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Khsime I, Boulain M, Fettah A, Chagraoui A, Courtand G, De Deurwaerdère P, Juvin L, Barrière G. Limiting Monoamines Degradation Increases L-DOPA Pro-Locomotor Action in Newborn Rats. Int J Mol Sci 2023; 24:14747. [PMID: 37834195 PMCID: PMC10572489 DOI: 10.3390/ijms241914747] [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: 07/28/2023] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
L-DOPA, the precursor of catecholamines, exerts a pro-locomotor action in several vertebrate species, including newborn rats. Here, we tested the hypothesis that decreasing the degradation of monoamines can promote the pro-locomotor action of a low, subthreshold dose of L-DOPA in five-day-old rats. The activity of the degrading pathways involving monoamine oxidases or catechol-O-methyltransferase was impaired by injecting nialamide or tolcapone, respectively. At this early post-natal stage, the capacity of the drugs to trigger locomotion was investigated by monitoring the air-stepping activity expressed by the animals suspended in a harness above the ground. We show that nialamide (100 mg/kg) or tolcapone (100 mg/kg), without effect on their own promotes maximal expression of air-stepping sequences in the presence of a sub-effective dose of L-DOPA (25 mg/kg). Tissue measurements of monoamines (dopamine, noradrenaline, serotonin and some of their metabolites) in the cervical and lumbar spinal cord confirmed the regional efficacy of each inhibitor toward their respective enzyme. Our experiments support the idea that the raise of monoamines boost L-DOPA's locomotor action. Considering that both inhibitors differently altered the spinal monoamines levels in response to L-DOPA, our data also suggest that maximal locomotor response can be reached with different monoamines environment.
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Affiliation(s)
- Inès Khsime
- Univ. Bordeaux, CNRS, INCIA, UMR5287, F-33000 Bordeaux, France (A.F.); (G.C.); (L.J.)
| | - Marie Boulain
- Univ. Bordeaux, CNRS, INCIA, UMR5287, F-33000 Bordeaux, France (A.F.); (G.C.); (L.J.)
| | - Abderrahman Fettah
- Univ. Bordeaux, CNRS, INCIA, UMR5287, F-33000 Bordeaux, France (A.F.); (G.C.); (L.J.)
| | - Abdeslam Chagraoui
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, UNIROUEN, INSERM U1239, Institute for Research and Innovation in Biomedicine of Normandy (IRIB), F-76000 Rouen, France;
- Department of Medical Biochemistry, Rouen University Hospital, CHU de Rouen, F-76000 Rouen, France
| | - Gilles Courtand
- Univ. Bordeaux, CNRS, INCIA, UMR5287, F-33000 Bordeaux, France (A.F.); (G.C.); (L.J.)
| | | | - Laurent Juvin
- Univ. Bordeaux, CNRS, INCIA, UMR5287, F-33000 Bordeaux, France (A.F.); (G.C.); (L.J.)
| | - Grégory Barrière
- Univ. Bordeaux, CNRS, INCIA, UMR5287, F-33000 Bordeaux, France (A.F.); (G.C.); (L.J.)
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2
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Olaya MDP, Vergel NE, López JL, Viña D, Guerrero MF. 8-Propyl-6H-[1,3]dioxolo[4,5-g]chromen-6-one: A new coumarin with monoamine oxidase B inhibitory activity and possible anti-parkinsonian effects. BRAZ J PHARM SCI 2020. [DOI: 10.1590/s2175-97902019000317609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Coumarin analogue 3-methyl-7H-furo[3,2-g] chromen-7-one as a possible antiparkinsonian agent. ACTA ACUST UNITED AC 2019; 39:491-501. [PMID: 31584763 PMCID: PMC7357371 DOI: 10.7705/biomedica.4299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Indexed: 11/30/2022]
Abstract
Introduction: Parkinson’s disease is the second most common neurodegenerative disease. Monoamine oxidase B inhibitors are used in the treatment of this disease concomitantly with levodopa or as monotherapy. Several substituted coumarins have shown activity as inhibitors of monoamine oxidase B. Objective: To evaluate the possible antiparkinsonian effects of the coumarin analogue FCS005 (3-methyl-7H-furo[3,2-g]chromen-7-one) in mouse models, as well as its inhibitory activity towards monoamine oxidases (MAO) and its antioxidant activity. Materials and methods: FCS005 was synthesized and the reversal of hypokinesia was evaluated in the reserpine and levodopa models. Moreover, in the haloperidol model, its anticataleptic effects were evaluated. Additionally, the monoamine oxidase inhibitory activity and antioxidant activity of FCS005 were evaluated using in vitro and ex vivo studies, respectively. Results: FCS005 (100 mg/kg) caused the reversal of hypokinesia in the reserpine and levodopa models. This furocoumarin also presented anti-cataleptic effects at the same dose. Besides, it showed selective inhibitory activity towards the MAO-B isoform and antioxidant activity. Conclusion: These results attribute interesting properties to the compound FCS005. It is important to continue research on this molecule considering that it could be a potential antiparkinsonian agent.
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Ugryumov MV. Dopamine Synthesis by Non-Dopaminergic Neurons as an Effective Mechanism of Neuroplasticity. NEUROCHEM J+ 2018. [DOI: 10.1134/s1819712418040086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Passiflora cincinnata Extract Delays the Development of Motor Signs and Prevents Dopaminergic Loss in a Mice Model of Parkinson's Disease. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 2017:8429290. [PMID: 28835767 PMCID: PMC5556616 DOI: 10.1155/2017/8429290] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/20/2017] [Indexed: 02/02/2023]
Abstract
Passiflora cincinnata Masters is a Brazilian native species of passionflower. This genus is known in the American continent folk medicine for its diuretic and analgesic properties. Nevertheless, few studies investigated possible biological effects of P. cincinnata extracts. Further, evidence of antioxidant actions encourages the investigation of possible neuroprotective effects in animal models of neurodegenerative diseases. This study investigates the effect of the P. cincinnata ethanolic extract (PAS) on mice submitted to a progressive model of Parkinson's disease (PD) induced by reserpine. Male (6-month-old) mice received reserpine (0.1 mg/kg, s.c.), every other day, for 40 days, with or without a concomitant treatment with daily injections of PAS (25 mg/kg, i.p.). Catalepsy, open field, oral movements, and plus-maze discriminative avoidance evaluations were performed across treatment, and immunohistochemistry for tyrosine hydroxylase was conducted at the end. The results showed that PAS treatment delayed the onset of motor impairments and prevented the occurrence of increased catalepsy behavior in the premotor phase. However, PAS administration did not modify reserpine-induced cognitive impairments. Moreover, PAS prevented the decrease in tyrosine hydroxylase immunostaining in the substantia nigra pars compacta (SNpc) induced by reserpine. Taken together, our results suggested that PAS exerted a neuroprotective effect in a progressive model of PD.
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Di Giovanni G, Svob Strac D, Sole M, Unzeta M, Tipton KF, Mück-Šeler D, Bolea I, Della Corte L, Nikolac Perkovic M, Pivac N, Smolders IJ, Stasiak A, Fogel WA, De Deurwaerdère P. Monoaminergic and Histaminergic Strategies and Treatments in Brain Diseases. Front Neurosci 2016; 10:541. [PMID: 27932945 PMCID: PMC5121249 DOI: 10.3389/fnins.2016.00541] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 11/07/2016] [Indexed: 12/18/2022] Open
Abstract
The monoaminergic systems are the target of several drugs for the treatment of mood, motor and cognitive disorders as well as neurological conditions. In most cases, advances have occurred through serendipity, except for Parkinson's disease where the pathophysiology led almost immediately to the introduction of dopamine restoring agents. Extensive neuropharmacological studies first showed that the primary target of antipsychotics, antidepressants, and anxiolytic drugs were specific components of the monoaminergic systems. Later, some dramatic side effects associated with older medicines were shown to disappear with new chemical compounds targeting the origin of the therapeutic benefit more specifically. The increased knowledge regarding the function and interaction of the monoaminergic systems in the brain resulting from in vivo neurochemical and neurophysiological studies indicated new monoaminergic targets that could achieve the efficacy of the older medicines with fewer side-effects. Yet, this accumulated knowledge regarding monoamines did not produce valuable strategies for diseases where no monoaminergic drug has been shown to be effective. Here, we emphasize the new therapeutic and monoaminergic-based strategies for the treatment of psychiatric diseases. We will consider three main groups of diseases, based on the evidence of monoamines involvement (schizophrenia, depression, obesity), the identification of monoamines in the diseases processes (Parkinson's disease, addiction) and the prospect of the involvement of monoaminergic mechanisms (epilepsy, Alzheimer's disease, stroke). In most cases, the clinically available monoaminergic drugs induce widespread modifications of amine tone or excitability through neurobiological networks and exemplify the overlap between therapeutic approaches to psychiatric and neurological conditions. More recent developments that have resulted in improved drug specificity and responses will be discussed in this review.
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Affiliation(s)
| | | | - Montse Sole
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Institut de Neurociències, Universitat Autònoma de BarcelonaBarcelona, Spain
| | - Mercedes Unzeta
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Institut de Neurociències, Universitat Autònoma de BarcelonaBarcelona, Spain
| | - Keith F. Tipton
- School of Biochemistry and Immunology, Trinity College DublinDublin, Ireland
| | - Dorotea Mück-Šeler
- Division of Molecular Medicine, Rudjer Boskovic InstituteZagreb, Croatia
| | - Irene Bolea
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Institut de Neurociències, Universitat Autònoma de BarcelonaBarcelona, Spain
| | | | | | - Nela Pivac
- Division of Molecular Medicine, Rudjer Boskovic InstituteZagreb, Croatia
| | - Ilse J. Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit BrusselBrussels, Belgium
| | - Anna Stasiak
- Department of Hormone Biochemistry, Medical University of LodzLodz, Poland
| | - Wieslawa A. Fogel
- Department of Hormone Biochemistry, Medical University of LodzLodz, Poland
| | - Philippe De Deurwaerdère
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5293), Institut of Neurodegenerative DiseasesBordeaux Cedex, France
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De Deurwaerdère P, Di Giovanni G, Millan MJ. Expanding the repertoire of L-DOPA's actions: A comprehensive review of its functional neurochemistry. Prog Neurobiol 2016; 151:57-100. [PMID: 27389773 DOI: 10.1016/j.pneurobio.2016.07.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/18/2016] [Accepted: 07/03/2016] [Indexed: 01/11/2023]
Abstract
Though a multi-facetted disorder, Parkinson's disease is prototypically characterized by neurodegeneration of nigrostriatal dopaminergic neurons of the substantia nigra pars compacta, leading to a severe disruption of motor function. Accordingly, L-DOPA, the metabolic precursor of dopamine (DA), is well-established as a treatment for the motor deficits of Parkinson's disease despite long-term complications such as dyskinesia and psychiatric side-effects. Paradoxically, however, despite the traditional assumption that L-DOPA is transformed in residual striatal dopaminergic neurons into DA, the mechanism of action of L-DOPA is neither simple nor entirely clear. Herein, focussing on its influence upon extracellular DA and other neuromodulators in intact animals and experimental models of Parkinson's disease, we highlight effects other than striatal generation of DA in the functional profile of L-DOPA. While not excluding a minor role for glial cells, L-DOPA is principally transformed into DA in neurons yet, interestingly, with a more important role for serotonergic than dopaminergic projections. Moreover, in addition to the striatum, L-DOPA evokes marked increases in extracellular DA in frontal cortex, nucleus accumbens, the subthalamic nucleus and additional extra-striatal regions. In considering its functional profile, it is also important to bear in mind the marked (probably indirect) influence of L-DOPA upon cholinergic, GABAergic and glutamatergic neurons in the basal ganglia and/or cortex, while anomalous serotonergic transmission is incriminated in the emergence of L-DOPA elicited dyskinesia and psychosis. Finally, L-DOPA may exert intrinsic receptor-mediated actions independently of DA neurotransmission and can be processed into bioactive metabolites. In conclusion, L-DOPA exerts a surprisingly complex pattern of neurochemical effects of much greater scope that mere striatal transformation into DA in spared dopaminergic neurons. Their further experimental and clinical clarification should help improve both L-DOPA-based and novel strategies for controlling the motor and other symptoms of Parkinson's disease.
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Affiliation(s)
- Philippe De Deurwaerdère
- CNRS (Centre National de la Recherche Scientifique), Institut des Maladies Neurodégénératives, UMR CNRS 5293, F-33000 Bordeaux, France.
| | - Giuseppe Di Giovanni
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, UK; Department of Physiology & Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta
| | - Mark J Millan
- Institut de Recherche Servier, Pole for Therapeutic Innovation in Neuropsychiatry, 78290 Croissy/Seine,Paris, France
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8
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Lizarraga LE, Cholanians AB, Phan AV, Herndon JM, Lau SS, Monks TJ. Vesicular monoamine transporter 2 and the acute and long-term response to 3,4-(±)-methylenedioxymethamphetamine. Toxicol Sci 2014; 143:209-19. [PMID: 25370842 DOI: 10.1093/toxsci/kfu222] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
3,4-(±)-Methylenedioxymethamphetamine (MDMA, Ecstasy) is a ring-substituted amphetamine derivative with potent psychostimulant properties. The neuropharmacological effects of MDMA are biphasic in nature, initially causing synaptic monoamine release, primarily of serotonin (5-HT). Conversely, the long-term effects of MDMA manifest as prolonged depletions in 5-HT, and reductions in 5-HT reuptake transporter (SERT), indicative of serotonergic neurotoxicity. MDMA-induced 5-HT efflux relies upon disruption of vesicular monoamine storage, which increases cytosolic 5-HT concentrations available for release via a carrier-mediated mechanism. The vesicular monoamine transporter 2 (VMAT2) is responsible for packaging monoamine neurotransmitters into cytosolic vesicles. Thus, VMAT2 is a molecular target for a number of psychostimulant drugs, including methamphetamine and MDMA. We investigated the effects of depressed VMAT2 activity on the adverse responses to MDMA, via reversible inhibition of the VMAT2 protein with Ro4-1284. A single dose of MDMA (20 mg/kg, subcutaneous) induced significant hyperthermia in rats. Ro4-1284 (10 mg/kg, intraperitoneal) pretreatment prevented the thermogenic effects of MDMA, instead causing a transient decrease in body temperature. MDMA-treated rats exhibited marked increases in horizontal velocity and rearing behavior. In the presence of Ro4-1284, MDMA-mediated horizontal hyperlocomotion was delayed and attenuated, whereas rearing activity was abolished. Finally, Ro4-1284 prevented deficits in 5-HT content in rat cortex and striatum, and reduced depletions in striatal SERT staining, 7 days after MDMA administration. In summary, acute inhibition of VMAT2 by Ro4-1284 protected against MDMA-mediated hyperthermia, hyperactivity, and serotonergic neurotoxicity. The data suggest the involvement of VMAT2 in the thermoregulatory, behavioral, and neurotoxic effects of MDMA.
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Affiliation(s)
- Lucina E Lizarraga
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721
| | - Aram B Cholanians
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721
| | - Andy V Phan
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721
| | - Joseph M Herndon
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721
| | - Serrine S Lau
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721
| | - Terrence J Monks
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721
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9
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Myczek K, Yeung ST, Castello N, Baglietto-Vargas D, LaFerla FM. Hippocampal adaptive response following extensive neuronal loss in an inducible transgenic mouse model. PLoS One 2014; 9:e106009. [PMID: 25184527 PMCID: PMC4153578 DOI: 10.1371/journal.pone.0106009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 07/25/2014] [Indexed: 11/19/2022] Open
Abstract
Neuronal loss is a common component of a variety of neurodegenerative disorders (including Alzheimer's, Parkinson's, and Huntington's disease) and brain traumas (stroke, epilepsy, and traumatic brain injury). One brain region that commonly exhibits neuronal loss in several neurodegenerative disorders is the hippocampus, an area of the brain critical for the formation and retrieval of memories. Long-lasting and sometimes unrecoverable deficits caused by neuronal loss present a unique challenge for clinicians and for researchers who attempt to model these traumas in animals. Can these deficits be recovered, and if so, is the brain capable of regeneration following neuronal loss? To address this significant question, we utilized the innovative CaM/Tet-DT(A) mouse model that selectively induces neuronal ablation. We found that we are able to inflict a consistent and significant lesion to the hippocampus, resulting in hippocampally-dependent behavioral deficits and a long-lasting upregulation in neurogenesis, suggesting that this process might be a critical part of hippocampal recovery. In addition, we provide novel evidence of angiogenic and vasculature changes following hippocampal neuronal loss in CaM/Tet-DTA mice. We posit that angiogenesis may be an important factor that promotes neurogenic upregulation following hippocampal neuronal loss, and both factors, angiogenesis and neurogenesis, can contribute to the adaptive response of the brain for behavioral recovery.
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Affiliation(s)
- Kristoffer Myczek
- Department of Neurobiology and Behavior and Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California, United States of America
| | - Stephen T. Yeung
- Department of Neurobiology and Behavior and Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California, United States of America
| | - Nicholas Castello
- Department of Neurobiology and Behavior and Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California, United States of America
| | - David Baglietto-Vargas
- Department of Neurobiology and Behavior and Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California, United States of America
| | - Frank M. LaFerla
- Department of Neurobiology and Behavior and Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California, United States of America
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Ugrumov MV. Brain neurons partly expressing dopaminergic phenotype: location, development, functional significance, and regulation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 68:37-91. [PMID: 24054140 DOI: 10.1016/b978-0-12-411512-5.00004-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In addition to catecholaminergic neurons possessing all the enzymes of catecholamine synthesis and the specific membrane transporters, neurons partly expressing the catecholaminergic phenotype have been found a quarter of a century ago. Most of them express individual enzymes of dopamine (DA) synthesis, tyrosine hydroxylase (TH), or aromatic l-amino acid decarboxylase (AADC), lacking the DA membrane transporter and the vesicular monoamine transporter, type 2. These so-called monoenzymatic neurons are widely distributed throughout the brain in ontogenesis and adulthood being in some brain regions even more numerous than dopaminergic (DA-ergic) neurons. Individual enzymes of DA synthesis are expressed in these neurons continuously or transiently in norm and pathology. It has been proven that monoenzymatic TH neurons and AADC neurons are capable of producing DA in cooperation. It means that l-3,4-dihydroxyphenylalanine (l-DOPA) synthesized from l-tyrosine in monoenzymatic TH neurons is transported to monoenzymatic AADC neurons for DA synthesis. Such cooperative synthesis of DA is considered as a compensatory reaction under a failure of DA-ergic neurons, for example, in neurodegenerative diseases like hyperprolactinemia and Parkinson's disease. Moreover, l-DOPA, produced in monoenzymatic TH neurons, is assumed to play a role of a neurotransmitter or neuromodulator affecting the target neurons via catecholamine receptors. Thus, numerous widespread neurons expressing individual complementary enzymes of DA synthesis serve to produce DA in cooperation that is a compensatory reaction at failure of DA-ergic neurons.
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Affiliation(s)
- Michael V Ugrumov
- Institute of Developmental Biology and Centre for Brain Research, Russian Academy of Sciences, Moscow, Russia; Institute of Normal Physiology RAMS, Moscow, Russia.
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11
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Locomotor response to L-DOPA in reserpine-treated rats following central inhibition of aromatic L-amino acid decarboxylase: further evidence for non-dopaminergic actions of L-DOPA and its metabolites. Neurosci Res 2010; 68:44-50. [PMID: 20542064 DOI: 10.1016/j.neures.2010.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 06/02/2010] [Accepted: 06/03/2010] [Indexed: 11/22/2022]
Abstract
L-DOPA is the most widely used treatment for Parkinson's disease. The anti-parkinsonian and pro-dyskinetic actions of L-DOPA are widely attributed to its conversion, by the enzyme aromatic L-amino acid decarboxylase (AADC), to dopamine. We investigated the hypothesis that exogenous L-DOPA can induce behavioural effects without being converted to dopamine in the reserpine-treated rat-model of Parkinson's disease. A parkinsonian state was induced with reserpine (3 mg/kg s.c.). Eighteen hours later, the rats were administered L-DOPA plus the peripherally acting AADC inhibitor benserazide (25 mg/kg), with or without the centrally acting AADC inhibitor NSD1015 (100 mg/kg). L-DOPA/benserazide alone reversed reserpine-induced akinesia (4158+/-1125 activity counts/6 h, cf vehicle 1327+/-227). Addition of NSD1015 elicited hyperactive behaviour that was approximately 7-fold higher than L-DOPA/benserazide (35755+/-5226, P<0.001). The hyperactivity induced by L-DOPA and NSD1015 was reduced by the alpha(2C) antagonist rauwolscine (1 mg/kg) and the 5-HT(2C) agonist MK212 (5 mg/kg), but not by the D2 dopamine receptor antagonist remoxipride (3 mg/kg) or the D1 dopamine receptor antagonist SCH23390 (1 mg/kg). These data suggest that L-DOPA, or metabolites produced via routes not involving AADC, might be responsible for the generation of at least some L-DOPA actions in reserpine-treated rats.
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Viaro R, Marti M, Morari M. Dual motor response to l-dopa and nociceptin/orphanin FQ receptor antagonists in 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) treated mice: Paradoxical inhibition is relieved by D(2)/D(3) receptor blockade. Exp Neurol 2010; 223:473-84. [PMID: 20122926 DOI: 10.1016/j.expneurol.2010.01.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/19/2010] [Accepted: 01/23/2010] [Indexed: 11/29/2022]
Abstract
Motor activity of mice acutely treated with the parkinsonian toxin 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) was monitored for 6 days using behavioral tests which provide complementary information on motor function: the bar, reaction time, drag, stair climbing, grip, rotarod and footprinting tests. These tests consistently disclosed a prolonged motor impairment characterized by akinesia, bradykinesia, speed reduction, loss of coordination and gait patterns. This impairment was associated with approximately 60% loss of striatal dopamine terminals, as revealed by tyrosine hydroxylase immunohistochemistry, and was attenuated by dopaminergic drugs. Indeed, the dopamine precursor, l-dopa (1-10 mg/kg), and the D(3)/D(2) receptor agonist pramipexole (0.0001-0.001 mg/kg) promoted stepping activity in the drag test (a test for akinesia/bradykinesia). The novel nociceptin/orphanin FQ receptor (NOP) antagonist 1-[1-(cyclooctylmethyl)-1,2,3,6-tetrahydro-5-(hydroxymethyl)-4-pyridinyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one (Trap-101, 0.001-0.1 mg/kg), an analogue of 1-[(3R,4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one (J-113397), also promoted stepping and synergistically or additively (depending on test) attenuated parkinsonism when combined to dopamine agonists. High doses of l-dopa (100 mg/kg), pramipexole (0.1 mg/kg), Trap-101 and J-113397 (1 mg/kg), however, failed to modulate stepping, worsening immobility time and/or rotarod performance. Low doses of amisulpride (0.1 mg/kg) reversed motor inhibition induced by l-dopa and J-113397, suggesting involvement of D(2)/D(3) receptors. This study brings further evidence for a dopamine-dependent motor phenotype in MPTP-treated mice reinforcing the view that this model can be predictive of symptomatic antiparkinsonian activity provided the appropriate test is used. Moreover, it offers mechanistic interpretation to clinical reports of paradoxical worsening of parkinsonism following l-dopa. Finally, it confirms that NOP receptor antagonists may be proven effective in reversing parkinsonism when administered alone or in combination with dopamine agonists.
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Affiliation(s)
- Riccardo Viaro
- Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara, Ferrara, Italy
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Distinct effects of intranigral L-DOPA infusion in the MPTP rat model of Parkinson's disease. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2010. [PMID: 20411784 DOI: 10.1007/978-3-211-92660-4_21] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
The potential neuroprotective or neurotoxic effects of 3,4-dihydroxyphenylalanine (L-DOPA) are yet to be understood. We examined the behavioral, immunohistochemical, tyrosine hydroxylase (TH) expression and neurochemical parameters after an intranigral administration of L-DOPA (10 microM) in rats. L-DOPA elicited a 30.5% reduction in dopaminergic neurons, while 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (100 microg microL(-1)) produced a 53.6% reduction. A combined infusion of MPTP and L-DOPA generated a 42% reduction of nigral neurons. Motor parameters revealed that both the MPTP and L-DOPA groups presented impairments; however, the concomitant administration evoked a partial restorative effect. In addition, MPTP and L-DOPA separately induced reductions of TH protein expression within the substantia nigra. In contrast, the coadministration of MPTP and L-DOPA did not demonstrate such difference. The striatal levels of dopamine were reduced after MPTP or L-DOPA, with an increased turnover only for the MPTP group. In view of such results, it seems reasonable to suggest that L-DOPA could potentially produce dopaminergic neurotoxicity.
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Alachkar A, Brotchie JM, Jones OT. Binding of dopamine and 3-methoxytyramine as l-DOPA metabolites to human alpha(2)-adrenergic and dopaminergic receptors. Neurosci Res 2010; 67:245-9. [PMID: 20302892 DOI: 10.1016/j.neures.2010.03.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 03/11/2010] [Accepted: 03/12/2010] [Indexed: 11/28/2022]
Abstract
The ability of l-3,4-dihydroxyphenylalanine (l-DOPA), l-DOPA-methyl ester and their major metabolites, dopamine, dihydroxyphenylacetic acid (DOPAC), homovanillic (HVA), 3-O-methyldopa and 3-methoxytyramine (3-MT) to bind to alpha(2) adrenergic and D1 and D2 dopamine receptors was assessed by radioligand binding to cloned human receptors expressed in cell lines. As anticipated, dopamine bound with high affinity to D1 (IC(50) 1.1 + or - 0.16 microM) and D2 (IC(50) 0.7 + or - 0.3 microM) dopamine receptors. However, dopamine also bound with high affinity to alpha(2A) (IC(50) was 2.6 + or - 0.5 microM), alpha(2C) (IC(50) 3.2 + or - 0.7 microM). 3-MT bound to alpha(2A) with high affinity (IC(50), 3.6 + or - 0.2 microM) though moderate affinity to alpha(2)c, D1 and D2 receptors (values of IC(50) were 55 + or - 14, 121 + or - 43, 36 + or - 14 microM, respectively). l-DOPA-methyl ester bound with high affinity to alpha(2) (IC(50) 17-36 microM) but not dopamine receptors (IC(50) 0.9-2.5 mM). l-DOPA, 3-O-methyldopa and DOPAC had no observable effect on binding to any of the receptors tested. These data suggest that the effects of l-DOPA in Parkinson's disease may result from actions of its metabolites dopamine and 3-MT on both dopaminergic and non-dopaminergic receptors. These findings may provide explanations for the differences between l-DOPA and dopamine receptor agonists in mediating anti-parkinsonian effects and propensity to be associated with dyskinesia and motor complications such as wearing-off and on-off.
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Affiliation(s)
- Amal Alachkar
- Division of Neuroscience, School of Biological Sciences, University of Manchester, Manchester M13 9PT, UK.
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Navailles S, Bioulac B, Gross C, De Deurwaerdère P. Serotonergic neurons mediate ectopic release of dopamine induced by L-DOPA in a rat model of Parkinson's disease. Neurobiol Dis 2010; 38:136-43. [PMID: 20096781 DOI: 10.1016/j.nbd.2010.01.012] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Accepted: 01/14/2010] [Indexed: 11/28/2022] Open
Abstract
Benefit and motor side effects of l-DOPA in Parkinson's disease have been related to dopamine transmission in the striatum. However, the putative involvement of serotonergic neurons in the dopaminergic effects of l-DOPA suggests that the striatum is not a preferential target of l-DOPA. By using microdialysis in a rat model of Parkinson's disease, we found that l-DOPA (3-100 mg/kg) increased dopamine extracellular levels monitored simultaneously in four brain regions receiving serotonergic innervation: striatum, substantia nigra, hippocampus, prefrontal cortex. The increase was regionally similar at the lowest dose and 2-3 times stronger in the striatum at higher doses. Citalopram, a serotonin reuptake blocker, or the destruction of serotonergic fibers by 5,7-dihydroxytryptamine impaired l-DOPA-induced dopamine release in all regions. These data demonstrate that l-DOPA induces an ectopic release of dopamine due to serotonergic neurons. The new pattern of dopamine transmission created by l-DOPA may contribute to the benefit and side effects of l-DOPA.
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Affiliation(s)
- Sylvia Navailles
- Université de Bordeaux, Unité Mixte de Recherche Centre National de la Recherche Scientifique 5227, Centre Hospitalier Universitaire de Bordeaux, 33076 Bordeaux cedex, France
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Behavioral disinhibition and reduced anxiety-like behaviors in monoamine oxidase B-deficient mice. Neuropsychopharmacology 2009; 34:2746-57. [PMID: 19710633 PMCID: PMC2783894 DOI: 10.1038/npp.2009.118] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Monoamine oxidase (MAO) B catalyzes the degradation of beta-phenylethylamine (PEA), a trace amine neurotransmitter implicated in mood regulation. Although several studies have shown an association between low MAO B activity in platelets and behavioral disinhibition in humans, the nature of this relation remains undefined. To investigate the impact of MAO B deficiency on the emotional responses elicited by environmental cues, we tested MAO B knockout (KO) mice in a set of behavioral assays capturing different aspects of anxiety-related manifestations, such as the elevated plus maze, defensive withdrawal, marble burying, and hole board. Furthermore, MAO B KO mice were evaluated for their exploratory patterns in response to unfamiliar objects and risk-taking behaviors. In comparison with their wild-type (WT) littermates, MAO B KO mice exhibited significantly lower anxiety-like responses and shorter latency to engage in risk-taking behaviors and exploration of unfamiliar objects. To determine the neurobiological bases of the behavioral differences between WT and MAO B KO mice, we measured the brain-regional levels of PEA in both genotypes. Although PEA levels were significantly higher in all brain regions of MAO B KO in comparison with WT mice, the most remarkable increments were observed in the striatum and prefrontal cortex, two key regions for the regulation of behavioral disinhibition. However, no significant differences in transcript levels of PEA's selective receptor, trace amine-associated receptor 1 (TAAR1), were detected in either region. Taken together, these results suggest that MAO B deficiency may lead to behavioral disinhibition and decreased anxiety-like responses partially through regional increases of PEA levels.
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Non-dopaminergic neurons partly expressing dopaminergic phenotype: distribution in the brain, development and functional significance. J Chem Neuroanat 2009; 38:241-56. [PMID: 19698780 DOI: 10.1016/j.jchemneu.2009.08.004] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2009] [Revised: 08/06/2009] [Accepted: 08/12/2009] [Indexed: 11/23/2022]
Abstract
Besides the dopaminergic (DA-ergic) neurons possessing the whole set of enzymes of DA synthesis from l-tyrosine and the DA membrane transporter (DAT), the neurons partly expressing the DA-ergic phenotype have been first discovered two decades ago. Most of the neurons express individual enzymes of DA synthesis, tyrosine hydroxylase (TH) or aromatic l-amino acid decarboxylase (AADC) and lack the DAT. A list of the neurons partly expressing the DA-ergic phenotype is not restricted to so-called monoenzymatic neurons, e.g. it includes some neurons co-expressing both enzymes of DA synthesis but lacking the DAT. In contrast to true DA-ergic neurons, monoenzymatic neurons and bienzymatic non-dopaminergic neurons lack the vesicular monoamine transporter 2 (VMAT2) that raises a question about the mechanisms of storing and release of their final synthetic products. Monoenzymatic neurons are widely distributed all through the brain in adulthood being in some brain regions even more numerous than DA-ergic neurons. Individual enzymes of DA synthesis are expressed in these neurons continuously or transiently in norm or under certain physiological conditions. Monoenzymatic neurons, particularly those expressing TH, appear to be even more numerous and more widely distributed in the brain during ontogenesis than in adulthood. Most populations of monoenzymatic TH neurons decrease in number or even disappear by puberty. Functional significance of monoenzymatic neurons remained uncertain for a long time after their discovery. Nevertheless, it has been shown that most monoenzymatic TH neurons and AADC neurons are capable to produce l-3,4-dihydroxyphenylalanine (L-DOPA) from l-tyrosine and DA from L-DOPA, respectively. L-DOPA produced in monoenzymatic TH neurons is assumed to play a role of a neurotransmitter or neuromodulator acting on target neurons via catecholamine receptors. Moreover, according to our hypothesis L-DOPA released from monoenzymatic TH neurons is captured by monoenzymatic AADC neurons for DA synthesis. Such cooperative synthesis of DA is considered as a compensatory reaction under a failure of DA-ergic neurons, e.g. in neurodegenerative diseases like hyperprolactinemia and Parkinson's disease.Thus, a substantial number of the brain neurons express partly the DA-ergic phenotype, mostly individual complementary enzymes of DA synthesis, serving to produce DA in cooperation that is supposed to be a compensatory reaction under the failure of DA-ergic neurons.
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Findrik Z, Vasić-Rački Ð, Primožič M, Habulin M, Knez Ž. Enzymatic activity ofL-amino acid oxidase from snake venomCrotalus adamanteusin supercritical CO2. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420500285694] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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In vivo antagonism of the behavioral responses to L-3-,4-dihydroxyphenylalanine by L-3-,4-dihydroxyphenylalanine cyclohexyl ester in conscious rats. Eur J Pharmacol 2009; 605:109-13. [DOI: 10.1016/j.ejphar.2008.12.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 12/14/2008] [Accepted: 12/23/2008] [Indexed: 11/18/2022]
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Hadjiconstantinou M, Neff NH. Enhancing aromatic L-amino acid decarboxylase activity: implications for L-DOPA treatment in Parkinson's disease. CNS Neurosci Ther 2009; 14:340-51. [PMID: 19040557 DOI: 10.1111/j.1755-5949.2008.00058.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Aromatic L-amino acid decarboxylase (AAAD) is an essential enzyme for the formation of catecholamines, indolamines, and trace amines. Moreover, it is a required enzyme for converting L-DOPA to dopamine when treating patients with Parkinson's disease (PD). There is now substantial evidence that the activity of AAAD in striatum is regulated by activation and induction, and second messengers play a role. Enzyme activity can be modulated by drugs acting on a number of neurotransmitter receptors including dopamine (D1-4), glutamate (NMDA), serotonin (5-HT(1A), 5-HT(2A)) and nicotinic acetylcholine receptors. Generally, antagonists enhance AAAD activity; while, agonists may diminish it. Enhancement of AAAD activity is functional, as the formation of dopamine from exogenous L-DOPA mirrors activity. Following a lesion of nigrostriatal dopaminergic neurons, AAAD in striatum responds more robustly to pharmacological manipulations, and this is true for the decarboxylation of exogenous L-DOPA as well. We review the evidence for parallel modulation of AAAD activity and L-DOPA decarboxylation and propose that this knowledge can be exploited to optimize the formation of dopamine from exogenous L-DOPA. This information can be used as a blue print for the design of novel L-DOPA treatment adjuvants to benefit patients with PD.
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Affiliation(s)
- Maria Hadjiconstantinou
- Division of Molecular Neuropsychopharmacology, Department of Psychiatry, College of Medicine, Ohio State University, Columbus, OH 43210, USA
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Owen JCE, Whitton PS. Effects of amantadine and budipine on antidepressant drug-evoked changes in extracellular dopamine in the frontal cortex of freely moving rats. Brain Res 2006; 1117:206-12. [PMID: 16996043 DOI: 10.1016/j.brainres.2006.07.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Revised: 07/05/2006] [Accepted: 07/13/2006] [Indexed: 11/26/2022]
Abstract
NMDA receptors play a role in the aetiology of depression with non-competitive NMDA receptor antagonists such as amantadine showing synergy with conventional antidepressants. To advance a neurochemical rational for these findings, we have studied the effects of administration of amantadine and budipine with the antidepressants reboxetine (REB), paroxetine (PAROX) and clomipramine (CLOM) on extracellular DA in rats using microdialysis. Acutely, amantadine (40 mg/kg) or budipine (10 mg/kg) did not significantly alter extracellular DA. REB (10 mg/kg), PAROX (10 mg/kg) both increased cortical DA while CLOM (10 mg/kg) produced a decrease. When amantadine or budipine was administered 30 min before the antidepressants, DA increases were markedly greater than following the antidepressants alone. Chronically drug effects were studied at 4, 7, 14 and 21 days. Amantadine and budipine did not significantly alter extracellular DA at any time. The three antidepressants elicited a gradual increase in DA which became significant after 7 days and tended to plateau thereafter. When amantadine (20 mg/kg) or budipine (5 mg/kg) was co-administered with the three antidepressants, two differences were seen compared with the antidepressants alone. Firstly, the time required for significant increases in cortical DA was reduced with elevated levels now being observed by 4 days. Secondly, the increase in extracellular DA was greater in these rats throughout the experiment. If increased extracellular DA represents a step in the mechanism of action of antidepressants, these data suggest that combined treatment with clinically tolerated NMDA antagonists such as amantadine could reduce the delay in therapeutic onset of antidepressants and possibly enhance their efficacy.
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Affiliation(s)
- Jenny C E Owen
- The School of Pharmacy, Department of Pharmacology, 29-39 Brunswick Square, London WC1N 1AX, Great Britain UK
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Silva I, Cortes H, Escartín E, Rangel C, Florán L, Erlij D, Aceves J, Florán B. L-DOPA inhibits depolarization-induced [3H]GABA release in the dopamine-denervated globus pallidus of the rat: the effect is dopamine independent and mediated by D2-like receptors. J Neural Transm (Vienna) 2006; 113:1847-53. [PMID: 16736236 DOI: 10.1007/s00702-006-0493-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Accepted: 02/07/2006] [Indexed: 10/24/2022]
Abstract
The effect of L-DOPA on [(3)H]GABA release in slices of globus pallidus from 6-OHDA-lesioned rats was studied. Release was evoked by high (15 mM) K(+). The lesion reduced dopamine content and dopamine synthesized from L-DOPA. The inhibition of DOPA decarboxylase blocked dopamine synthesis. Endogenous dopamine released by high K(+) inhibited [(3)H]GABA release in normal but not in lesioned slices. L-DOPA inhibited (IC(50) = 0.44 microM) evoked [(3)H]GABA release. The inhibition was via D2-like receptors but not mediated by dopamine. The turning behavior induced by L-DOPA methyl ester (25 mg/kg, i.p.) was not abolished by the DOPA decarboxylase inhibitor 3-hydroxybenzylhydrazine but in this condition it was abolished by sulpiride. Results suggest that L-DOPA acting as D2-like agonist inhibits GABA release in the rat globus pallidus and induces turning behavior in rats with unilateral lesions of the dopamine innervation. L-DOPA could control Parkinson's disease symptoms acting not only as dopamine precursor but also by itself.
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Affiliation(s)
- I Silva
- Departamento de Fisiología, Biofísica y Neurociencias del CINVESTAV, México, México
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Modelling of l-DOPA enzymatic oxidation catalyzed by l-amino acid oxidases from Crotalus adamanteus and Rhodococcus opacus. Biochem Eng J 2006. [DOI: 10.1016/j.bej.2005.08.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bamford NS, Robinson S, Palmiter RD, Joyce JA, Moore C, Meshul CK. Dopamine modulates release from corticostriatal terminals. J Neurosci 2005; 24:9541-52. [PMID: 15509741 PMCID: PMC6730145 DOI: 10.1523/jneurosci.2891-04.2004] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Normal striatal function is dependent on the availability of synaptic dopamine to modulate neurotransmission. Within the striatum, excitatory inputs from cortical glutamatergic neurons and modulatory inputs from midbrain dopamine neurons converge onto dendritic spines of medium spiny neurons. In addition to dopamine receptors on medium spiny neurons, D2 receptors are also present on corticostriatal terminals, where they act to dampen striatal excitation. To determine the effect of dopamine depletion on corticostriatal activity, we used the styryl dye FM1-43 in combination with multiphoton confocal microscopy in slice preparations from dopamine-deficient (DD) and reserpine-treated mice. The activity-dependent release of FM1-43 out of corticostriatal terminals allows a measure of kinetics quantified by the halftime decay of fluorescence intensity. In DD, reserpine-treated, and control mice, exposure to the D2-like receptor agonist quinpirole revealed modulation of corticostriatal kinetics with depression of FM1-43 destaining. In DD and reserpine-treated mice, quinpirole decreased destaining to a greater extent, and at a lower dose, consistent with hypersensitive corticostriatal D2 receptors. Compared with controls, slices from DD mice did not react to amphetamine or to cocaine with dopamine-releasing striatal stimulation unless the animals were pretreated with l-3,4-dihydroxyphenylalanine (l-dopa). Electron microscopy and immunogold labeling for glutamate terminals within the striatum demonstrated that the observed differences in kinetics of corticostriatal terminals in DD mice were not attributable to aberrant cytoarchitecture or glutamate density. Microdialysis revealed that basal extracellular striatal glutamate was normal in DD mice. These data indicate that dopamine deficiency results in morphologically normal corticostriatal terminals with hypersensitive D2 receptors.
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Walter B, Brust P, Füchtner F, Müller M, Hinz R, Kuwabara H, Fritz H, Zwiener U, Bauer R. Age-Dependent Effects of Severe Traumatic Brain Injury on Cerebral Dopaminergic Activity in Newborn and Juvenile Pigs. J Neurotrauma 2004; 21:1076-89. [PMID: 15319007 DOI: 10.1089/0897715041651024] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There is evidence that the dopaminergic system is sensitive to traumatic brain injury (TBI). However, the age-dependency of this sensitivity has not been studied together with brain oxidative metabolism. We postulate that the acute effects of severe TBI on brain dopamine turnover are age-dependent. Therefore 18F-labelled 6-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) together with Positron-Emission-Tomography (PET) was used to estimate the activity of the aromatic amino acid decarboxylase (AADC) in the brain of 11 newborn piglets (7-10 days old) and nine juvenile pigs (6-7 weeks old). Six newborn and five juvenile animals were subjected to a severe fluid-percussion (FP) induced TBI. The remaining animals were used as sham operated untreated control groups. Simultaneously, the regional cerebral blood flow (CBF) was measured with colored microspheres and the cerebral metabolic rates of oxygen and glucose were determined. At 1 h after FP-TBI, [18F]FDOPA was infused and PET scanning was performed for 2 h. At 2 h after FP-TBI administration, a second series of measurements of physiological values including CBF and brain oxidative metabolism data had been obtained. Severe FP-TBI elicited a marked increase in the rate constant for fluorodopamine production (k3FDOPA) in all brain regions of newborn piglets studied by between 97% (mesencephalon) and 143% (frontal cortex) (p < 0.05). In contrast, brain hemodynamics and cerebral oxidative metabolism remained unaltered after TBI. Furthermore, the permeability-surface area product of FDOPA (PSFDOPA) was unchanged. In addition, regional blood flow differences between corresponding ipsi- and contralateral brain regions did not occur after TBI. Thus, it is suggested that severe FP-TBI induces an upregulation of AADC activity of newborn piglets that is not related to alterations in brain oxidative metabolism.
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Affiliation(s)
- Bernd Walter
- Department of Neurosurgery, Friedrich Schiller University Jena, Germany
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Peeters M, Romieu P, Maurice T, Su TP, Maloteaux JM, Hermans E. Involvement of the sigma 1 receptor in the modulation of dopaminergic transmission by amantadine. Eur J Neurosci 2004; 19:2212-20. [PMID: 15090047 DOI: 10.1111/j.0953-816x.2004.03297.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pharmacological effects of amantadine on dopaminergic transmission are proposed to result from an uncompetitive antagonism at glutamate N-methyl-D-aspartate (NMDA) receptors. However, our previous studies examining amantadine-mediated dopamine receptor regulation in the rat striatum revealed a discrepancy from a direct interference with glutamate transmission. Preliminary in vitro binding data from the literature suggested the interaction of amantadine with the sigma1 receptor. Therefore, we have now further characterized the pharmacological properties of amantadine and memantine at this receptor and investigated its involvement in the modulation of striatal dopaminergic transmission. Our binding studies using [3H]-(+)SKF-10,047 indicated that amantadine and memantine behave as ligands of the sigma(1) receptor in rat forebrain homogenates (Ki values of 7.44 +/- 0.82 and 2.60 +/- 0.62 microm, respectively). In NG108-15 neuroblastoma cells, both drugs (amantadine (100 microm) and memantine (10 microm)) potentiated the bradykinin-induced mobilization of intracellular Ca2+, mimicking the effect of the sigma1 receptor agonist PRE-084 (1 microm). Finally, we previously showed that in striatal membranes from amantadine-treated rats, the functional coupling of dopamine receptors with G-proteins was enhanced. Similarly, PRE-084 dose-dependently increased the [35S]GTPgammaS binding induced by dopamine (Emax 28 and 26% of basal, 0.3 and 1 mg/kg PRE-084, respectively). By contrast, BD1047, which is without effect on its own, antagonized the effects of amantadine and PRE-084. Together, these data demonstrate that aminoadamantanes behave as sigma1 receptor agonists, and confirm an involvement of this receptor in modulating dopamine receptors exerted by therapeutically relevant concentrations of amantadine.
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Affiliation(s)
- Magali Peeters
- Laboratoire de Pharmacologie Expérimentale (FARL), Université catholique de Louvain, 54.10, Avenue Hippocrate 54, B-1200 Brussels, Belgium
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Gołembiowska K, Dziubina A. Effect of the adenosine A2A receptor antagonist 8-(3-chlorostyryl)caffeine on l-DOPA biotransformation in rat striatum. Brain Res 2004; 998:208-17. [PMID: 14751592 DOI: 10.1016/j.brainres.2003.11.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the present study, we investigated effects of the new selective adenosine A2A receptor antagonist 8-(3-chlorostyryl)caffeine (CSC) on L-DOPA-induced dopamine (DA) release in the striatum of intact and reserpine-treated rats. CSC given in a pharmacologically effective dose of 5 mg/kg i.p. significantly increased striatal DA release after joint administration of L-DOPA (100 mg/kg, i.p.) and benserazide (50 mg/kg, i.p.) to intact and reserpine (2.5 mg/kg, s.c.)-injected rats. CSC did not change the elevated level of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in intact rats, but raised it in DA-depleted animals. The availability of exogenous L-DOPA in the extracellular space was similar and equally increased by CSC in both intact and reserpinized rats. Our results suggest that the observed effects may be mediated by striatal adenosine A2A receptors, and are probably related to the CSC action on DA metabolism and the increased transport of exogenous L-DOPA into the brain. These observations might be of relevance, considering the use of selective A2A antagonists as potential supplements to L-DOPA therapy of Parkinson's disease.
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Affiliation(s)
- Krystyna Gołembiowska
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Kraków, Poland.
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He JC, Yuan CX, Wei HC, Chen RX. Effect of Chinese and western medicine integration on spinning behavior of rats with Parkinson disease. ACTA ACUST UNITED AC 2003; 1:293-5. [PMID: 15339536 DOI: 10.3736/jcim20030419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To observe the effect of Chinese and western medicine integration on the spinning behavior of rats with Parkinson disease. METHODS Model of the lateral Parkinson disease was made with injection of 6-hydroxydopamine (6-OHDA) into the black substance of the right side of the brain, and the model rats were treated with madopar and Chinese herbs for nourishing the liver and kidney, clearing collaterals and detoxification. The rat's spinning behavior was observed, and was compared with the normal control group, madopar group and sham-operation group at the same time. RESULTS Chinese and western medicine integration could obviously reduce the spinning circles of the rats. CONCLUSION Chinese and western medicine integration can significantly improve the spinning behavior of the model rats.
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Affiliation(s)
- Jian-Cheng He
- Department of Traditional Chinese Medicine Diagnosis, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China.
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Abstract
Alterations in the cytosolic pool directly affect neurotransmitter synthesis and release and are suggested to be key factors in various neurodegenerative disorders. Although this cytosolic pool is the most metabolically active, it is miniscule compared with the amount of vesicular transmitter and has never been quantified separately. Here, we introduce intracellular patch electrochemistry (IPE), a technique that for the first time provides direct measurements of cytosolic oxidizable molecules in single mammalian cells. In amperometric mode, IPE detects total catechols, whereas in cyclic voltammetric mode, it preferentially measures catecholamines. In cultured chromaffin cells, the total cytosolic catechol concentration was 50-500 microm, of which approximately 10% were catecholamines. Reserpine, a vesicular monoamine transporter inhibitor, had no effect on the catecholamine pool but increased total catechols by fourfold to fivefold. Combined with pargyline, a monoamine oxidase inhibitor, reserpine increased catecholamine levels in the cytosol by approximately sixfold. Amphetamine induced a transient approximately fivefold accumulation of cytosolic catecholamines and a slow increase of total catechols. In cells incubated with 3,4-dihydroxy-L-phenylalanine (L-DOPA), catecholamines increased by approximately 2.5-fold and total catechols increased by approximately fourfold. Cytosolic catecholamines returned to control levels <or=10 min after L-DOPA withdrawal, whereas total catechols remained approximately twofold elevated even after a 1.5 hr incubation in L-DOPA-free media. Our data indicate that cytosolic catecholamines are strictly maintained at a defined level, and drug-induced increases in their concentrations lead to the accumulation of other catecholamine derivatives, such as DOPAC and 3,4-dihydroxyphenylethyleneglycol. These derivatives reside in the cytosol for hours after treatment and may be an underlying cause of drug-related cytotoxicity.
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Lopez-Real A, Rodriguez-Pallares J, Guerra MJ, Labandeira-Garcia JL. Localization and functional significance of striatal neurons immunoreactive to aromatic L-amino acid decarboxylase or tyrosine hydroxylase in rat Parkinsonian models. Brain Res 2003; 969:135-46. [PMID: 12676374 DOI: 10.1016/s0006-8993(03)02291-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Striatal neurons which are immunoreactive (ir) to aromatic L-amino-acid decarboxylase (AADC) or tyrosine hydrodroxylase (TH) may play a role in the decarboxylation of L-DOPA to dopamine (DA) in advanced stages of Parkinson's disease (PD). However, the functional significance of these neurons and the mechanisms responsible for their induction remain to be clarified. In this study, rats were subjected to different types of dopaminergic or serotonergic denervation and L-DOPA injection to study the effects on these neurons. AADC-ir neurons were found in both normal and DA-denervated striata, and no significant differences in their number and distribution were induced following different types of denervation or L-DOPA administration. TH-ir neurons were only found in DA-denervated striata. However, TH-ir neurons did not appear in those areas with maximal DA depletion, but rather were observed near spared or partially lesioned DA terminals. The population of AADC-ir neurons may make a significant contribution to the effects of exogenous L-DOPA in advanced stages of PD. In addition, TH-ir neurons may contribute to these effects, since we have detected AADC-ir in TH-ir neurons using confocal laser scanning microscopy. Finally, neither L-DOPA therapy nor serotonergic denervation induces significant changes in the number or distribution of these neurons.
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Affiliation(s)
- Ana Lopez-Real
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain
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Gross CE, Ravenscroft P, Dovero S, Jaber M, Bioulac B, Bezard E. Pattern of levodopa-induced striatal changes is different in normal and MPTP-lesioned mice. J Neurochem 2003; 84:1246-55. [PMID: 12614325 DOI: 10.1046/j.1471-4159.2003.01600.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
While levodopa-induced neurochemical changes have been studied in animal models of Parkinson's disease, very little is known regarding the effects of levodopa administration in normal animals. The present study investigates the effects normal and MPTP-lesioned mice chronically treated with two different doses of levodopa. We assess changes in striatal dopamine (DA) receptor binding, striatal DA receptor mRNA levels and striatal neuropeptide precursor levels (preproenkephalin-A [PPE-A]; preprotachykinin [PPT]; preproenkephalin-B [PPE-B]). The extent of the lesion was measured by striatal DA transporter binding and stereological estimation of the number of tyrosine hydroxylase immunoreactive neurones in the substantia nigra pars compacta (SNc). In non-lesioned animals, chronic levodopa treatment induced an increase in PPE-A mRNA, whereas both D3R binding and PPE-B mRNA levels were dramatically increased in the lesioned animals in a dose dependent manner. The present results show that chronic levodopa administration may induce pathophysiological changes, even in the absence of a lesion of the nigro-striatal pathway, suggesting that the sensitization process involves predominantly the indirect striatofugal pathway in non-lesioned animals, whereas the direct pathway is primarily involved in lesioned animals.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
- Animals
- Antiparkinson Agents/pharmacology
- Binding, Competitive/drug effects
- Chronic Disease
- Corpus Striatum/drug effects
- Corpus Striatum/metabolism
- Corpus Striatum/pathology
- Disease Models, Animal
- Dopamine Plasma Membrane Transport Proteins
- Enkephalins/genetics
- Enkephalins/metabolism
- Levodopa/pharmacology
- Male
- Membrane Glycoproteins
- Membrane Transport Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Nerve Tissue Proteins
- Neural Pathways/drug effects
- Neural Pathways/pathology
- Neurons/metabolism
- Neurons/pathology
- Parkinsonian Disorders/chemically induced
- Parkinsonian Disorders/drug therapy
- Parkinsonian Disorders/pathology
- Protein Precursors/genetics
- Protein Precursors/metabolism
- RNA, Messenger/metabolism
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, Dopamine D3
- Substantia Nigra/metabolism
- Substantia Nigra/pathology
- Tachykinins/genetics
- Tachykinins/metabolism
- Tyrosine 3-Monooxygenase/biosynthesis
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Affiliation(s)
- Christian E Gross
- Basal Gang, Laboratoire de Neurophysiologie, Universitè Victor Segalen, Bordeaux Cedex, France
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32
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Misu Y, Kitahama K, Goshima Y. L-3,4-Dihydroxyphenylalanine as a neurotransmitter candidate in the central nervous system. Pharmacol Ther 2003; 97:117-37. [PMID: 12559386 DOI: 10.1016/s0163-7258(02)00325-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Historically, 3,4-dihydroxyphenylalanine (DOPA) has been believed to be an inert amino acid that alleviates the symptoms of Parkinson's disease by its conversion to dopamine via the enzyme aromatic L-amino acid decarboxylase. In contrast to this generally accepted idea, we propose that DOPA itself is a neurotransmitter and/or neuromodulator, in addition to being a precursor of dopamine. Several criteria, such as synthesis, metabolism, active transport, existence, physiological release, competitive antagonism, and physiological or pharmacological responses, must be satisfied before a compound is accepted as a neurotransmitter. Recent evidence suggests that DOPA fulfills these criteria in its involvement mainly in baroreflex neurotransmission in the lower brainstem and in delayed neuronal death by transient ischemia in the striatum and the hippocampal CA1 region of rats.
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Affiliation(s)
- Yoshimi Misu
- Department of Pharmacology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
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33
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Tozawa Y, Matsushima K. Peripheral 5-HT(2A)-receptor-mediated formation of an inhibitor of atrial natriuretic peptide binding involves inflammation. Eur J Pharmacol 2002; 440:37-44. [PMID: 11959086 DOI: 10.1016/s0014-2999(02)01310-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A peripheral 5-HT(2A) receptor-mediated hemodynamic change prompted formation of indole-2,3-dione, an endogenous inhibitor of atrial natriuretic peptide (ANP) receptor binding and G protein-mediated intracellular signaling (IC(50): 0.4 microM). This effect was significantly suppressed by dexamethasone, indomethacin and the 5-HT(2) receptor antagonists, ketanserin or ritanserin. 5-HT(2A) receptor-mediated acute hemodynamic change was not modified significantly by indomethacin, prazosin or propranolol pretreatment. A tyrosine hydroxylase inhibitor, alpha-methyl-p-tyrosine, but not a dopamine beta hydroxylase inhibitor, diethyldithiocarbamate, abolished the 5-HT(2A) receptor-mediated increase in indole-2,3-dione. Exogenous indole-2,3-dione induced a significant increase in plasma catecholamine levels and decrease in urine volume. A 5-HT(2A) receptor-mediated decrease in capillary flow may have caused an inflammatory process and peripheral sympathetic activation via ANP signaling inhibition. 3,4-dihydroxyphenylalanine (DOPA)/dopamine may contribute to the progression of inflammation or the generation of a precursor of indole-2,3-dione. The observation that indole-2,3-dione abolished angiotensin AT(1) receptor-mediated NADPH activation in both human umbilical vein endothelial cells and smooth muscle cells at 20 microM may suggest that sulfhydryl-reactive indole-2,3-dione could influence mitochondrial function and cellular redox states via flavoenzyme inhibition and/or regulation of dehydrogenase-oxidase conversion.
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MESH Headings
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Atrial Natriuretic Factor/antagonists & inhibitors
- Atrial Natriuretic Factor/metabolism
- Catecholamines/blood
- Cyclooxygenase Inhibitors/pharmacology
- Dexamethasone/pharmacology
- Ditiocarb/pharmacology
- Dopamine beta-Hydroxylase/antagonists & inhibitors
- Dose-Response Relationship, Drug
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Humans
- Indomethacin/pharmacology
- Inflammation/metabolism
- Isatin/metabolism
- Isatin/pharmacology
- Ketanserin/pharmacology
- Muscle, Smooth/cytology
- Muscle, Smooth/drug effects
- Muscle, Smooth/metabolism
- Prazosin/pharmacology
- Propranolol/pharmacology
- Protein Binding
- Rats
- Rats, Wistar
- Reactive Oxygen Species/metabolism
- Receptor, Angiotensin, Type 1
- Receptor, Serotonin, 5-HT2A
- Receptors, Angiotensin/physiology
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/physiology
- Reserpine/pharmacology
- Ritanserin/pharmacology
- Serotonin/analogs & derivatives
- Serotonin/pharmacology
- Serotonin Receptor Agonists/pharmacology
- Tyrosine 3-Monooxygenase/antagonists & inhibitors
- Urination/drug effects
- Vascular Resistance/drug effects
- Yohimbine/pharmacology
- alpha-Methyltyrosine/pharmacology
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Affiliation(s)
- Yumiko Tozawa
- Department of Molecular Preventive Medicine, School of Medicine, University of Tokyo, Tokyo, Japan.
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Jonkers N, Sarre S, Ebinger G, Michotte Y. MK801 suppresses the L-DOPA-induced increase of glutamate in striatum of hemi-Parkinson rats. Brain Res 2002; 926:149-55. [PMID: 11814417 DOI: 10.1016/s0006-8993(01)03147-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In vivo microdialysis in freely moving rats was used to investigate the influence of the indirect dopamine receptor agonist levodopa (L-DOPA), alone and combined with the N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK801), on extracellular glutamate levels in the striatum of intact and 6-hydroxydopamine-lesioned rats. L-DOPA (25 mg/kg i.p. after benserazide 10 mg/kg i.p.) increased extracellular glutamate levels in the striatum of both intact and dopamine-depleted rats. A prior injection of MK801 (0.1 and 1.0 mg/kg i.p.) did not alter the L-DOPA-induced glutamate release in the striatum of intact rats. In contrast, the L-DOPA-induced increase in glutamate in the striatum of 6-hydroxydopamine-lesioned rats was suppressed by MK801 (0.1 mg/kg i.p.). The data presented here suggest that NMDA receptors do not play a role in the L-DOPA-induced increase in striatal glutamate in intact rats but are involved in the glutamate release in the dopamine-depleted striatum. The suppression of this increase by prior administration of MK801 could represent a neuroprotective effect.
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Affiliation(s)
- Nadine Jonkers
- Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
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35
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Sánchez-Pernaute R, Harvey-White J, Cunningham J, Bankiewicz KS. Functional effect of adeno-associated virus mediated gene transfer of aromatic L-amino acid decarboxylase into the striatum of 6-OHDA-lesioned rats. Mol Ther 2001; 4:324-30. [PMID: 11592835 DOI: 10.1006/mthe.2001.0466] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In animal models of Parkinson's disease, gene transfer of aromatic L-amino acid decarboxylase (AADC) leads to an increase in the capacity of the striatum to decarboxylate exogenous L-DOPA. However, the functional effects of enhanced L-DOPA to dopamine conversion have not been explored. Here, we show that following adeno-associated virus (AAV)-AADC transduction, the transgenic AADC is able to decarboxylate exogenous L-DOPA more efficiently so that a dose of L-DOPA ineffective before gene transfer elicits a motor asymmetry (rotational behavior) following gene transfer. Furthermore, rotation scores showed a strong correlation with AADC activity in the lesioned striatum, thus allowing for behavioral screening of successful gene transfer in the brain. In animals receiving AAV2-AADC, dopamine production was restored to 50% of normal levels 12 weeks after the infusion. Microdialysis experiments demonstrated an in vivo enhanced conversion of L-DOPA to dopamine, but no storage capacity as dopamine was released to the extracellular space in a continuous, nonregulated fashion. In addition to the potential clinical benefit of improving decarboxylation efficiency in Parkinson's disease, our approach may be relevant for the treatment of AADC deficiency, a rare, autosomal recessive disorder causing a severe movement disorder and progressive cognitive impairment.
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Affiliation(s)
- R Sánchez-Pernaute
- Molecular Therapeutics Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland 20892, USA
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36
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Lopez A, Muñoz A, Guerra MJ, Labandeira-Garcia JL. Mechanisms of the effects of exogenous levodopa on the dopamine-denervated striatum. Neuroscience 2001; 103:639-51. [PMID: 11274784 DOI: 10.1016/s0306-4522(00)00588-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The efficacy of exogenous levodopa (L-DOPA) is attributed to its conversion to dopamine by the enzyme aromatic L-amino-acid decarboxylase in striatal dopaminergic terminals. However, there is controversy about the mechanisms underlying the therapeutic and adverse effects of L-DOPA after almost all striatal dopaminergic afferents have disappeared (i.e. in the later stages of Parkinson's disease). After administration of 30mg/kg or 100mg/kg of L-DOPA, rats subjected to unilateral dopaminergic denervation showed intense contraversive rotation and a high density of Fos-immunoreactive nuclei throughout the denervated striatum, with no significant induction of Fos in the intact striatum. Injection of the central aromatic L-amino-acid decarboxylase inhibitor NSD-1015 30min before and 15min after the injection of L-DOPA suppressed the rotational behavior and the striatal induction of Fos. Comparison of results obtained in rats subjected to unilateral and bilateral dopaminergic denervation indicated that the presence of contralateral dopaminergic innervation does not significantly modulate the effects of L-DOPA on the denervated striatum. Serotonergic denervation led to slight and statistically non-significant decrease in the rotational behavior and Fos expression induced by high doses of L-DOPA (100mg/kg) in the dopamine-denervated striatum, but totally suppressed the rotational behavior and Fos expression induced by low doses of L-DOPA (30mg/kg). The present data indicate that the major effects observed after administration of exogenous L-DOPA are not due to a direct action of L-DOPA on dopamine receptors, or to extrastriatal release of dopamine, but to conversion of L-DOPA to dopamine by serotonergic terminals and probably some intrastriatal cells. Given that serotonergic neurons appear to play an important role in the action of L-DOPA in the later stages of Parkinson's disease, strategies targeting the serotonergic system should be considered for the treatment of Parkinson's disease and for combating undesirable side effects of L-DOPA therapy.
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Affiliation(s)
- A Lopez
- Department of Morphological Sciences, University of Santiago de Compostela, Galicia, Spain
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37
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Treseder SA, Rose S, Jenner P. The central aromatic amino acid DOPA decarboxylase inhibitor, NSD-1015, does not inhibit L-DOPA-induced circling in unilateral 6-OHDA-lesioned-rats. Eur J Neurosci 2001; 13:162-70. [PMID: 11135014 DOI: 10.1046/j.0953-816x.2000.01370.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The centrally acting aromatic amino acid dopa decarboxylase (AADC) inhibitor, 3-hydroxybenzyl hydrazine (NSD-1015), is widely used to study the neurotransmitter-like actions of L-DOPA. However, the effects of NSD-1015 on L-DOPA-induced motor activity are unclear as both increases and decreases have been reported. We now investigate the effects of NSD-1015 on L-DOPA-induced contralateral circling behaviour in 6-OHDA-lesioned rats and on striatal levels of L-DOPA, 3-O-methyl-DOPA (3-OMD), dopamine, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) using microdialysis techniques. NSD-1015 (50-200 mg/kg i.p.) inhibited AADC activity both in the liver and striatum of normal rats. Administration of NSD-1015 (50-200 mg/kg i.p.), delayed the onset of circling produced by administration of L-DOPA (25 mg/kg i.p.) and carbidopa (12.5 mg/kg i. p.), suggesting blockade of central AADC activity. However, the duration of the L-DOPA-induced circling was prolonged and overall no inhibition of circling behaviour occurred. L-DOPA (25 mg/kg i.p.) plus carbidopa (12.5 mg/kg i.p.) increased extracellular levels of L-DOPA, 3-OMD, dopamine, DOPAC and HVA in the 6-OHDA-lesioned striatum. Pretreatment of rats with the central AADC inhibitor, NSD-1015 (100 mg/kg i.p.), potentiated the increase in dialysate levels of L-DOPA and 3-OMD. However, it did not reduce striatal dopamine levels in the 6-OHDA-lesioned hemisphere, which were elevated following L-DOPA administration. The increases in DOPAC and HVA levels were abolished by NSD-1015 pretreatment. These results suggest that, while NSD-1015 blocks central AADC activity, it also acts as a monoamine oxidase inhibitor so maintaining striatal dopamine concentration by reducing dopamine metabolism. NSD-1015, therefore, may not be an appropriate tool for the study of brain AADC activity and for assessing the neuromodulatory role of L-DOPA.
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Affiliation(s)
- S A Treseder
- Neurodegenenerative Disease Research Centre, Division of Pharmacology & Therapeutics, Guy's, King's and St Thomas' School of Biomedical Sciences, King's College, London, Guy's Campus, London, SE1 1UL, UK
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38
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Jonkers N, Sarre S, Ebinger G, Michotte Y. MK801 influences L-DOPA-induced dopamine release in intact and hemi-parkinson rats. Eur J Pharmacol 2000; 407:281-91. [PMID: 11068024 DOI: 10.1016/s0014-2999(00)00753-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In vivo microdialysis was used to investigate the influence of dizocilpine (MK801) on basal and levodopa (L-DOPA)-induced extracellular dopamine levels in striatum and substantia nigra of intact and 6-hydroxydopamine-lesioned rats. In lesioned rats, extracellular dopamine was decreased in striatum but not in substantia nigra. L-DOPA (25 mg/kg i.p. after benserazide 10 mg/kg i. p.) increased the dopamine levels in striatum and substantia nigra of intact and dopamine-depleted rats. This increase was significantly higher in dopamine-depleted compared to intact striatum. Pretreatment with MK801 (0.1 and 1.0 mg/kg i.p.) dose-dependently attenuated the L-DOPA-induced dopamine release in substantia nigra of intact rats. In dopamine-depleted striatum, MK801 enhanced L-DOPA-induced dopamine release. The present results indicate that the influence of MK801 on L-DOPA-induced dopamine release in striatum and substantia nigra depends on the integrity of the nigrostriatal pathway. In Parkinson's disease, NMDA receptor antagonists could be beneficial by enhancing the therapeutic efficacy of L-DOPA at the level of the striatum.
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Affiliation(s)
- N Jonkers
- Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
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