mercuri
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306/354, 00142 Rome, Italy
- Dipartimento di Medicina dei Sistemi, Università di Roma Tor Vergata, Via Montpellier, 1, 00133 Rome, Italy
| | - Giulio Poli
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli studi di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Alessandro Barbieri
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli studi di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Nicola Berretta
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306/354, 00142 Rome, Italy
| | - Raffaele Saladino
- Dipartimento di Scienze Ecologiche e Biologiche, Università della Tuscia, Via S. C. De Lellis 44, 01100 Viterbo, Italy
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Tomagra G, Picollo F, Battiato A, Picconi B, De Marchis S, Pasquarelli A, Olivero P, Marcantoni A, Calabresi P, Carbone E, Carabelli V. Quantal Release of Dopamine and Action Potential Firing Detected in Midbrain Neurons by Multifunctional Diamond-Based Microarrays. Front Neurosci 2019; 13:288. [PMID: 31024230 PMCID: PMC6465646 DOI: 10.3389/fnins.2019.00288] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/11/2019] [Indexed: 12/20/2022] Open
Abstract
Micro-Graphitic Single Crystal Diamond Multi Electrode Arrays (μG-SCD-MEAs) have so far been used as amperometric sensors to detect catecholamines from chromaffin cells and adrenal gland slices. Besides having time resolution and sensitivity that are comparable with carbon fiber electrodes, that represent the gold standard for amperometry, μG-SCD-MEAs also have the advantages of simultaneous multisite detection, high biocompatibility and implementation of amperometric/potentiometric protocols, aimed at monitoring exocytotic events and neuronal excitability. In order to adapt diamond technology to record neuronal activity, the μG-SCD-MEAs in this work have been interfaced with cultured midbrain neurons to detect electrical activity as well as quantal release of dopamine (DA). μG-SCD-MEAs are based on graphitic sensing electrodes that are embedded into the diamond matrix and are fabricated using MeV ion beam lithography. Two geometries have been adopted, with 4 × 4 and 8 × 8 microelectrodes (20 μm × 3.5 μm exposed area, 200 μm spacing). In the amperometric configuration, the 4 × 4 μG-SCD-MEAs resolved quantal exocytosis from midbrain dopaminergic neurons. KCl-stimulated DA release occurred as amperometric spikes of 15 pA amplitude and 0.5 ms half-width, at a mean frequency of 0.4 Hz. When used as potentiometric multiarrays, the 8 × 8 μG-SCD-MEAs detected the spontaneous firing activity of midbrain neurons. Extracellularly recorded action potentials (APs) had mean amplitude of ∼-50 μV and occurred at a mean firing frequency of 0.7 Hz in 67% of neurons, while the remaining fired at 6.8 Hz. Comparable findings were observed using conventional MEAs (0.9 and 6.4 Hz, respectively). To test the reliability of potentiometric recordings with μG-SCD-MEAs, the D2-autoreceptor modulation of firing was investigated by applying levodopa (L-DOPA, 20 μM), and comparing μG-SCD-MEAs, conventional MEAs and current-clamp recordings. In all cases, L-DOPA reduced the spontaneous spiking activity in most neurons by 70%, while the D2-antagonist sulpiride reversed this effect. Cell firing inhibition was generally associated with increased APs amplitude. A minority of neurons was either insensitive to, or potentiated by L-DOPA, suggesting that AP recordings originate from different midbrain neuronal subpopulations and reveal different modulatory pathways. Our data demonstrate, for the first time, that μG-SCD-MEAs are multi-functional biosensors suitable to resolve real-time DA release and AP firing in in vitro neuronal networks.
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Affiliation(s)
- Giulia Tomagra
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Federico Picollo
- Department of Physics and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy.,Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Alfio Battiato
- Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Barbara Picconi
- Experimental Neurophysiology Laboratory, IRCCS San Raffaele Pisana, University San Raffaele, Rome, Italy.,University San Raffaele, Rome, Italy
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology and "NICO" Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Turin, Italy
| | | | - Paolo Olivero
- Department of Physics and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy.,Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Andrea Marcantoni
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Paolo Calabresi
- Neurological Clinic, Department of Medicine, Hospital Santa Maria della Misericordia, University of Perugia, Perugia, Italy
| | - Emilio Carbone
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Valentina Carabelli
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
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Piccart E, Tschumi CW, Beckstead MJ. Acute and subchronic PCP attenuate D2 autoreceptor signaling in substantia nigra dopamine neurons. Eur Neuropsychopharmacol 2019; 29:444-449. [PMID: 30686631 PMCID: PMC6421099 DOI: 10.1016/j.euroneuro.2019.01.108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/09/2019] [Accepted: 01/14/2019] [Indexed: 11/17/2022]
Abstract
Phencyclidine (PCP) administration is commonly used to model schizophrenia in laboratory animals. While PCP is well-characterized as an antagonist of glutamate-sensitive N-methyl-D-aspartate (NMDA) receptors, its effects on dopamine signaling are not well understood. Here we used whole-cell and cell-attached patch-clamp electrophysiology of substantia nigra dopamine neurons to determine the effects of acute and subchronic PCP exposure on both dopamine D2 autoreceptor-mediated currents and burst firing evoked by glutamate receptor activation. Acute PCP affected D2 autoreceptor-mediated currents through two apparently distinct mechanisms: a low-concentration dopamine transporter (DAT) inhibition and a high-concentration potassium (GIRK) channel inhibition. Subchronic administration of PCP (5 mg/kg, i.p., every 12 h for 7 days) decreased sensitivity to low dopamine concentrations, and also enhanced evoked burst firing of dopamine neurons. These findings suggest the effects of PCP on dopaminergic signaling in the midbrain could enhance burst firing and contribute to the development of schizophreniform behavior.
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Affiliation(s)
| | - Christopher W Tschumi
- Oklahoma Medical Research Foundation, Aging & Metabolism Research Program, Oklahoma City, OK 73104, USA; University of Texas Health, San Antonio, Department of Cellular & Integrative Physiology, San Antonio, TX 78228, USA
| | - Michael J Beckstead
- Oklahoma Medical Research Foundation, Aging & Metabolism Research Program, Oklahoma City, OK 73104, USA; University of Texas Health, San Antonio, Department of Cellular & Integrative Physiology, San Antonio, TX 78228, USA.
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