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Effects of monotherapy with a monoamine oxidase B inhibitor on motor symptoms in Parkinson's disease are dependent on frontal function. Neurol Sci 2023; 44:913-918. [PMID: 36376554 DOI: 10.1007/s10072-022-06499-6] [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: 09/30/2022] [Accepted: 11/05/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Monotherapy with monoamine oxidase B (MAO-B) inhibitors enhances the level of endogenous dopamine in treatment for Parkinson's disease (PD) and provides some benefits. Certain neuropsychiatric functions are also regulated by central dopaminergic activity. AIM To investigate the relationship of the efficacy of monotherapy with MAO-B inhibitors on motor symptoms in PD with baseline cognitive function. PATIENTS AND METHODS Outcomes were examined for 27 consecutive drug-naïve PD patients who received initial treatment with a MAO-B inhibitor (selegiline: 11, rasagiline: 16). Selegiline was titrated to an optimal dose. The dose of rasagiline was fixed at 1 mg/day. Motor symptoms were assessed using the Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III before treatment and after the efficacy reached a plateau within 19 weeks after drug initiation, and the % improvement in motor symptoms was calculated. Pre-treatment cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) and Frontal Assessment Battery (FAB). Correlations of % improvement in motor symptoms and baseline cognitive assessments were examined using Spearman correlation coefficients and multiple regression analysis. RESULTS In all patients, the mean % improvement in motor symptoms was 46.5% (range 0-83.3%). Spearman correlation coefficients showed the % improvement in motor symptoms was correlated with FAB (r = 0.631, p < 0.001). In multiple regression analysis with patient background factors as independent variables, only FAB was associated with improvement in motor symptoms in the MAO-B group. CONCLUSION Better FAB scores predict a significant improvement in motor symptoms with treatment with MAO-B inhibitors, suggesting high activity of endogenous dopamine.
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Hettiarachchi P, Niyangoda SS, Jarosova R, Johnson MA. Dopamine Release Impairments Accompany Locomotor and Cognitive Deficiencies in Rotenone-Treated Parkinson's Disease Model Zebrafish. Chem Res Toxicol 2022; 35:1974-1982. [PMID: 36178476 PMCID: PMC10127151 DOI: 10.1021/acs.chemrestox.2c00150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In this work, we carried out neurochemical and behavioral analysis of zebrafish (Danio rerio) treated with rotenone, an agent used to chemically induce a syndrome resembling Parkinson's disease (PD). Dopamine release, measured with fast-scan cyclic voltammetry (FSCV) at carbon-fiber electrodes in acutely harvested whole brains, was about 30% of that found in controls. Uptake, represented by the first order rate constant (k) and the half-life (t1/2) determined by nonlinear regression modeling of the stimulated release plots, was also diminished. Behavioral analysis revealed that rotenone treatment increased the time required for zebrafish to reach a reward within a maze by more than 50% and caused fish to select the wrong pathway, suggesting that latent learning was impaired. Additionally, zebrafish treated with rotenone suffered from diminished locomotor activity, swimming shorter distances with lower mean velocity and acceleration. Thus, the neurochemical and behavioral approaches, as applied, were able to resolve rotenone-induced differences in key parameters. This approach may be effective for screening therapies in this and other models of neurodegeneration.
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Affiliation(s)
- Piyanka Hettiarachchi
- Department of Chemistry and R.N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, Kansas 66045
| | - Sayuri S. Niyangoda
- Department of Chemistry and R.N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, Kansas 66045
| | - Romana Jarosova
- Department of Chemistry and R.N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, Kansas 66045
- Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Charles University, Prague 2, Czech Republic 12843
| | - Michael A. Johnson
- Department of Chemistry and R.N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, Kansas 66045
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Grinevich VP, Zakirov AN, Berseneva UV, Gerasimova EV, Gainetdinov RR, Budygin EA. Applying a Fast-Scan Cyclic Voltammetry to Explore Dopamine Dynamics in Animal Models of Neuropsychiatric Disorders. Cells 2022; 11:cells11091533. [PMID: 35563838 PMCID: PMC9100021 DOI: 10.3390/cells11091533] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 02/07/2023] Open
Abstract
Progress in the development of technologies for the real-time monitoring of neurotransmitter dynamics has provided researchers with effective tools for the exploration of etiology and molecular mechanisms of neuropsychiatric disorders. One of these powerful tools is fast-scan cyclic voltammetry (FSCV), a technique which has progressively been used in animal models of diverse pathological conditions associated with alterations in dopamine transmission. Indeed, for several decades FSCV studies have provided substantial insights into our understanding of the role of abnormal dopaminergic transmission in pathogenetic mechanisms of drug and alcohol addiction, Parkinson’s disease, schizophrenia, etc. Here we review the applications of FSCV to research neuropsychiatric disorders with particular attention to recent technological advances.
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Affiliation(s)
- Vladimir P. Grinevich
- Department of Neurobiology, Sirius University, 1 Olympic Ave., Sirius, Sochi 353340, Russia; (V.P.G.); (A.N.Z.); (U.V.B.); (E.V.G.); (R.R.G.)
| | - Amir N. Zakirov
- Department of Neurobiology, Sirius University, 1 Olympic Ave., Sirius, Sochi 353340, Russia; (V.P.G.); (A.N.Z.); (U.V.B.); (E.V.G.); (R.R.G.)
| | - Uliana V. Berseneva
- Department of Neurobiology, Sirius University, 1 Olympic Ave., Sirius, Sochi 353340, Russia; (V.P.G.); (A.N.Z.); (U.V.B.); (E.V.G.); (R.R.G.)
| | - Elena V. Gerasimova
- Department of Neurobiology, Sirius University, 1 Olympic Ave., Sirius, Sochi 353340, Russia; (V.P.G.); (A.N.Z.); (U.V.B.); (E.V.G.); (R.R.G.)
| | - Raul R. Gainetdinov
- Department of Neurobiology, Sirius University, 1 Olympic Ave., Sirius, Sochi 353340, Russia; (V.P.G.); (A.N.Z.); (U.V.B.); (E.V.G.); (R.R.G.)
- Institute of Translational Biomedicine and St. Petersburg State University Hospital, St. Petersburg State University, Universitetskaya Emb. 7-9, St. Petersburg 199034, Russia
| | - Evgeny A. Budygin
- Department of Neurobiology, Sirius University, 1 Olympic Ave., Sirius, Sochi 353340, Russia; (V.P.G.); (A.N.Z.); (U.V.B.); (E.V.G.); (R.R.G.)
- Correspondence:
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Holmes J, Witt CE, Keen D, Buchanan AM, Batey L, Hersey M, Hashemi P. Glutamate Electropolymerization on Carbon Increases Analytical Sensitivity to Dopamine and Serotonin: An Auspicious In Vivo Phenomenon in Mice? Anal Chem 2021; 93:10762-10771. [PMID: 34328714 DOI: 10.1021/acs.analchem.0c04316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carbon is the material of choice for electroanalysis of biological systems, being particularly applicable to neurotransmitter analysis as carbon fiber microelectrodes (CFMs). CFMs are most often applied to dopamine detection; however, the scope of CFM analysis has rapidly expanded over the last decade with our laboratory's focus being on improving serotonin detection at CFMs, which we achieved in the past via Nafion modification. We began this present work by seeking to optimize this modification to gain increased analytical sensitivity toward serotonin under the assumption that exposure of bare carbon to the in vivo environment rapidly deteriorates analytical performance. However, we were unable to experimentally verify this assumption and found that electrodes that had been exposed to the in vivo environment were more sensitive to evoked and ambient dopamine. We hypothesized that high in vivo concentrations of ambient extracellular glutamate could polymerize with a negative charge onto CFMs and facilitate response to dopamine. We verified this polymerization electrochemically and characterized the mechanisms of deposition with micro- and nano-imaging. Importantly, we identified that the application of 1.3 V as a positive upper waveform limit is a crucial factor for facilitating glutamate polymerization, thus improving analytical performance. Critically, information gained from these dopamine studies were extended to an in vivo environment where a 2-fold increase in sensitivity to evoked serotonin was achieved. Thus, we present here the novel finding that innate aspects of the in vivo environment are auspicious for detection of dopamine and serotonin at carbon fibers, offering a solution to our goal of an improved fast-scan cyclic voltammetry serotonin detection paradigm.
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Affiliation(s)
- Jordan Holmes
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, 29208 United States
| | - Colby E Witt
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, 29208 United States
| | - Deanna Keen
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, 29208 United States
| | - Anna Marie Buchanan
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, 29208 United States.,Department of Pharmacology, Physiology, & Neuroscience, University of South Carolina SOM, Columbia, South Carolina, 29209 United States
| | - Lauren Batey
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, 29208 United States.,Department of Bioengineering, Imperial College, London, SW7 2AZ UK
| | - Melinda Hersey
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, 29208 United States.,Department of Pharmacology, Physiology, & Neuroscience, University of South Carolina SOM, Columbia, South Carolina, 29209 United States
| | - Parastoo Hashemi
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, 29208 United States.,Department of Bioengineering, Imperial College, London, SW7 2AZ UK
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Giangrasso DM, Furlong TM, Keefe KA. Characterization of striatum-mediated behavior and neurochemistry in the DJ-1 knock-out rat model of Parkinson's disease. Neurobiol Dis 2020; 134:104673. [DOI: 10.1016/j.nbd.2019.104673] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/16/2019] [Accepted: 11/11/2019] [Indexed: 12/27/2022] Open
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Loss of Homeostasis in the Direct Pathway in a Mouse Model of Asymptomatic Parkinson's Disease. J Neurosci 2017; 36:5686-98. [PMID: 27225760 DOI: 10.1523/jneurosci.0492-15.2016] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 03/20/2016] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED The characteristic slowness of movement in Parkinson's disease relates to an imbalance in the activity of striatal medium spiny neurons (MSNs) of the direct (dMSNs) and indirect (iMSNs) pathways. However, it is still unclear whether this imbalance emerges during the asymptomatic phase of the disease or if it correlates with symptom severity. Here, we have used in vivo juxtacellular recordings and transgenic mice showing MSN-type-specific expression of fluorescent proteins to examine striatal imbalance after lesioning dopaminergic neurons of the substantia nigra. Multivariate clustering analysis of behavioral data discriminated 2 groups of dopamine-lesioned mice: asymptomatic (42 ± 7% dopaminergic neuron loss) and symptomatic (85 ± 5% cell loss). Contrary to the view that both pathways have similar gain in control conditions, dMSNs respond more intensely than iMSNs to cortical inputs in control animals. Importantly, asymptomatic mice show significant functional disconnection of dMSNs from motor cortex without changes in iMSN connectivity. Moreover, not only the gain but also the timing of the pathways is altered in symptomatic parkinsonism, where iMSNs fire significantly more and earlier than dMSNs. Therefore, cortical drive to dMSNs decreases after partial nigrostriatal lesions producing no behavioral impairment, but additional alterations in the gain and timing of iMSNs characterize symptomatic rodent parkinsonism. SIGNIFICANCE STATEMENT Prevailing models of Parkinson's disease state that motor symptoms arise from an imbalance in the activity of medium spiny neurons (MSNs) from the direct (dMSNs) and indirect (iMSNs) pathways. Therefore, it is hypothesized that symptom severity and the magnitude of this imbalanced activity are correlated. Using a mouse model of Parkinson's disease, we found that behaviorally undetectable nigrostriatal lesions induced a significant disconnection of dMSNs from the motor cortex. In contrast, iMSNs show an increased connectivity with the motor cortex, but only after a severe dopaminergic lesion associated with an evident parkinsonian syndrome. Overall, our data suggest that the lack of symptoms after a partial dopaminergic lesion is not due to compensatory mechanisms maintaining the activity of both striatal pathways balanced.
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MPTP Mouse Model of Preclinical and Clinical Parkinson’s Disease as an Instrument for Translational Medicine. Mol Neurobiol 2017; 55:2991-3006. [DOI: 10.1007/s12035-017-0559-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 04/12/2017] [Indexed: 02/04/2023]
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8
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Ribeiro JA, Fernandes PM, Pereira CM, Silva F. Electrochemical sensors and biosensors for determination of catecholamine neurotransmitters: A review. Talanta 2016; 160:653-679. [DOI: 10.1016/j.talanta.2016.06.066] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/28/2016] [Accepted: 06/30/2016] [Indexed: 01/03/2023]
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9
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Salvatore MF, Calipari ES, Jones SR. Regulation of Tyrosine Hydroxylase Expression and Phosphorylation in Dopamine Transporter-Deficient Mice. ACS Chem Neurosci 2016; 7:941-51. [PMID: 27124386 DOI: 10.1021/acschemneuro.6b00064] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Tyrosine hydroxylase (TH) and dopamine transporters (DATs) regulate dopamine (DA) neurotransmission at the biosynthesis and reuptake steps, respectively. Dysfunction or loss of these proteins occurs in impaired locomotor or addictive behavior, but little is known about the influence of DAT expression on TH function. Differences in TH phosphorylation, DA tissue content, l-DOPA biosynthesis, and DA turnover exist between the somatodendritic and terminal field compartments of nigrostriatal and mesoaccumbens pathways. We examined whether differential DAT expression affects these compartmental differences in DA regulation by comparing TH expression and phosphorylation at ser31 and ser40. In heterozygous DAT knockout (KO) (+/-) mice, DA tissue content and DA turnover were unchanged relative to wild-type mice, despite a 40% reduction in DAT protein expression. In DAT KO (-/-) mice, DA turnover increased in all DA compartments, but DA tissue content decreased (90-96%) only in terminal fields. TH protein expression and phosphorylation were differentially affected within DA pathway compartments by relative expression of DAT. TH protein decreased (∼74%), though to a significantly lesser extent than DA, in striatum and nucleus accumbens (NAc) in DAT -/- mice, with no decrease in substantia nigra or ventral tegmental area. Striatal ser31 TH phosphorylation and recovery of DA relative to TH protein expression in DAT +/- and DAT -/- mice decreased, whereas ser40 TH phosphorylation increased ∼2- to 3-fold in striatum and NAc of DAT -/- mice. These results suggest that DAT expression affects TH expression and phosphorylation largely in DA terminal field compartments, further corroborating evidence for dichotomous regulation of TH between somatodendritic and terminal field compartments of the nigrostriatal and mesoaccumbens pathways.
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Affiliation(s)
- Michael F. Salvatore
- Department
of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130, United States
| | - Erin S. Calipari
- Department
of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, United States
| | - Sara R. Jones
- Department
of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, United States
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10
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Navntoft CA, Dreyer JK. How compensation breaks down in Parkinson's disease: Insights from modeling of denervated striatum. Mov Disord 2016; 31:280-9. [PMID: 26890687 PMCID: PMC4787207 DOI: 10.1002/mds.26579] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 01/13/2016] [Accepted: 01/22/2016] [Indexed: 12/23/2022] Open
Abstract
The bradykinesia and other motor signs of Parkinson's disease (PD) are linked to progressive loss of substantia nigra dopamine (DA) neurons innervating the striatum. However, the emergence of idiopathic PD is likely preceded by a prolonged subclinical phase, which may be masked by a variety of pre‐ and postsynaptic compensatory mechanisms. It is often considered self‐evident that the signs of PD manifest only when nigrostriatal degeneration has proceeded to such an extent that putative compensatory mechanisms fail to accommodate the depletion of striatal DA levels. However, the precise nature of the compensatory mechanisms, and the reason for their ultimate failure, has been elusive. In a recent computational study we modeled the effects of progressive denervation, including changes in the dynamics of interstitial DA and also adaptive or compensatory changes in postsynaptic responsiveness to DA signaling in the course of progressive nigrostriatal degeneration. In particular, we found that failure of DA signaling can occur by different mechanisms at different disease stages. We review these results and discuss their relevance for clinical and translational research, and we draw a number of predictions from our model that might be tested in preclinical experiments. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
| | - Jakob Kisbye Dreyer
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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11
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Jennings KA, Platt NJ, Cragg SJ. The impact of a parkinsonian lesion on dynamic striatal dopamine transmission depends on nicotinic receptor activation. Neurobiol Dis 2015; 82:262-268. [PMID: 26117304 PMCID: PMC4768081 DOI: 10.1016/j.nbd.2015.06.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/03/2015] [Accepted: 06/20/2015] [Indexed: 01/28/2023] Open
Abstract
Dopamine function is disturbed in Parkinson's disease (PD), but whether and how release of dopamine from surviving neurons is altered has long been debated. Nicotinic acetylcholine receptors (nAChRs) on dopamine axons powerfully govern dopamine release and could be critical contributing factors. We revisited whether fundamental properties of dopamine transmission are changed in a parkinsonian brain and tested the potentially profound masking effects of nAChRs. Using real-time detection of dopamine in mouse striatum after a partial 6-hydroxydopamine lesion and under nAChR inhibition, we reveal that dopamine signals show diminished sensitivity to presynaptic activity. This effect manifested as diminished contrast between DA release evoked by the lowest versus highest frequencies. This reduced activity-dependence was underpinned by loss of short-term facilitation of dopamine release, consistent with an increase in release probability (Pr). With nAChRs active, the reduced activity-dependence of dopamine release after a parkinsonian lesion was masked. Consequently, moment-by-moment variation in activity of nAChRs may lead to dynamic co-variation in dopamine signal impairments in PD. After a parkinsonian lesion, activity-dependence of DA release is impaired. Enhanced Pr and reduced uptake combine to compromise activity-dependence. Dopamine Pr only weakly relates to short-term plasticity of release. nAChR activation abolishes the difference in activity-dependence of DA release between lesion and non-lesion.
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Affiliation(s)
- Katie A Jennings
- Department of Physiology, Anatomy Genetics, Oxford Parkinson's Disease Centre, Parks Road, Oxford OX1 3PT, UK.
| | - Nicola J Platt
- Department of Physiology, Anatomy Genetics, Oxford Parkinson's Disease Centre, Parks Road, Oxford OX1 3PT, UK
| | - Stephanie J Cragg
- Department of Physiology, Anatomy Genetics, Oxford Parkinson's Disease Centre, Parks Road, Oxford OX1 3PT, UK
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12
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Bucher ES, Wightman RM. Electrochemical Analysis of Neurotransmitters. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2015; 8:239-61. [PMID: 25939038 PMCID: PMC4728736 DOI: 10.1146/annurev-anchem-071114-040426] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Chemical signaling through the release of neurotransmitters into the extracellular space is the primary means of communication between neurons. More than four decades ago, Ralph Adams and his colleagues realized the utility of electrochemical methods for the study of easily oxidizable neurotransmitters, such as dopamine, norepinephrine, and serotonin and their metabolites. Today, electrochemical techniques are frequently coupled to microelectrodes to enable spatially resolved recordings of rapid neurotransmitter dynamics in a variety of biological preparations spanning from single cells to the intact brain of behaving animals. In this review, we provide a basic overview of the principles underlying constant-potential amperometry and fast-scan cyclic voltammetry, the most commonly employed electrochemical techniques, and the general application of these methods to the study of neurotransmission. We thereafter discuss several recent developments in sensor design and experimental methodology that are challenging the current limitations defining the application of electrochemical methods to neurotransmitter measurements.
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Robinson JD, Howard CD, Pastuzyn ED, Byers DL, Keefe KA, Garris PA. Methamphetamine-induced neurotoxicity disrupts pharmacologically evoked dopamine transients in the dorsomedial and dorsolateral striatum. Neurotox Res 2014; 26:152-67. [PMID: 24562969 PMCID: PMC4071119 DOI: 10.1007/s12640-014-9459-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 01/10/2014] [Accepted: 02/04/2014] [Indexed: 11/30/2022]
Abstract
Phasic dopamine (DA) signaling, during which burst firing by DA neurons generates short-lived elevations in extracellular DA in terminal fields called DA transients, is implicated in reinforcement learning. Disrupted phasic DA signaling is proposed to link DA depletions and cognitive-behavioral impairment in methamphetamine (METH)-induced neurotoxicity. Here, we further investigated this disruption by assessing effects of METH pretreatment on DA transients elicited by a drug cocktail of raclopride, a D2 DA receptor antagonist, and nomifensine, an inhibitor of the dopamine transporter (DAT). One advantage of this approach is that pharmacological activation provides a large, high-quality data set of transients elicited by endogenous burst firing of DA neurons for analysis of regional differences and neurotoxicity. These pharmacologically evoked DA transients were measured in the dorsomedial (DM) and dorsolateral (DL) striatum of urethane-anesthetized rats by fast-scan cyclic voltammetry. Electrically evoked DA levels were also recorded to quantify DA release and uptake, and DAT binding was determined by means of autoradiography to index DA denervation. Pharmacologically evoked DA transients in intact animals exhibited a greater amplitude and frequency and shorter duration in the DM compared to the DL striatum, despite similar pre- and post-drug assessments of DA release and uptake in both sub-regions as determined from the electrically evoked DA signals. METH pretreatment reduced transient activity. The most prominent effect of METH pretreatment on transients across striatal sub-region was decreased amplitude, which mirrored decreased DAT binding and was accompanied by decreased DA release. Overall, these results identify marked intrastriatal differences in the activity of DA transients that appear independent of presynaptic mechanisms for DA release and uptake and further support disrupted phasic DA signaling mediated by decreased DA release in rats with METH-induced neurotoxicity.
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Affiliation(s)
- John D. Robinson
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | | | - Elissa D. Pastuzyn
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA
| | - Diane L. Byers
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Kristen A. Keefe
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA
| | - Paul A. Garris
- School of Biological Sciences, Illinois State University, Normal, IL, USA
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Howard CD, Daberkow DP, Ramsson ES, Keefe KA, Garris PA. Methamphetamine-induced neurotoxicity disrupts naturally occurring phasic dopamine signaling. Eur J Neurosci 2013; 38:2078-88. [PMID: 23574406 DOI: 10.1111/ejn.12209] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 02/19/2013] [Accepted: 03/02/2013] [Indexed: 01/27/2023]
Abstract
Methamphetamine (METH) is a highly addictive drug that is also neurotoxic to central dopamine (DA) systems. Although striatal DA depletions induced by METH are associated with behavioral and cognitive impairments, the link between these phenomena remains poorly understood. Previous work in both METH-pretreated animals and the 6-hydroxydopamine model of Parkinson's disease suggests that a disruption of phasic DA signaling, which is important for learning and goal-directed behavior, may be such a link. However, previous studies used electrical stimulation to elicit phasic-like DA responses and were also performed under anesthesia, which alters DA neuron activity and presynaptic function. Here we investigated the consequences of METH-induced DA terminal loss on both electrically evoked phasic-like DA signals and so-called 'spontaneous' phasic DA transients measured by voltammetry in awake rats. Not ostensibly attributable to discrete stimuli, these subsecond DA changes may play a role in enhancing reward-cue associations. METH pretreatment reduced tissue DA content in the dorsomedial striatum and nucleus accumbens by ~55%. Analysis of phasic-like DA responses elicited by reinforcing stimulation revealed that METH pretreatment decreased their amplitude and underlying mechanisms for release and uptake to a similar degree as DA content in both striatal subregions. Most importantly, characteristics of DA transients were altered by METH-induced DA terminal loss, with amplitude and frequency decreased and duration increased. These results demonstrate for the first time that denervation of DA neurons alters naturally occurring DA transients and are consistent with diminished phasic DA signaling as a plausible mechanism linking METH-induced striatal DA depletions and cognitive deficits.
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Affiliation(s)
- Christopher D Howard
- Cell Biology, Physiology & Development Section, School of Biological Sciences, Illinois State University, 210 Julian Hall, Normal, IL, 61790-4120, USA
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15
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Chotibut T, Apple DM, Jefferis R, Salvatore MF. Dopamine transporter loss in 6-OHDA Parkinson's model is unmet by parallel reduction in dopamine uptake. PLoS One 2012; 7:e52322. [PMID: 23300642 PMCID: PMC3530604 DOI: 10.1371/journal.pone.0052322] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 11/16/2012] [Indexed: 01/11/2023] Open
Abstract
The dopamine transporter (DAT) regulates synaptic dopamine (DA) in striatum and modulation of DAT can affect locomotor activity. Thus, in Parkinson's disease (PD), DAT loss could affect DA clearance and locomotor activity. The locomotor benefits of L-DOPA may be mediated by transport through monoamine transporters and conversion to DA. However, its impact upon DA reuptake is unknown and may modulate synaptic DA. Using the unilateral 6-OHDA rat PD model, we examined [(3)H]DA uptake dynamics in relation to striatal DAT and tyrosine hydroxylase (TH) protein loss compared with contralateral intact striatum. Despite >70% striatal DAT loss, DA uptake decreased only ∼25% and increased as DAT loss approached 99%. As other monoamine transporters can transport DA, we determined if norepinephrine (NE) and serotonin (5-HT) differentially modulated DA uptake in lesioned striatum. Unlabeled DA, NE, and 5-HT were used, at a concentration that differentially inhibited DA uptake in intact striatum, to compete against [(3)H]DA uptake. In 6-OHDA lesioned striatum, DA was less effective, whereas NE was more effective, at inhibiting [(3)H]DA uptake. Furthermore, norepinephrine transporter (NET) protein levels increased and desipramine was ∼two-fold more effective at inhibiting NE uptake. Serotonin inhibited [(3)H]DA uptake, but without significant difference between lesioned and contralateral striatum. L-DOPA inhibited [(3)H]DA uptake two-fold more in lesioned striatum and inhibited NE uptake ∼five-fold more than DA uptake in naïve striatum. Consequently, DA uptake may be mediated by NET when DAT loss is at PD levels. Increased inhibition of DA uptake by L-DOPA and its preferential inhibition of NE over DA uptake, indicates that NET-mediated DA uptake may be modulated by L-DOPA when DAT loss exceeds 70%. These results indicate a novel mechanism for DA uptake during PD progression and provide new insight into how L-DOPA affects DA uptake, revealing possible mechanisms of its therapeutic and side effect potential.
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Affiliation(s)
- Tanya Chotibut
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America
| | - Deana M. Apple
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America
| | - Rebecca Jefferis
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America
| | - Michael F. Salvatore
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America
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Miller EM, Pomerleau F, Huettl P, Russell VA, Gerhardt GA, Glaser PEA. The spontaneously hypertensive and Wistar Kyoto rat models of ADHD exhibit sub-regional differences in dopamine release and uptake in the striatum and nucleus accumbens. Neuropharmacology 2012; 63:1327-34. [PMID: 22960443 DOI: 10.1016/j.neuropharm.2012.08.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 07/31/2012] [Accepted: 08/21/2012] [Indexed: 10/27/2022]
Abstract
The most widely used animal model of attention-deficit/hyperactivity disorder (ADHD) is the spontaneously hypertensive rat (SHR/NCrl), which best represents the combined subtype (ADHD-C). Recent evidence has revealed that a progenitor strain, the Wistar Kyoto from Charles River Laboratories (WKY/NCrl), is useful as a model of the inattentive subtype (ADHD-PI) and the Wistar Kyoto from Harlan Laboratories (WKY/NHsd) and the Sprague Dawley (SD) have been suggested as controls. Dopamine (DA) dysfunction in the striatum (Str) and nucleus accumbens core (NAc) is thought to play a significant role in the pathophysiology of ADHD but data obtained with the SHR is equivocal. Using high-speed chronoamperometric recordings with carbon fiber microelectrodes, we found that the SHR/NCrl displayed decreased KCl-evoked DA release versus the WKY/NCrl model of ADHD-PI in the dorsal Str. The WKY/NCrl and the WKY/NHsd control did not differ from each other; however, the control SD released less DA than the WKY/NCrl model of ADHD-PI in the dorsal Str and less than the control WKY/NHsd in the intermediate Str. The SHR/NCrl had faster DA uptake in the ventral Str and NAc versus both control strains, while the WKY/NCrl model of ADHD-PI exhibited faster DA uptake in the NAc versus the SD control. These results suggest that increased surface expression of DA transporters may explain the more rapid uptake of DA in the Str and NAc of these rodent models of ADHD.
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Affiliation(s)
- Erin M Miller
- Department of Anatomy & Neurobiology, University of Kentucky College of Medicine, 138 Leader Avenue, Lexington, KY 40506, USA
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Bergstrom BP. Using in vivo voltammetry to demonstrate drug action: a student laboratory experience in neurochemistry. JOURNAL OF UNDERGRADUATE NEUROSCIENCE EDUCATION : JUNE : A PUBLICATION OF FUN, FACULTY FOR UNDERGRADUATE NEUROSCIENCE 2012; 10:A113-7. [PMID: 23504500 PMCID: PMC3598088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 01/12/2012] [Accepted: 02/06/2012] [Indexed: 06/01/2023]
Abstract
Providing undergraduate neuroscience students an appropriate laboratory experience that demonstrates principles of neurotransmission and drug action is a difficult task. In the following activity, fast-scan cyclic voltammetry was utilized to measure dopamine levels using carbon-fiber microelectrodes in rats in vivo. Recordings were made before and after administration of several drugs to assess their ability to alter extracellular dopamine. The following drugs were chosen due to their well established actions: haloperidol, methylphenidate, and alpha-methyl-para-tyrosine. Each demonstrated markedly altered extracellular dopamine dynamics and some basic kinetic analysis enabled students to attribute the alterations to differing modes of action. Dopamine tissue content was also assessed to compare the differences between acute drug action and overall neurotransmitter content. Any neuroscience laboratory course that desired to demonstrate principles involved in neurotransmission would be well served by the activities involved. This laboratory experience provided: 1) basic principles in experimental design, 2) small animal surgical experiences, 3) exposure to common instrumentation used in collecting neurochemical data, 4) data analysis procedures, and 5) experience in presenting their findings.
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Affiliation(s)
- Brian P. Bergstrom
- Biology Department, Neuroscience Program, Muskingum University, New Concord, OH 43762
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