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Dekundy A, Pichler G, El Badry R, Scheschonka A, Danysz W. Amantadine for Traumatic Brain Injury-Supporting Evidence and Mode of Action. Biomedicines 2024; 12:1558. [PMID: 39062131 PMCID: PMC11274811 DOI: 10.3390/biomedicines12071558] [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: 06/27/2024] [Accepted: 07/10/2024] [Indexed: 07/28/2024] Open
Abstract
Traumatic brain injury (TBI) is an important global clinical issue, requiring not only prevention but also effective treatment. Following TBI, diverse parallel and intertwined pathological mechanisms affecting biochemical, neurochemical, and inflammatory pathways can have a severe impact on the patient's quality of life. The current review summarizes the evidence for the utility of amantadine in TBI in connection to its mechanism of action. Amantadine, the drug combining multiple mechanisms of action, may offer both neuroprotective and neuroactivating effects in TBI patients. Indeed, the use of amantadine in TBI has been encouraged by several clinical practice guidelines/recommendations. Amantadine is also available as an infusion, which may be of particular benefit in unconscious patients with TBI due to immediate delivery to the central nervous system and the possibility of precise dosing. In other situations, orally administered amantadine may be used. There are several questions that remain to be addressed: can amantadine be effective in disorders of consciousness requiring long-term treatment and in combination with drugs approved for the treatment of TBI? Do the observed beneficial effects of amantadine extend to disorders of consciousness due to factors other than TBI? Well-controlled clinical studies are warranted to ultimately confirm its utility in the TBI and provide answers to these questions.
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Affiliation(s)
- Andrzej Dekundy
- Merz Therapeutics GmbH, Eckenheimer Landstraße 100, 60318 Frankfurt am Main, Germany; (A.D.); (A.S.)
| | - Gerald Pichler
- Department of Neurology, Albert-Schweitzer-Hospital Graz, Albert-Schweitzer-Gasse 36, 8020 Graz, Austria;
| | - Reda El Badry
- Department of Neurology and Psychiatry, Faculty of Medicine, Assiut University Hospital, Assiut University, Assiut 71526, Egypt;
| | - Astrid Scheschonka
- Merz Therapeutics GmbH, Eckenheimer Landstraße 100, 60318 Frankfurt am Main, Germany; (A.D.); (A.S.)
| | - Wojciech Danysz
- Danysz Pharmacology Consulting, Vor den Gärten 16, 61130 Nidderau, Germany
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Chegão A, Vicente Miranda H. Unveiling new secrets in Parkinson's disease: The glycatome. Behav Brain Res 2023; 442:114309. [PMID: 36706808 DOI: 10.1016/j.bbr.2023.114309] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/04/2023] [Accepted: 01/19/2023] [Indexed: 01/25/2023]
Abstract
We are witnessing a considerable increase in the incidence of Parkinson's disease (PD), which may be due to the general ageing of the population. While there is a plethora of therapeutic strategies for this disease, they still fail to arrest disease progression as they do not target and prevent the neurodegenerative process. The identification of disease-causing mutations allowed researchers to better dissect the underlying causes of this disease, highlighting, for example, the pathogenic role of alpha-synuclein. However, most PD cases are sporadic, which is making it hard to unveil the major causative mechanisms of this disease. In the recent years, epidemiological evidence suggest that type-2 diabetes mellitus (T2DM) individuals have higher risk and worst outcomes of PD, allowing to raise the hypothesis that some dysregulated processes in T2DM may contribute or even trigger the neurodegenerative process in PD. One major consequence of T2DM is the unprogrammed reaction between sugars, increased in T2DM, and proteins, a reaction named glycation. Pre-clinical reports show that alpha-synuclein is a target of glycation, and glycation potentiates its pathogenicity which contributes for the neurodegenerative process. Moreover, it triggers, anticipates, or aggravates several PD-like motor and non-motor complications. A given profile of proteins are differently glycated in diseased conditions, altering the brain proteome and leading to brain dysfunction and neurodegeneration. Herein we coin the term Glycatome as the profile of glycated proteins. In this review we report on the mechanisms underlying the association between T2DM and PD, with particular focus on the impact of protein glycation.
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Affiliation(s)
- Ana Chegão
- iNOVA4Health, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Hugo Vicente Miranda
- iNOVA4Health, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa, Portugal.
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Comparison of LC-MS 3 and LC-MRM Methods for Quantifying Amantadine and Its Application in Therapeutic Amantadine Monitoring in Human Plasma. Molecules 2022; 27:molecules27217619. [PMID: 36364446 PMCID: PMC9655109 DOI: 10.3390/molecules27217619] [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: 09/21/2022] [Revised: 10/28/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
A simple sample preprocessing method was developed for the quantitative determination of amantadine (AMT) in human plasma by liquid chromatography-tandem mass spectrometry cubed (LC-MS3). The LC-MS3 system comprised a Shimadzu Exion LC-20AD HPLC pump coupled with a QTRAP 5500 mass spectrometer. First, the plasma samples were pretreated using acetonitrile as the extracting solution to precipitate protein. Next, amantadine and amantadine-d15 (AMT-d15) were separated on an Agilent Poroshell 120 SB-C18 column (4.6 mm × 50 mm, 2.7 μm) using isocratic elution with solvent A (70% 0.1% formic acid) and solvent B (30% acetonitrile) at a flow rate of 0.8 mL/min. The total run time for each sample was 3 min. The system used triple-stage fragmentation transitions at m/z 152.2→135.3→107.4 for AMT quantification in the positive ion mode and m/z 167.0→150.3→118.1 for AMT-d15 quantification. The LC-MS3 assay was linear (r > 0.995) with a concentration range of 50−1500 ng/mL. The lower limit of quantification (LLOQ) was 50 ng/mL, and the intra-day and inter-day accuracies and precisions were less than 8.0% at all concentrations. In addition, the recoveries and matrix effect for AMT in human plasma were within acceptable limits. In terms of stability, AMT had no significant degradation under all conditions. All the results met the requirements of the guidelines of the Food and Drug Administration (FDA) for biological method validation. The novelty of the MS3 assay was that it presented a methodology with higher selectivity and sensitivity. This method was successfully applied to 44 human plasma samples, and the obtained quantitative results were compared with another liquid chromatography-multiple reaction monitoring (LC-MRM) method. The Passing-Bablok regression coefficients and Bland-Altman plot revealed no difference between the LC-MS3 and LC-MRM methods, implying that the developed LC-MS3 method is a reliable and accurate assay for AMT determination in human plasma. These results are also a proof of concept for determining chemicals in biological samples by the LC-MS3 strategy.
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Cohen SR, Terry ML, Coyle M, Wheelis E, Centner A, Smith S, Glinski J, Lipari N, Budrow C, Manfredsson FP, Bishop C. The multimodal serotonin compound Vilazodone alone, but not combined with the glutamate antagonist Amantadine, reduces l-DOPA-induced dyskinesia in hemiparkinsonian rats. Pharmacol Biochem Behav 2022; 217:173393. [DOI: 10.1016/j.pbb.2022.173393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/25/2022] [Accepted: 04/27/2022] [Indexed: 01/06/2023]
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Fridman EA, Schiff ND. Organizing a Rational Approach to Treatments of Disorders of Consciousness Using the Anterior Forebrain Mesocircuit Model. J Clin Neurophysiol 2022; 39:40-48. [PMID: 34474427 PMCID: PMC8900660 DOI: 10.1097/wnp.0000000000000729] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
SUMMARY Organizing a rational treatment strategy for patients with multifocal structural brain injuries and disorders of consciousness (DOC) is an important and challenging clinical goal. Among potential clinical end points, restoring elements of communication to DOC patients can support improved patient care, caregiver satisfaction, and patients' quality of life. Over the past decade, several studies have considered the use of the anterior forebrain mesocircuit model to approach this problem because this model proposes a supervening circuit-level impairment arising across DOC of varying etiologies. We review both the conceptual foundation of the mesocircuit model and studies of mechanisms underlying DOC that test predictions of this model. We consider how this model can guide therapeutic interventions and discuss a proposed treatment algorithm based on these ideas. Although the approach reviewed originates in the evaluation of patients with chronic DOC, we consider some emerging implications for patients in acute and subacute settings.
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Affiliation(s)
- Esteban A Fridman
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York, U.S.A
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Evaluation of Intraperitoneal [ 18F]-FDOPA Administration for Micro-PET Imaging in Mice and Assessment of the Effect of Subchronic Ketamine Dosing on Dopamine Synthesis Capacity. Mol Imaging 2022; 2022:4419221. [PMID: 36721730 PMCID: PMC9881672 DOI: 10.1155/2022/4419221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/08/2022] [Indexed: 02/05/2023] Open
Abstract
Positron emission tomography (PET) using the radiotracer [18F]-FDOPA provides a tool for studying brain dopamine synthesis capacity in animals and humans. We have previously standardised a micro-PET methodology in mice by intravenously administering [18F]-FDOPA via jugular vein cannulation and assessment of striatal dopamine synthesis capacity, indexed as the influx rate constant K i Mod of [18F]-FDOPA, using an extended graphical Patlak analysis with the cerebellum as a reference region. This enables a direct comparison between preclinical and clinical output values. However, chronic intravenous catheters are technically difficult to maintain for longitudinal studies. Hence, in this study, intraperitoneal administration of [18F]-FDOPA was evaluated as a less-invasive alternative that facilitates longitudinal imaging. Our experiments comprised the following assessments: (i) comparison of [18F]-FDOPA uptake between intravenous and intraperitoneal radiotracer administration and optimisation of the time window used for extended Patlak analysis, (ii) comparison of Ki Mod in a within-subject design of both administration routes, (iii) test-retest evaluation of Ki Mod in a within-subject design of intraperitoneal radiotracer administration, and (iv) validation of Ki Mod estimates by comparing the two administration routes in a mouse model of hyperdopaminergia induced by subchronic ketamine. Our results demonstrate that intraperitoneal [18F]-FDOPA administration resulted in good brain uptake, with no significant effect of administration route on Ki Mod estimates (intraperitoneal: 0.024 ± 0.0047 min-1, intravenous: 0.022 ± 0.0041 min-1, p = 0.42) and similar coefficient of variation (intraperitoneal: 19.6%; intravenous: 18.4%). The technique had a moderate test-retest validity (intraclass correlation coefficient (ICC) = 0.52, N = 6) and thus supports longitudinal studies. Following subchronic ketamine administration, elevated K i Mod as compared to control condition was measured with a large effect size for both methods (intraperitoneal: Cohen's d = 1.3; intravenous: Cohen's d = 0.9), providing further evidence that ketamine has lasting effects on the dopamine system, which could contribute to its therapeutic actions and/or abuse liability.
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Amantadine in the treatment of Parkinson's disease and other movement disorders. Lancet Neurol 2021; 20:1048-1056. [PMID: 34678171 DOI: 10.1016/s1474-4422(21)00249-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/14/2021] [Accepted: 07/21/2021] [Indexed: 11/24/2022]
Abstract
The efficacy of amantadine in the symptomatic treatment of patients with Parkinson's disease, discovered serendipitously more than 50 years ago, has stood the test of time and the drug is still commonly used by neurologists today. Its pharmacological actions are unique in combining dopaminergic and glutamatergic properties, which account for its dual effect on parkinsonian signs and symptoms and levodopa-induced dyskinesias. Furthermore, amantadine has additional and less well-defined pharmacological effects, including on anticholinergic and serotonergic activity. Evidence from randomised controlled trials over the past 5 years has confirmed the efficacy of amantadine to treat levodopa-induced dyskinesias in patients with Parkinson's disease, and clinical studies have also provided support for its potential to reduce motor fluctuations. Other uses of amantadine, such as in the treatment of drug-induced parkinsonism, atypical parkinsonism, Huntington's disease, or tardive dyskinesia, lack a strong evidence base. Future trials should examine its role in the management of motor and non-motor symptoms in patients with early Parkinson's disease and those with other movement disorders.
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Danysz W, Dekundy A, Scheschonka A, Riederer P. Amantadine: reappraisal of the timeless diamond-target updates and novel therapeutic potentials. J Neural Transm (Vienna) 2021; 128:127-169. [PMID: 33624170 PMCID: PMC7901515 DOI: 10.1007/s00702-021-02306-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/13/2021] [Indexed: 12/30/2022]
Abstract
The aim of the current review was to provide a new, in-depth insight into possible pharmacological targets of amantadine to pave the way to extending its therapeutic use to further indications beyond Parkinson's disease symptoms and viral infections. Considering amantadine's affinities in vitro and the expected concentration at targets at therapeutic doses in humans, the following primary targets seem to be most plausible: aromatic amino acids decarboxylase, glial-cell derived neurotrophic factor, sigma-1 receptors, phosphodiesterases, and nicotinic receptors. Further three targets could play a role to a lesser extent: NMDA receptors, 5-HT3 receptors, and potassium channels. Based on published clinical studies, traumatic brain injury, fatigue [e.g., in multiple sclerosis (MS)], and chorea in Huntington's disease should be regarded potential, encouraging indications. Preclinical investigations suggest amantadine's therapeutic potential in several further indications such as: depression, recovery after spinal cord injury, neuroprotection in MS, and cutaneous pain. Query in the database http://www.clinicaltrials.gov reveals research interest in several further indications: cancer, autism, cocaine abuse, MS, diabetes, attention deficit-hyperactivity disorder, obesity, and schizophrenia.
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Affiliation(s)
- Wojciech Danysz
- Merz Pharmaceuticals GmbH., Eckenheimer Landstraße 100, 60318, Frankfurt am Main, Germany
| | - Andrzej Dekundy
- Merz Pharmaceuticals GmbH., Eckenheimer Landstraße 100, 60318, Frankfurt am Main, Germany
| | - Astrid Scheschonka
- Merz Pharmaceuticals GmbH., Eckenheimer Landstraße 100, 60318, Frankfurt am Main, Germany
| | - Peter Riederer
- Clinic and Policlinic for Psychiatry, Psychosomatics and Psychotherapy, University Hospital Würzburg, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany.
- Department Psychiatry, University of Southern Denmark Odense, Vinslows Vey 18, 5000, Odense, Denmark.
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Amantadine enhances nigrostriatal and mesolimbic dopamine function in the rat brain in relation to motor and exploratory activity. Pharmacol Biochem Behav 2019; 179:156-170. [DOI: 10.1016/j.pbb.2018.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/11/2018] [Accepted: 12/27/2018] [Indexed: 01/01/2023]
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Perez-Lloret S, Rascol O. Efficacy and safety of amantadine for the treatment of L-DOPA-induced dyskinesia. J Neural Transm (Vienna) 2018; 125:1237-1250. [PMID: 29511826 DOI: 10.1007/s00702-018-1869-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 02/27/2018] [Indexed: 12/19/2022]
Abstract
L-DOPA induced dyskinesias (LIDs) may affect up to 40% of Parkinson's disease (PD) and impact negatively health-related quality of life. Amantadine has demonstrated significant antidyskinetic effects in animal PD models and in randomized double-blind placebo-controlled trials (RCTs) in patients with PD. These effects are thought to be related to the blockade of NMDA receptors modulating cortico-striatal glutamatergic-dopaminergic interactions involved in the genesis of LIDs. There are three pharmaceutical forms of amantadine currently available in the market: an oral immediate-release (IR) formulation, which is widely available; an extended-release (ER) formulation (ADS-5102) which has been recently developed and approved by the FDA; and an intravenous infusion (IV) solution, which is not commonly used in clinical practice. RCTs with amantadine IR or ER, involving more than 650 patients have shown consistent and long-lasting reductions in LIDs. Interestingly, ADS-5102 not only reduced LIDs, but also reduced significantly at the same time the duration of daily OFF-time, a unique finding compared with other antiparkinsonian medications that usually reduce time spent OFF at the cost of worsening of LIDs. Amantadine IR might also have possible effects on other PD symptoms such as apathy or fatigue. The most common adverse reactions with amantadine are constipation, cardiovascular dysfunction including QT prolongation, orthostatic hypotension and edema, neuropsychiatric symptoms such as hallucinations, confusion and delirium, nausea and livedo reticularis. Corneal degeneration is rare but critical. In summary, amantadine immediate and extended-release are effective and safe for the treatment of LIDs.
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Affiliation(s)
- Santiago Perez-Lloret
- Institute of Cardiology Research, University of Buenos Aires, National Research Council (CONICET-ININCA), Buenos Aires, Argentina
| | - Olivier Rascol
- University of Toulouse 3, CHU of Toulouse, Toulouse, France. .,INSERM, Department of Clinical Pharmacology and Neurosciences, Faculty of Medicine, Centre d'Investigation Clinique CIC1436, Centre Expert Parkinson de Toulouse, 37 Allées Jules Guesde, 31000, Toulouse, France. .,NeuroToul Center of Excellence in Neurodegeneration (COEN), Toulouse, France.
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Effect of N1-dansylspermine and Ro25,6981 on locomotor activity in naive mice and in the reserpinized mouse model of Parkinson’s disease. Neuroreport 2016; 27:1243-1247. [DOI: 10.1097/wnr.0000000000000685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Neuromodulation of the conscious state following severe brain injuries. Curr Opin Neurobiol 2014; 29:172-7. [PMID: 25285395 DOI: 10.1016/j.conb.2014.09.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/16/2014] [Accepted: 09/22/2014] [Indexed: 11/22/2022]
Abstract
Disorders of consciousness (DOC) following severe structural brain injuries globally affect the conscious state and the expression of goal-directed behaviors. In some subjects, neuromodulation with medications or electrical stimulation can markedly improve the impaired conscious state present in DOC. We briefly review recent studies and provide an organizing framework for considering the apparently widely disparate collection of medications and approaches that may modulate the conscious state in subjects with DOC. We focus on neuromodulation of the anterior forebrain mesocircuit in DOC and briefly compare mechanisms supporting recovery from structural brain injuries to those underlying facilitated emergence from unconsciousness produced by anesthesia. We derive some general principles for approaching the problem of restoration of consciousness after severe structural brain injuries, and suggest directions for future research.
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Faulkner MA. Safety overview of FDA-approved medications for the treatment of the motor symptoms of Parkinson's disease. Expert Opin Drug Saf 2014; 13:1055-69. [PMID: 24962891 DOI: 10.1517/14740338.2014.931369] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Parkinson's disease (PD) is among the most common of the neurodegenerative disorders. Treatment is primarily focused on correcting neurotransmitter imbalances. Several classes of medication are available for this purpose. AREAS COVERED A Medline search was performed to gather information about the safety of the medications approved for the treatment of the motor symptoms of PD. This was supplemented with additional articles obtained from online sources and information provided by the FDA and the manufacturers. The focus of this review is the side-effect and safety profiles of carbidopa/levodopa, dopamine agonists, selective monoamine oxidase inhibitors, catechol-o-methyltransferase inhibitors, anticholinergics and amantadine. EXPERT OPINION Though serious side-effects may occur, as a group, the medications used for the treatment of PD motor symptoms tend to produce side-effects that are mild to moderate in nature, and that primarily reflect the focus on dopaminergic therapies. Care plans for Parkinson's patients should be approached based on the needs of the individual as disease presentation, lifestyle, level of disability, concurrent disease states and the presence of non-motor symptoms make each case unique. Patients and caregivers must have realistic expectations about the use of PD medications.
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Affiliation(s)
- Michele A Faulkner
- Creighton University School of Pharmacy and Health Professions and School of Medicine , 2500 California Plaza, Omaha, NE 68178 , USA +1 402 280 3145 ;
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Vulnerability to psychotogenic effects of ketamine is associated with elevated D2/3-receptor availability. Int J Neuropsychopharmacol 2013; 16:745-54. [PMID: 22906553 DOI: 10.1017/s1461145712000764] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Previous positron emission tomography (PET) studies employing competition paradigms have shown either no change or substantial declines in striatal [(11)C]-raclopride binding after challenge with psychotogenic doses of the N-methyl-D-aspartate antagonist ketamine. We sought to probe the relationship between the severity of ketamine-induced psychotic symptoms and altered dopamine D(2/3) receptor availability throughout brain using the high affinity ligand [(18)F]-fallypride (FP). PET recordings were obtained in a group of 10 healthy, young male volunteers, in a placebo condition, and in the course of an infusion with ketamine at a psychotomimetic dose. Administration of the Positive and Negative Syndrome Scale and the Thought and Language Index in both conditions revealed a substantial emergence of mainly negative symptoms of schizophrenia, persisting until the end of the 3 h PET recordings. The baseline FP binding in cortex, caudate nucleus and other brain regions was highly predictive of the individual severity of psychotic symptoms in the ketamine condition. However, there was no evidence of ketamine-evoked reductions in FP binding. In the context of earlier findings, we speculate that high baseline D(2/3)-receptor availability may impart benefits with regard to cognitive flexibility, but increases the risk of maladaptive information processing in the face of environmental stresses and challenges.
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Variations of Aripiprazole-Induced Dyskinesia Existing with Concurrent Use of Amantadine and an Anticholinergic Agent in an Elderly Patient. INT J GERONTOL 2012. [DOI: 10.1016/j.ijge.2011.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Bido S, Marti M, Morari M. Amantadine attenuates levodopa-induced dyskinesia in mice and rats preventing the accompanying rise in nigral GABA levels. J Neurochem 2011; 118:1043-55. [PMID: 21740438 DOI: 10.1111/j.1471-4159.2011.07376.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Amantadine is the only drug marketed for treating levodopa-induced dyskinesia. However, its impact on basal ganglia circuitry in the dyskinetic brain, particularly on the activity of striatofugal pathways, has not been evaluated. We therefore used dual probe microdialysis to investigate the effect of amantadine on behavioral and neurochemical changes in the globus pallidus and substantia nigra reticulata of 6-hydroxydopamine hemi-lesioned dyskinetic mice and rats. Levodopa evoked abnormal involuntary movements (AIMs) in dyskinetic mice, and simultaneously elevated GABA release in substantia nigra reticulata (∼3-fold) but not globus pallidus. Glutamate levels were unaffected in both areas. Amantadine (40 mg/kg, i.p.), ineffective alone, attenuated (∼50%) AIMs expression and prevented the GABA rise. Moreover, it unraveled a facilitatory effect of levodopa on pallidal glutamate levels. Levodopa also evoked AIMs expression and a GABA surge (∼2-fold) selectively in the substantia nigra of dyskinetic rats. However, different from mice, glutamate levels rose simultaneously. Amantadine, ineffective alone, attenuated (∼50%) AIMs expression preventing amino acid increase and leaving unaffected pallidal glutamate. Overall, the data provide neurochemical evidence that levodopa-induced dyskinesia is accompanied by activation of the striato-nigral pathway in both mice and rats, and that the anti-dyskinetic effect of amantadine partly relies on the modulation of this pathway.
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Affiliation(s)
- Simone Bido
- Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara, Ferrara, Italy
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Akita H, Honda Y, Ogata M, Noda K, Saji M. Activation of the NMDA receptor involved in the alleviating after-effect of repeated stimulation of the subthalamic nucleus on motor deficits in hemiparkinsonian rats. Brain Res 2009; 1306:159-67. [PMID: 19766606 DOI: 10.1016/j.brainres.2009.09.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 09/09/2009] [Accepted: 09/11/2009] [Indexed: 10/20/2022]
Abstract
To test the hypothesis that the cellular mechanism whereby chronic deep brain stimulation of the subthalamic nucleus (STN-DBS) induces the improvement of motor deficits lasting after stimulation in the hemiparkinsonian (hemi-PD) rat involves the NMDA receptor-dependent processes in neurons receiving afferents from the STN, we examined whether the NMDA receptor antagonist prevents the alleviating after-effect of repeated STN-DBS on motor deficits in hemi-PD. The cylinder test was performed before and after repeated STN-DBS over 3 days in hemi-PD that received a unilateral injection of 6-OHDA into the medial forebrain bundle 3 weeks prior to STN-DBS experiments. No significant improvement in the reduced frequency of forelimb use and forelimb-use asymmetry was seen in the cylinder test after the single STN-DBS, while, when the STN-DBS was applied three times at intervals of 24 h, the improvement became apparent and significant only in the reduced frequency of forelimb use (akinesia) after termination of the stimulation, suggesting the alleviating after-effect of chronic stimulation. Then, the effects of intraperitoneal administration of the non-competitive NMDA receptor antagonist MK-801 and the competitive NMDA receptor antagonist CPP on the alleviating after-effect of the STN-DBS were examined in cylinder tests performed before and after repeated STN-DBS for 3 days in hemi-PD. Both MK-801 (0.1 mg/kg) and CPP (0.5 mg/kg) completely prevented the improvement of the akinetic motor deficit after repeated STN-DBS. These results support the hypothesis that activation of the NMDA receptor and subsequent cellular processes in neurons receiving the afferents from the STN may involve in the mechanism underlying the alleviating after-effect of chronic STN-DBS on the akinetic motor deficit in hemi-PD.
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Affiliation(s)
- Hisanao Akita
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara 228-8555, Japan
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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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Borghammer P, Vafaee M, Ostergaard K, Rodell A, Bailey C, Cumming P. Effect of memantine on CBF and CMRO2 in patients with early Parkinson's disease. Acta Neurol Scand 2008; 117:317-23. [PMID: 17927800 DOI: 10.1111/j.1600-0404.2007.00943.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Parkinson's disease (PD) may be associated with increased energy metabolism in overactive regions of the basal ganglia. Therefore, we hypothesized that treatment with the N-methyl-d-aspartate receptor (NMDAR) antagonist memantine would decrease regional cerebral blood flow (rCBF) and oxygen metabolism in the basal ganglia of patients with early-stage PD. METHODS Quantitative positron emission tomography (PET) recordings were obtained with 15O]water and 15O]oxygen in 10 patients, scanned first in a baseline condition, and again 6 weeks after treatment with a daily dose of 20 mg memantine. Dynamic PET data were analyzed using volume of interest and voxel-based approaches. RESULTS The treatment evoked rCBF decreases in basal ganglia, and in several frontal cortical areas. The regional cerebral metabolic rate of oxygen (rCMRO2) did not decrease in any of the a priori defined regions, and consequently the oxygen extraction fraction was increased in these regions. Two peaks of significantly decreased rCMRO2 were detected near the frontal poles in both hemispheres, using a posteriori voxel-based analysis. CONCLUSIONS Although we did not find the predicted decrease in basal ganglia oxygen consumption, our data suggest that treatment with memantine actively modulates neuronal activity and/or hemodynamic response in basal ganglia of PD patients. This finding may be relevant to the putative neuroprotective properties of NMDAR antagonists.
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Affiliation(s)
- P Borghammer
- PET Center, Aarhus University Hospital, Aarhus, Denmark.
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Storozhuk VM, Zinyuk LE. Specific features of sensorimotor cerebral cortex activity modulation by dopamine releaser amantadine. Exp Brain Res 2007; 182:157-67. [PMID: 17522851 DOI: 10.1007/s00221-007-0976-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Accepted: 04/27/2007] [Indexed: 10/23/2022]
Abstract
The modulatory effects of amantadine (1-adamantanamine) on the activity of sensorimotor cerebral cortex neurones during microiontophoretic application of agonists of glutamatergic and GABA-ergic (gamma-aminobutyric acid) transmission were studied. In non-anaesthetised cats, dopamine (DA) released by amantadine application in a small area of the neocortex increased baseline and evoked neuronal activity, providing stabilization and optimum course of both the neuronal and the conditioned responses of the animal. Amantadine eliminates a decrease in the level of neuronal baseline and evoked activity and marked increase in the latency of neuronal activation and conditioned movement mediated by D2 receptor antagonist sulpiride ((S)-5-aminosulfonyl-N-[(1-ethyl-2-pyrrolidinyl) methyl]-2-methoamantadineybenzamide) or GABA. This is reflected by a proportionate decrease in the onset of neuronal impulse reaction and latency of conditioned movement. Combined NMDA (N-methyl-D: -aspartate) and amantadine application also caused a considerable increase in baseline and evoked activity, but produced a slightly weaker effect than that evoked by NMDA application alone. A decrease in the baseline and evoked neuronal activity after NMDA withdrawn lasted during next control session (up to 40 min). The ability of DA releaser amantadine to alleviate significant increase in the latency of neuronal responses and conditioned movement induced by sulpiride or GABA suggests that dopamine modulates the activity of GABA-ergic inhibitory fast spike interneurons in the cat sensorimotor cortex during conditioning.
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Affiliation(s)
- Viktor M Storozhuk
- A.A.Bogomoletz Institute of Physiology, Academy of Sciences, Bogomoletz str.4, 010024 Kiev, Ukraine
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Reis J, John D, Heimeroth A, Mueller HH, Oertel WH, Arndt T, Rosenow F. Modulation of human motor cortex excitability by single doses of amantadine. Neuropsychopharmacology 2006; 31:2758-66. [PMID: 16794570 DOI: 10.1038/sj.npp.1301122] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Amantadine-sulfate has been used for several decades to treat acute influenza A, Parkinson's disease (PD), and acute or chronic drug-induced dyskinesia. Several mechanisms of actions detected in vivo/in vitro including N-methyl-D-aspartate (NMDA)-receptor antagonism, blockage of potassium channels, dopamine receptor agonism, enhancement of noradrenergic release, and anticholinergic effects have been described. We used transcranial magnetic stimulation (TMS) to evaluate the effect of single doses of amantadine on human motor cortex excitability in normal subjects. Using a double-blind, placebo-controlled, crossover study design, motor thresholds, recruitment curves, cortical stimulation-induced silent period (CSP), short intracortical inhibition (ICI), intracortical facilitation (ICF), and late inhibition (L-ICI) in 14 healthy subjects were investigated after oral doses of 50 and 100 mg amantadine with single and paired pulse TMS paradigms. Spinal cord excitability was investigated by distal latencies and M-amplitudes of the abductor digiti minimi muscle. After intake of amantadine, a significant dose-dependent decrease of ICF was noticed as well as a significant increase of L-ICI as compared to placebo. The effect on ICF and L-ICI significantly correlated with amantadine serum levels. ICI was slightly increased after amantadine intake, but the effect failed to be significant. Furthermore, amantadine had no significant effects on motor thresholds, MEP recruitment curves, CSP, or peripheral excitability. In conclusion, a low dose of amantadine is sufficient in modulating human motor cortex excitability. The decrease of ICF and increase of L-ICI may reflect glutamatergic modulation or a polysynaptic interaction of glutamatergic and GABA-ergic circuits. Although amantadine has several mechanisms of action, the NMDA-receptor antagonism seems to be the most relevant effect on cortical excitability. As L-ICI can be influenced by this type of drug, it may be an interesting parameter for studies of motor learning and use-dependent plasticity.
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Affiliation(s)
- Janine Reis
- Department of Neurology, Interdisciplinary Epilepsy Center, Philipps-University, Marburg, Germany
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23
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Vernaleken I, Kumakura Y, Cumming P, Buchholz HG, Siessmeier T, Stoeter P, Müller MJ, Bartenstein P, Gründer G. Modulation of [18F]fluorodopa (FDOPA) kinetics in the brain of healthy volunteers after acute haloperidol challenge. Neuroimage 2006; 30:1332-9. [PMID: 16439159 DOI: 10.1016/j.neuroimage.2005.11.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Revised: 11/03/2005] [Accepted: 11/09/2005] [Indexed: 11/23/2022] Open
Abstract
In animal studies, acute antipsychotic treatment was shown to enhance striatal DOPA-decarboxylase (DDC) activity. However, this phenomenon has not been demonstrated in humans by positron emission tomography (PET). Therefore, we investigated acute haloperidol effects on DDC activity in humans using [18F]fluorodopa (FDOPA) PET. Nine healthy volunteers were scanned with FDOPA in drug-free baseline conditions and after 3 days of haloperidol treatment (5 mg/day). A continuous performance test (CPT) was administered in both conditions. The net blood-brain clearance of FDOPA (K(in)app) in striatum, mesencephalon, and medial prefrontal cortex was calculated by volume-of-interest analysis. The macroparameter K(in)app is a composite of several kinetic terms defining the distribution volume of FDOPA in brain (V(e)D) and the relative activity of DOPA decarboxylase (k3D). Therefore, compartmental kinetic analysis was used to identify the physiological basis of the observed changes in K(in)app period. The magnitude of K(in)app was significantly increased in the putamen (18%) and mesencephalon (36%). Furthermore, V(e)D in the brain was increased by 15%. Increments of k3(D) in the basal ganglia did not attain statistical significance. The significant worsening of CPT results did not correlate with changes in FDOPA utilization. The present PET results indicate potentiation of FDOPA utilization in human basal ganglia by acute haloperidol treatment, apparently due to increased availability throughout the brain. The stimulation of DDC cannot be excluded due to insufficient statistical power in the estimation of k3(D) changes.
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Affiliation(s)
- Ingo Vernaleken
- Department of Psychiatry and Psychotherapy, RWTH Aachen University, Aachen, Germany.
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24
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Snijdelaar DG, van Rijn CM, Vinken P, Meert TF. Effects of pre-treatment with amantadine on morphine induced antinociception during second phase formalin responses in rats. Pain 2005; 119:159-167. [PMID: 16297559 DOI: 10.1016/j.pain.2005.09.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Revised: 09/19/2005] [Accepted: 09/29/2005] [Indexed: 10/25/2022]
Abstract
The clinically available NMDA-receptor antagonist drug, amantadine, has been shown to result in morphine sparing effects in humans after surgery. However, no data are available to describe the exact form of interaction. The present study aims to profile the possible effects of amantadine (0, 12.5, 25 or 50 mgkg(-1) i.p.) pre-treatment on morphine (0, 0.63, 1.25, 2.5 or 5 mgkg(-1) s.c.) induced antinociception in rats. The (automated) formalin test (5% formalin, 50 microl) was used to assess if amantadine enhances the antinociceptive activity of morphine. Possible motor impairment was assessed with a rotarod test. Morphine was measured in serum of amantadine or vehicle treated rats to search for possible pharmacokinetic interactions between amantadine and morphine. Isobolographic analysis provided evidence for a synergistic interaction between amantadine and morphine in the second phase of the formalin test. No evidence was found to indicate that amantadine induced motor impairment at the doses potentiating morphine during the second phase of the formalin test. There was no evidence for a pharmacokinetic interaction between amantadine and morphine. Since, the second phase of the formalin test is dependent on activation of the NMDA receptor system it is concluded that an antagonistic activity of amantadine at the NMDA receptor most likely contributes to the synergistic interaction observed between amantadine and morphine in rats.
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Affiliation(s)
- Dirk G Snijdelaar
- Department of Anesthesiology/Pain Centre, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands Department of Biological Psychology, Nijmegen Institute for Cognition and Information, Radboud University Nijmegen, Nijmegen, The Netherlands Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
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Gironell A, Kulisevsky J, Pascual-Sedano B, Flamarich D. Effect of amantadine in essential tremor: A randomized, placebo-controlled trial. Mov Disord 2005; 21:441-5. [PMID: 16229019 DOI: 10.1002/mds.20676] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
There is a need for new medication for essential tremor (ET). Preliminary evidence suggests that amantadine may be effective in the treatment of ET. We studied the effects of amantadine in a double-blind, cross-over, placebo-controlled trial in ET patients. Sixteen patients with ET received amantadine 100 mg b.i.d. and placebo for 15 days, with a 1-week wash-out period between treatments. Major evaluation outcomes consisted of a tremor clinical rating scale, accelerometric recordings, and a self-reported disability scale obtained before drug intake and on study days 1 and 15 of each treatment period. A two-way repeated measures analysis of variance (treatment, time) was applied. Any P value < 0.05 was considered significant. On day 15, amantadine did not demonstrate any significant efficacy in reducing tremor with respect to baseline in any tremor measures. An increase in postural tremor as an adverse effect of amantadine was referred by 37.5% of patients. Results from the present trial indicate amantadine at 100 mg b.i.d. is not effective as a treatment for ET.
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Affiliation(s)
- Alexandre Gironell
- Movement Disorders Unit, Department of Neurology, Sant Pau Hospital, Autonomous University of Barcelona, Catalonia, Spain
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26
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Abstract
Motor skills, once learned, need to be consolidated over time in order to become resistant to disruption or interference. In some instances, the consolidation phase can also include spontaneous gains in performance even in the absence of further rehearsal on a motor task. Clinical and behavioral evidence suggest that N-methyl-D-aspartate (NMDA)-receptor activity is required for motor learning acquisition and behavioral synaptic plasticity. However, the involvement of NMDA receptors in motor consolidation, leading to stabilization of the recently formed motor memory, has not yet been assessed in humans. To address this issue, we used post-training administration of amantadine, a low-affinity NMDA-receptor channel blocker. In a double-blind design, 200 mg of amantadine or a matching placebo was given orally to two different groups of 11 healthy young volunteers each. The subjects were tested twice 24 h apart, using a motor adaptation paradigm consisting of an eight-target-pointing task. Comparison of the mean performance levels on this task revealed that subjects in both groups improved their performance levels significantly on Day 2 compared to Day 1, regardless of the treatment administered. Our data indicate that amantadine failed to block motor learning consolidation in subjects that had already learned the motor adaptation task. Thus, although required in some stages (e.g. acquisition) of motor memory processes, the present results suggest that NMDA-receptor activation may not be essential for consolidation of motor adaptation in humans.
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Affiliation(s)
- A Hadj Tahar
- Department of Psychology, University of Montreal, Montreal, Quebec, Canada
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Kumakura Y, Danielsen EH, Reilhac A, Gjedde A, Cumming P. Levodopa effect on [18F]fluorodopa influx to brain: normal volunteers and patients with Parkinson's disease. Acta Neurol Scand 2004; 110:188-95. [PMID: 15285777 DOI: 10.1111/j.1600-0404.2004.00299.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Levodopa is the immediate precursor of dopamine and the substrate for DOPA decarboxylase, an enzyme subject to regulation in living brain. To test whether this regulation changes in disease, we used Positron Emission Tomography (PET) with parametric mapping to measure the effect of levodopa on the net clearance of [(18)F]fluorodopa to brain (K, ml/g/min). METHODS Five patients with early Parkinson's disease with pause of medication for 3 days and six age-matched healthy volunteers were studied in a baseline condition and after levodopa challenge. RESULTS Levodopa (200 mg as Sinemet) increased the magnitude of the net clearance K in the left and right putamen of the healthy volunteers by 11% relative to the baseline condition. In contrast, resumption of medication with levodopa did not significantly alter the magnitude of K in putamen of the Parkinson's disease patients. Compartmental analysis was used to probe the physiological basis of the activation of K: levodopa treatment increased by 15% the apparent distribution volume of [(18)F]fluorodopa in cerebellum (, ml/g) of both patients and control subjects, without significantly altering the unidirectional blood-brain clearance (, ml/g/min) or the relative activity of DOPA decarboxylase (, min(-1)) in putamen. CONCLUSION We conclude that levodopa treatment increases the distribution volume of [(18)F]fluorodopa in brain, increasing its availability for utilization in dopamine terminals. We speculate that levodopa act as a direct beta-adrenergic agonist at receptors regulating the permeability of the blood-brain barrier to levodopa. However, the PET analytical method was without sufficient power to detect the consequent increase in magnitude of K in brain of only five Parkinson's disease subjects.
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Affiliation(s)
- Y Kumakura
- PET Centre, Aarhus University Hospitals and Centre for Functionally Integrated Neuroscience, Aarhus, Denmark
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Vamvakidès A, Antoniou K, Daïfoti Z. Mécanisme d’action des effets anticonvulsivant et anti-immobilité (nage forcée) de la 3’, 4’-dihydro-N, N-diméthylspiro [9H-fluorène-9, 2’ (5’H)- furane] - 3’-méthanamine (AE37F). ANNALES PHARMACEUTIQUES FRANÇAISES 2004; 62:49-55. [PMID: 14747773 DOI: 10.1016/s0003-4509(04)94281-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AE37F, a new aminotetrahydrofuranic derivative, exhibited, at 10-30 mg/Kg (po) or 1-10 mg/Kg (ip), antagonism of tonic convulsions, induced by pentetrazole (130 mg/Kg, ip), and of forced swin immobility, in mice. At these doses AE37F induced a considerable (100-250%) increase of serotonin (5-HT) and its main metabolite, 5-hydroxyindolacetic acid (5-HIAA), in the rat nucleus reticularis pontis oralis (NRPO), antagonized by amantadine, which also increased 5-HT and 5-HIAA levels in the NRPO. It is suggested: a) that the anti-immobility effect of AE37F is related to its antimuscarinic properties, b) that the rate of 5-HT release in the NRPO, calculated here by a new approach (from the 5-HT and 5-HIAA brain levels) is increased by AE37F and decreased by amantadine, in the NRPO, c) that the anti-convulsant action, observed with AE37F, could be related to a NMDA-sigma mediated stimulation of serotoninergic, GABAergic and glycinergic brain neurones, antagonized by the NMDA-sigma inhibition induced by amantadine.
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Affiliation(s)
- A Vamvakidès
- Laboratoire de pharmacologie expérimentale, Faculté de médecine d'Athènes, Athènes, Grèce
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29
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Abstract
NMDA receptor antagonists impair learning and memory in animal models, presumably by inhibiting long-term potentiation in the motor cortex. Human studies are limited and restricted by the paucity of safe NMDA antagonists. Here, we investigated the contribution of glutamatergic neurotransmission to the capacity of acquiring motor-adaptation learning in humans. In a double-blind design, 200 mg of amantadine (a low-affinity NMDA receptor channel blocker) or a matching placebo were given orally to groups of 14 and 13 human healthy young volunteers, respectively. Blood samples were collected 3 h after treatment to assay plasma concentrations, and the subjects were then tested using a motor-adaptation paradigm consisting of an eight-target-pointing task. To rule out drug-related generalized impairments such sedation, tests measuring motor dexterity and attention were also administered pre- and post-treatment. Comparison of the mean performance levels on the motor-adaptation task revealed that subjects in the amantadine group performed at a lower level than those in the placebo group, but this difference did not reach significance. Interestingly, however, despite plasma amantadine concentrations being relatively low, ranging from 2.09 to 4.74 microM (mean=3.3 microM), they nevertheless correlated negatively with motor learning. Furthermore, when the amantadine group was divided into low-performance and high-performance subgroups, subjects in the former subgroup displayed mean amantadine concentrations 36% higher than the latter subgroup, and performed significantly worser than the placebo group. No change in performance was found on the motor-dexterity and attention tests. Altogether, our results lend support to the hypothesis that normal NMDA receptor function is necessary for the acquisition of motor adaptation.
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Affiliation(s)
- Abdallah Hadj Tahar
- Department of Psychology, University of Montreal, Downtown, Montreal, Que, Canada.
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Arai A, Kannari K, Shen H, Maeda T, Suda T, Matsunaga M. Amantadine increases L-DOPA-derived extracellular dopamine in the striatum of 6-hydroxydopamine-lesioned rats. Brain Res 2003; 972:229-34. [PMID: 12711097 DOI: 10.1016/s0006-8993(03)02531-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the effect of amantadine on L-DOPA-derived extracellular dopamine (DA) levels and aromatic L-amino acid decarboxylase (AADC) activity in the striatum of rats with nigrostriatal dopaminergic denervation by 6-hydroxydopamine (6-OHDA). Pretreatment with 30 mg/kg amantadine increased the cumulative amount of extracellular DA in the striatum of 6-OHDA-lesioned rats treated with 10 mg/kg benserazide and 50 mg/kg L-DOPA to 250% of that without amantadine (P<0.01). Under pretreatment with 10 mg/kg benserazide, AADC activity after 30 mg/kg amantadine administration was reduced to 43% of controls (P<0.01). Amantadine-induced increase in L-DOPA-derived extracellular DA provides the basis for the clinical usefulness of amantadine in combination with L-DOPA. However, the effect of amantadine on L-DOPA-derived extracellular DA may not be caused by changes in AADC activity.
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Affiliation(s)
- Akira Arai
- Department of Neurological Science, Institute of Brain Science, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki 036-8216, Japan
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Gründer G, Vernaleken I, Müller MJ, Davids E, Heydari N, Buchholz HG, Bartenstein P, Munk OL, Stoeter P, Wong DF, Gjedde A, Cumming P. Subchronic haloperidol downregulates dopamine synthesis capacity in the brain of schizophrenic patients in vivo. Neuropsychopharmacology 2003; 28:787-94. [PMID: 12655326 DOI: 10.1038/sj.npp.1300103] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The antipsychotic effect of neuroleptics cannot be attributed entirely to acute blockade of postsynaptic D(2)-like dopamine (DA) receptors, but may arise in conjunction with the delayed depolarization block of the presynaptic neurons and reduced DA synthesis capacity. Whereas the phenomenon of depolarization block is well established in animals, it is unknown if a similar phenomenon occurs in humans treated with neuroleptics. We hypothesized that haloperidol treatment should result in decreased DA synthesis capacity. We used 6-[(18)F]fluoro-L-dopa (FDOPA) and positron emission tomography (PET) in conjunction with compartmental modeling to measure the relative activity of DOPA decarboxylase (DDC) (k(D)(3), min(-1)) in the brain of nine unmedicated patients with schizophrenia, first in the untreated condition and again after treatment with haloperidol. Patients were administered psychometric rating scales at baseline and after treatment. Consistent with our hypothesis, there was a 25% decrease in the magnitude of k(D)(3) in both caudate and putamen following 5 weeks of haloperidol therapy. In addition, the magnitudes of k(D)(3) in cerebral cortex and thalamus were also decreased. Psychopathology as measured with standard rating scales improved significantly in all patients. The decrease of k(D)(3) in the thalamus was highly significantly correlated with the improvement of negative symptoms. Subchronic treatment with haloperidol decreased the activity of DDC in the brain of patients with schizophrenia. This observation is consistent with the hypothesis that the antipsychotic effect of chronic neuroleptic treatment is associated with a decrease in DA synthesis, reflecting a depolarization block of presynaptic DA neurons. We link an alteration in cerebral catecholamine metabolism in human brain with the therapeutic action of neuroleptic medication.
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Deleu D, Northway MG, Hanssens Y. Clinical pharmacokinetic and pharmacodynamic properties of drugs used in the treatment of Parkinson's disease. Clin Pharmacokinet 2002; 41:261-309. [PMID: 11978145 DOI: 10.2165/00003088-200241040-00003] [Citation(s) in RCA: 210] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Current research in Parkinson's disease (PD) focuses on symptomatic therapy and neuroprotective interventions. Drugs that have been used for symptomatic therapy are levodopa, usually combined with a peripheral decarboxylase inhibitor, synthetic dopamine receptor agonists, centrally-acting antimuscarinic drugs, amantadine, monoamine oxidase-B (MAO-B) inhibitors and catechol-O-methyltransferase (COMT) inhibitors. Drugs for which there is at least some evidence for neuroprotective effect are certain dopamine agonists, amantadine and MAO-B inhibitors (selegiline). Levodopa remains the most effective drug for the treatment of PD. Several factors contribute to the complex clinical pharmacokinetics of levodopa: erratic absorption, short half-life, peripheral O-methylation and facilitated transport across the blood-brain barrier. In patients with response fluctuations to levodopa, the concentration-effect curve becomes steeper and shifts to the right compared with patients with stable response. Pharmacokinetic-pharmacodynamic modelling can affect decisions regarding therapeutic strategies. The dopamine agonists include ergot derivatives (bromocriptine, pergolide, lisuride and cabergoline), non-ergoline derivatives (pramipexole, ropinirole and piribedil) and apomorphine. Most dopamine agonists have their specific pharmacological profile. They are used in monotherapy and as an adjunct to levodopa in early and advanced PD. Few pharmacokinetic and pharmacodynamic data are available regarding centrally acting antimuscarinic drugs. They are characterised by rapid absorption after oral intake, large volume of distribution and low clearance relative to hepatic blood flow, with extensive metabolism. The mechanism of action of amantadine remains elusive. It is well absorbed and widely distributed. Since elimination is primarily by renal clearance, accumulation of the drug can occur in patients with renal dysfunction and dosage reduction must be envisaged. The COMT inhibitors entacapone and tolcapone dose-dependently inhibit the formation of the major metabolite of levodopa, 3-O-methyldopa, and improve the bioavailability and reduce the clearance of levodopa without significantly affecting its absorption. They are useful adjuncts to levodopa in patients with end-of-dose fluctuations. The MAO-B inhibitor selegiline may have a dual effect: reducing the catabolism of dopamine and limiting the formation of neurotoxic free radicals. The pharmacokinetics of selegiline are highly variable; it has low bioavailability and large volume of distribution. The oral clearance is many-fold higher than the hepatic blood flow and the drug is extensively metabolised into several metabolites, some of them being active. Despite the introduction of several new drugs to the antiparkinsonian armamentarium, no single best treatment exists for an individual patient with PD. Particularly in the advanced stage of the disease, treatment should be individually tailored.
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Affiliation(s)
- Dirk Deleu
- College of Medicine, Sultan Qaboos University, PO Box 35, Al Khod, Sultanate of Oman.
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Taiminen T, Jääskeläinen SK. Intense and recurrent déjà vu experiences related to amantadine and phenylpropanolamine in a healthy male. J Clin Neurosci 2001; 8:460-2. [PMID: 11535020 DOI: 10.1054/jocn.2000.0810] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We report a case of a 39-year-old caucasian healthy male physician who developed intense and recurrent déjà vu experiences within 24h of initiating concomitant amantadine-phenylpropanolamine treatment against influenza. Déjà vu experiences terminated on discontinuation of medication. Findings in temporal epilepsy suggest that mesial temporal structures, including hippocampus, are related to paramnesic symptoms. On the other hand, previous case reports have confirmed that both amantadine and phenylpropanolamine alone, and particularly in combination, can induce psychotic symptoms due to their dopaminergic activity. The authors suggest that déjà vu experiences may be provoked by increased dopamine activity in mesial temporal structures of the brain.
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Affiliation(s)
- T Taiminen
- Department of Psychiatry, Turku University Central Hospital, Turku, Finland.
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Danielsen EH, Smith D, Hermansen F, Gjedde A, Cumming P. Acute neuroleptic stimulates DOPA decarboxylase in porcine brain in vivo. Synapse 2001; 41:172-5. [PMID: 11400183 DOI: 10.1002/syn.1071] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The activity of DOPA decarboxylase measured in homogenates from rat striatum, or calculated from the rate of tracer decarboxylation measured ex vivo, is stimulated following acute treatment with antagonists of dopamine D2-like receptors. We used compartmental kinetics to test the hypothesis that utilization of the DOPA decarboxylase substrate [(18)F]fluorodopa is potentiated in living striatum following acute treatment with a typical neuroleptic. The kinetics of the tracer uptake were determined in eight anesthetized female pigs (40 kg) and in three animals receiving an infusion of haloperidol (75 microg kg(-1) h(-1)) for 1 h prior to tracer administration and throughout the 2-h positron emission recording. The relative activity of DOPA decarboxylase in striatum was increased threefold by the treatment. This potentiation of DOPA decarboxylation after pharmacological blockade of dopamine D2-like receptors may be used to optimize the utilization of exogenous DOPA in the treatment of Parkinson's disease.
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Baezner H, Oster M, Henning O, Cohen S, Hennerici MG. Amantadine increases gait steadiness in frontal gait disorder due to subcortical vascular encephalopathy: a double-blind randomized placebo-controlled trial based on quantitative gait analysis. Cerebrovasc Dis 2001; 11:235-44. [PMID: 11306774 DOI: 10.1159/000047645] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In a randomized, double-blind placebo-controlled trial, 40 patients diagnosed as subcortical vascular encephalopathy (SVE) were given a daily dose of 500 ml i.v. amantadine vs. placebo for 5 days. Both groups were treated with physiotherapy on a daily basis. Quantitative gait analyses were performed at days 1 and 6 to evaluate gait steadiness from cadence, length of heel-to-toe movements, variability of centre of gravity (COG) and double support time. Both placebo- and amantadine-receiving patient groups showed mild improvement in gait parameters after study, which failed to show the superiority of amantadine, when comparing drug-induced changes between both groups. However, analysing the treatment effects from day 0 to day 6 in both groups separately, statistically significant changes could be found in the amantadine group for cadence, length of heel-to-toe movements in single support phase as well as for variability in double support phase and double support time (two-tailed paired t-test, p < 0.05), whereas in the placebo group, a statistically significant effect could only be seen for double support time (p < 0.05). In this small pilot study, amantadine tends to improve gait steadiness as evaluated by cadence, length of heel-to-toe movements in single support phase, variability in double support phase and double support time, in patients with moderate frontal gait disorder due to SVE. Improvements in the placebo group can be interpreted as physiotherapy effect, which improved gait steadiness slightly, however, this was statistically significant only for double support time.
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Affiliation(s)
- H Baezner
- Department of Neurology, University of Heidelberg, Klinikum Mannheim, Germany.
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