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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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Fessel J. Personalized, Precision Medicine to Cure Alzheimer's Dementia: Approach #1. Int J Mol Sci 2024; 25:3909. [PMID: 38612719 PMCID: PMC11012190 DOI: 10.3390/ijms25073909] [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: 02/14/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
The goal of the treatment for Alzheimer's dementia (AD) is the cure of dementia. A literature review revealed 18 major elements causing AD and 29 separate medications that address them. For any individual with AD, one is unlikely to discern which major causal elements produced dementia. Thus, for personalized, precision medicine, all causal elements must be treated so that each individual patient will have her or his causal elements addressed. Twenty-nine drugs cannot concomitantly be administered, so triple combinations of drugs taken from that list are suggested, and each triple combination can be administered sequentially, in any order. Ten combinations given over 13 weeks require 2.5 years, or if given over 26 weeks, they require 5.0 years. Such sequential treatment addresses all 18 elements and should cure dementia. In addition, any comorbid risk factors for AD whose first presence or worsening was within ±1 year of when AD first appeared should receive appropriate, standard treatment together with the sequential combinations. The article outlines a randomized clinical trial that is necessary to assess the safety and efficacy of the proposed treatments; it includes a triple-drug Rx for equipoise. Clinical trials should have durations of both 2.5 and 5.0 years unless the data safety monitoring board (DSMB) determines earlier success or futility since it is uncertain whether three or six months of treatment will be curative in humans, although studies in animals suggest that the briefer duration of treatment might be effective and restore defective neural tracts.
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Affiliation(s)
- Jeffrey Fessel
- Clinical Medicine, Department of Medicine, University of California, 2069 Filbert Street, San Francisco, CA 94123, USA
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MacLean MA, Muradov JH, Greene R, Van Hameren G, Clarke DB, Dreier JP, Okonkwo DO, Friedman A. Memantine inhibits cortical spreading depolarization and improves neurovascular function following repetitive traumatic brain injury. SCIENCE ADVANCES 2023; 9:eadj2417. [PMID: 38091390 PMCID: PMC10848720 DOI: 10.1126/sciadv.adj2417] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 11/14/2023] [Indexed: 12/18/2023]
Abstract
Cortical spreading depolarization (CSD) is a promising target for neuroprotective therapy in traumatic brain injury (TBI). We explored the effect of NMDA receptor antagonism on electrically triggered CSDs in healthy and brain-injured animals. Rats received either one moderate or four daily repetitive mild closed head impacts (rmTBI). Ninety-three animals underwent craniectomy with electrocorticographic (ECoG) and local blood flow monitoring. In brain-injured animals, ketamine or memantine inhibited CSDs in 44 to 88% and 50 to 67% of cases, respectively. Near-DC/AC-ECoG amplitude was reduced by 44 to 75% and 52 to 67%, and duration by 39 to 87% and 61 to 78%, respectively. Daily memantine significantly reduced spreading depression and oligemia following CSD. Animals (N = 31) were randomized to either memantine (10 mg/kg) or saline with daily neurobehavioral testing. Memantine-treated animals had higher neurological scores. We demonstrate that memantine improved neurovascular function following CSD in sham and brain-injured animals. Memantine also prevented neurological decline in a blinded, preclinical randomized rmTBI trial.
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Affiliation(s)
- Mark A. MacLean
- Division of Neurosurgery, Dalhousie University, Halifax, Canada
| | - Jamil H. Muradov
- Department of Medical Neuroscience, Dalhousie University, Halifax, Canada
| | - Ryan Greene
- Department of Medical Neuroscience, Dalhousie University, Halifax, Canada
| | - Gerben Van Hameren
- Department of Medical Neuroscience, Dalhousie University, Halifax, Canada
| | - David B. Clarke
- Division of Neurosurgery, Dalhousie University, Halifax, Canada
| | - Jens P. Dreier
- Center for Stroke Research Berlin, Charite University, Berlin, Germany
| | - David O. Okonkwo
- Division of Neurosurgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alon Friedman
- Division of Neurosurgery, Dalhousie University, Halifax, Canada
- Department of Medical Neuroscience, Dalhousie University, Halifax, Canada
- Departments of Brain and Cognitive Sciences, Physiology and Cell Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Bällgren F, Hammarlund-Udenaes M, Loryan I. Active Uptake of Oxycodone at Both the Blood-Cerebrospinal Fluid Barrier and The Blood-Brain Barrier without Sex Differences: A Rat Microdialysis Study. Pharm Res 2023; 40:2715-2730. [PMID: 37610619 PMCID: PMC10733202 DOI: 10.1007/s11095-023-03583-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 08/07/2023] [Indexed: 08/24/2023]
Abstract
BACKGROUND Oxycodone active uptake across the blood-brain barrier (BBB) is associated with the putative proton-coupled organic cation (H+/OC) antiporter system. Yet, the activity of this system at the blood-cerebrospinal fluid barrier (BCSFB) is not fully understood. Additionally, sex differences in systemic pharmacokinetics and pharmacodynamics of oxycodone has been reported, but whether the previous observations involve sex differences in the function of the H+/OC antiporter system remain unknown. The objective of this study was, therefore, to investigate the extent of oxycodone transport across the BBB and the BCSFB in female and male Sprague-Dawley rats using microdialysis. METHODS Microdialysis probes were implanted in the blood and two of the following brain locations: striatum and lateral ventricle or cisterna magna. Oxycodone was administered as an intravenous infusion, and dialysate, blood and brain were collected. Unbound partition coefficients (Kp,uu) were calculated to understand the extent of oxycodone transport across the blood-brain barriers. Non-compartmental analysis was conducted using Phoenix 64 WinNonlin. GraphPad Prism version 9.0.0 was used to perform t-tests, one-way and two-way analysis of variance followed by Tukey's or Šídák's multiple comparison tests. Differences were considered significant at p < 0.05. RESULTS The extent of transport at the BBB measured in striatum was 4.44 ± 1.02 (Kp,uu,STR), in the lateral ventricle 3.41 ± 0.74 (Kp,uu,LV) and in cisterna magna 2.68 ± 1.01 (Kp,uu,CM). These Kp,uu values indicate that the extent of oxycodone transport is significantly lower at the BCSFB compared with that at the BBB, but still confirm the presence of active uptake at both blood-brain interfaces. No significant sex differences were observed in neither the extent of oxycodone delivery to the brain, nor in the systemic pharmacokinetics of oxycodone. CONCLUSIONS The findings clearly show that active uptake is present at both the BCSFB and the BBB. Despite some underestimation of the extent of oxycodone delivery to the brain, CSF may be an acceptable surrogate of brain ISF for oxycodone, and potentially also other drugs actively transported into the brain via the H+/OC antiporter system.
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Affiliation(s)
- Frida Bällgren
- Translational Pharmacokinetics/Pharmacodynamics group (tPKPD), Department of Pharmacy, Uppsala University, Box 580, 75123, Uppsala, Sweden.
| | - Margareta Hammarlund-Udenaes
- Translational Pharmacokinetics/Pharmacodynamics group (tPKPD), Department of Pharmacy, Uppsala University, Box 580, 75123, Uppsala, Sweden
| | - Irena Loryan
- Translational Pharmacokinetics/Pharmacodynamics group (tPKPD), Department of Pharmacy, Uppsala University, Box 580, 75123, Uppsala, Sweden.
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Li J, Si B, Chao J, He J. Amantadine-associated delirium in patients with maintenance dialysis: Insomnia-associated recovery and uneven seasonal distribution. Medicine (Baltimore) 2023; 102:e34077. [PMID: 37390288 PMCID: PMC10313273 DOI: 10.1097/md.0000000000034077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/01/2023] [Indexed: 07/02/2023] Open
Abstract
Amantadine hydrochloride is a risky drug for triggering delirium in dialysis patients; however, it is often administered casually. Furthermore, little is known regarding the recovery and prognosis of dialysis patients with amantadine-associated delirium. Data of this retrospective cohort study were collected from a local hospital database for hospitalizations between January 2011 and December 2020. Patients were divided into 2 cohorts: early recovery (recovery within 14 days) and delayed recovery (recovery more than 14 days). The cases were analyzed together with the intermonth temperature using descriptive statistics. A Kaplan-Meier survival curve and binary logistic regression were applied for the analyses of prognoses and factors. A total of 57 patients were included in this study. The most common symptoms were hallucinations (45.61%) and muscle tremors (43.86%). Early recovery was observed in 63.16% of the patients. Only 3.51% of the cases occurred in local summer (June, July, and August). Better prognoses for survival (hazard ratio [HR] = 0.066, 95% confidence interval [95% CI] = 0.021-0.212) and hospitalization costs (7968.42 ± 3438.43 CNY vs 12852.38 ± 9361.13 CNY, P = .031) were observed in patients with early recovery than in those with delayed recovery. In the multivariate logistic regression adjusted by 1:1 propensity score matching, delayed recovery was independently caused by insomnia (P = .022, = 10.119, 95% CI = 1.403-72.990) and avoided in patients with urine volume over 300 mL (P = .029, = 0.018, 95% CI = 0.006-0.621). The increment (per 100 mg) of cumulative dose (P = .190, = 1.588, 95% CI = 0.395-3.172) tended to be a risk of delayed recovery. The area under curve of the receiver operating characteristic curve was 0.867, with a sensitivity of 90.5% and a specificity of 82.4% at the cutoff point (cutoff = 0.432). For amantadine-associated delirium in dialysis patients with uneven seasonal distribution, early recovery with better prognosis should be the aim of treatment by giving priority to the remedy of insomnia.
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Affiliation(s)
- Jing Li
- Department of Nephrology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Bolin Si
- Department of Nephrology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Jun Chao
- Department of Nephrology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Jianqiang He
- Department of Nephrology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
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Saleh MAA, Bloemberg JS, Elassaiss-Schaap J, de Lange ECM. Drug Distribution in Brain and Cerebrospinal Fluids in Relation to IC 50 Values in Aging and Alzheimer's Disease, Using the Physiologically Based LeiCNS-PK3.0 Model. Pharm Res 2022; 39:1303-1319. [PMID: 35606598 PMCID: PMC9246802 DOI: 10.1007/s11095-022-03281-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/27/2022] [Indexed: 12/02/2022]
Abstract
Background Very little knowledge exists on the impact of Alzheimer’s disease on the CNS target site pharmacokinetics (PK). Aim To predict the CNS PK of cognitively healthy young and elderly and of Alzheimer’s patients using the physiologically based LeiCNS-PK3.0 model. Methods LeiCNS-PK3.0 was used to predict the PK profiles in brain extracellular (brainECF) and intracellular (brainICF) fluids and cerebrospinal fluid of the subarachnoid space (CSFSAS) of donepezil, galantamine, memantine, rivastigmine, and semagacestat in young, elderly, and Alzheimer’s patients. The physiological parameters of LeiCNS-PK3.0 were adapted for aging and Alzheimer’s based on an extensive literature search. The CNS PK profiles at plateau for clinical dose regimens were related to in vitro IC50 values of acetylcholinesterase, butyrylcholinesterase, N-methyl-D-aspartate, or gamma-secretase. Results The PK profiles of all drugs differed between the CNS compartments regarding plateau levels and fluctuation. BrainECF, brainICF and CSFSAS PK profile relationships were different between the drugs. Aging and Alzheimer’s had little to no impact on CNS PK. Rivastigmine acetylcholinesterase IC50 values were not reached. Semagacestat brain PK plateau levels were below the IC50 of gamma-secretase for half of the interdose interval, unlike CSFSAS PK profiles that were consistently above IC50. Conclusion This study provides insights into the relations between CNS compartments PK profiles, including target sites. CSFSAS PK appears to be an unreliable predictor of brain PK. Also, despite extensive changes in blood-brain barrier and brain properties in Alzheimer’s, this study shows that the impact of aging and Alzheimer’s pathology on CNS distribution of the five drugs is insignificant. Supplementary Information The online version contains supplementary material available at 10.1007/s11095-022-03281-3.
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Affiliation(s)
- Mohammed A A Saleh
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Julia S Bloemberg
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Jeroen Elassaiss-Schaap
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
- PD-value B.V., Houten, The Netherlands
| | - Elizabeth C M de Lange
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands.
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Lee PY, Lai YH, Liu PL, Liu CC, Su CC, Chiu FY, Cheng WC, Hsu SL, Cheng KC, Chiu LY, Kao TE, Lin CC, Chang YC, Wang SC, Li CY. Toxicity of amantadine hydrochloride on cultured bovine cornea endothelial cells. Sci Rep 2021; 11:18514. [PMID: 34531501 PMCID: PMC8445916 DOI: 10.1038/s41598-021-98005-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/01/2021] [Indexed: 12/02/2022] Open
Abstract
Amantadine hydrochloride (HCl) is commonly prescribed for treating influenza A virus infection and Parkinson's disease. Recently, several studies have indicated that the use of amantadine HCl is associated with corneal edema; however, the cytotoxic effect of amantadine HCl has not been investigated. In the present study, the effects of amantadine HCl on cell growth, proliferation, and apoptosis in bovine cornea endothelial cells, and in vitro endothelial permeability were examined. Results showed that lower doses of amantadine HCl do not affect cell growth (≤ 20 μΜ), whereas higher doses of amantadine HCl inhibits cell growth (≥ 50 μΜ), induces apoptosis (2000 μΜ), increases sub-G1 phase growth arrest (2000 μΜ), causes DNA damage (≥ 1000 μΜ), and induces endothelial hyperpermeability (≥ 1000 μΜ) in bovine cornea endothelial cells; additionally, we also found that amantadine HCl attenuates the proliferation (≥ 200 μΜ) and arrests cell cycle at G1 phase (≥ 200 μΜ) in bovine cornea endothelial cells. In the present study, we measured the cytotoxic doses of amantadine HCl on cornea endothelial cells, which might be applied in evaluating the association of corneal edema.
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Affiliation(s)
- Po-Yen Lee
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Yu-Hung Lai
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Po-Len Liu
- Department of Respiratory Therapy, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Ching-Chih Liu
- Department of Ophthalmology, Chi Mei Medical Center, Tainan, 71004, Taiwan
| | - Chia-Cheng Su
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Division of Urology, Department of Surgery, Chi-Mei Medical Center, Tainan, 71004, Taiwan
- Department of Senior Citizen Service Management, Chia Nan University of Pharmacy and Science, Tainan, 71710, Taiwan
| | - Fang-Yen Chiu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Wei-Chung Cheng
- Graduate Institute of Biomedical Sciences, and Research Center for Tumor Medical Science, and Drug Development Center, China Medical University, Taichung, 40402, Taiwan
| | - Shiuh-Liang Hsu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Kai-Chun Cheng
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, Kaohsiung Municipal Siaogang Hospital, Kaohsiung, 81267, Taiwan
| | - Li-Yi Chiu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung, 80145, Taiwan
| | - Tzu-En Kao
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Chia-Ching Lin
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Yo-Chen Chang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
- Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Shu-Chi Wang
- Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.
- Center for Cancer Research, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.
| | - Chia-Yang Li
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.
- Center for Cancer Research, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.
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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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Panthee N, Ono M, Yamamoto T, Ikemura M, Tanaka T, Itoda Y, Suzuki H. Evaluation of spinal cord protective threshold of serum memantine, an NMDA receptor antagonist, in a rabbit model of paraplegia. Indian J Thorac Cardiovasc Surg 2020; 36:598-607. [PMID: 33100621 DOI: 10.1007/s12055-020-01026-8] [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: 05/14/2020] [Revised: 07/21/2020] [Accepted: 07/28/2020] [Indexed: 11/27/2022] Open
Abstract
Purpose To evaluate the threshold of serum memantine for prevention of spinal cord injury (SCI) in a rabbit paraplegic model. Methods Forty-two New Zealand white rabbits were divided into 7 groups. Preoperatively, oral memantine was given starting from 60 mg OD for 7 days in the initial group, then reducing the dose and/or duration to 60 mg OD for 5 days, 30 mg OD for 5 days, 30 mg OD for 3 days, 15 mg OD for 3 days, 30 mg single dose, and 60 mg single dose, in subsequent 6 groups. A paraplegic model was created by clamping both infrarenal aorta and inferior vena cava (IVC) for 45 min. Motor evoked potentials (MEPs), modified Tarlov score (0-5), serum memantine concentration, and histopathology of the spinal cord were evaluated. Results Half of all rabbits (21/42) showed spinal protection. Receiver operating characteristic (ROC) curve analysis showed serum level of 4.5 ng/ml as a cutoff value for spinal protection (sensitivity 86%, specificity 62%, area under the curve (AUC) 0.785, P = .002). Sixteen rabbits had serum level ≥ 4.5 ng/ml (group A), with 26 rabbits having < 4.5 ng/ml (group B). Further comparison was done between groups A and B. The mean modified Tarlov score at 6, 24, 48, and 72 h was 4.5 ± 0.9 and 2.4 ± 1.6, in groups A and B, respectively (P < .001). The modified Tarlov score showed positive correlation with serum memantine level (Spearman's rho = 0.618, P = .01). Results of MEP and histopathology were significantly better for group A. Conclusions We showed that memantine is protective against SCI at serum levels ≥ 4.5 ng/ml in a rabbit model; thus, it can be a potential adjunct for spinal protection during thoracic/thoracoabdominal aortic surgeries.
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Affiliation(s)
- Nirmal Panthee
- Department of Cardiac Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Minoru Ono
- Department of Cardiac Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Takehito Yamamoto
- Department of Pharmacy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Masako Ikemura
- Department of Neuropathology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Tsuruhito Tanaka
- Department of Cardiac Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Yoshifumi Itoda
- Department of Cardiac Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
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10
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Kikuchi T. Is Memantine Effective as an NMDA-Receptor Antagonist in Adjunctive Therapy for Schizophrenia? Biomolecules 2020; 10:biom10081134. [PMID: 32751985 PMCID: PMC7466074 DOI: 10.3390/biom10081134] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/28/2020] [Accepted: 07/28/2020] [Indexed: 01/07/2023] Open
Abstract
Memantine, an n-methyl-d-aspartate (NMDA) receptor antagonist approved for treating Alzheimer's disease, has a good safety profile and is increasingly being studied for possible use in a variety of non-dementia psychiatric disorders. There is an abundance of basic and clinical data that support the hypothesis that NMDA receptor hypofunction contributes to the pathophysiology of schizophrenia. However, there are numerous randomized, double-blind, placebo-controlled clinical trials showing that add-on treatment with memantine improves negative and cognitive symptoms, particularly the negative symptoms of schizophrenia, indicating that memantine as adjunctive therapy in schizophrenia helps to ameliorate negative symptoms and cognitive deficits. It remains unclear why memantine does not show undesirable central nervous system (CNS) side effects in humans unlike other NMDA receptor antagonists, such as phencyclidine and ketamine. However, the answer could lie in the fact that it would appear that memantine works as a low-affinity, fast off-rate, voltage-dependent, and uncompetitive antagonist with preferential inhibition of extrasynaptic receptors. It is reasonable to assume that the effects of memantine as adjunctive therapy on negative symptoms and cognitive deficits in schizophrenia may derive primarily, if not totally, from its NMDA receptor antagonist activity at NMDA receptors including extrasynaptic receptors in the CNS.
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Affiliation(s)
- Tetsuro Kikuchi
- New Drug Research Division, Pharmaceutical Business Division, Otsuka Pharmaceutical Co., Ltd., 463-10 Kagasuno, Kawauchi-cho, Tokushima 771-0192, Japan
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11
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Abrahamson EE, Poloyac SM, Dixon CE, Dekosky ST, Ikonomovic MD. Acute and chronic effects of single dose memantine after controlled cortical impact injury in adult rats. Restor Neurol Neurosci 2020; 37:245-263. [PMID: 31177251 DOI: 10.3233/rnn-190909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Altered glutamatergic neurotransmission after traumatic brain injury (TBI) contributes to excitotoxic cell damage and death. Prevention or suppression of such changes is a desirable goal for treatment of TBI. Memantine (3,5-dimethyl-1-adamantanamine), an uncompetitive NMDA receptor antagonist with voltage-dependent open channel blocking kinetics, was reported to be neuroprotective in preclinical models of excitotoxicity, brain ischemia, and in TBI when administered prophylactically, immediately, or within minutes after injury. METHODS The current study examined effects of memantine administered by single intraperitoneal injection to adult male rats at a more clinically relevant delay of one hour after moderate-severe controlled cortical impact (CCI) injury or sham surgery. Histopathology was assessed on days 1, 7, 21, and 90, vestibulomotor function (beam balance and beam walk) was assessed on days 1-5 and 71-75, and spatial memory (Morris water maze test, MWM) was assessed on days 14-21 and 83-90 after CCI injury or sham surgery. RESULTS When administered at 10 mg/kg, but not 2.5 or 5 mg/kg, memantine preserved cortical tissue and reduced neuronal degeneration 1 day after injury, and attenuated loss of synaptophysin immunoreactivity in the hippocampus 7 days after injury. No effects of 10 mg/kg memantine were observed on histopathology at 21 and 90 days after CCI injury or sham surgery, or on vestibulomotor function and spatial memory acquisition assessed during any of the testing periods. However, 10 mg/kg memantine resulted in trends for improved search strategy in the MWM memory retention probe trial. CONCLUSIONS Administration of memantine at a clinically-relevant delay after moderate-severe CCI injury has beneficial effects on acute outcomes, while more significant improvement on subacute and chronic outcomes may require repeated drug administration or its combination with another therapy.
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Affiliation(s)
- Eric E Abrahamson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh PA, USA.,Department of Neurology, University of Pittsburgh, Pittsburgh PA, USA
| | - Samuel M Poloyac
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh PA, USA
| | - C Edward Dixon
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh PA, USA.,Department of Neurosurgery, University of Pittsburgh, Pittsburgh PA, USA
| | - Steven T Dekosky
- Department of Neurology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Milos D Ikonomovic
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh PA, USA.,Department of Neurology, University of Pittsburgh, Pittsburgh PA, USA.,Department of Psychiatry, University of Pittsburgh, Pittsburgh PA, USA
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Okada M, Fukuyama K, Kawano Y, Shiroyama T, Ueda Y. Memantine protects thalamocortical hyper-glutamatergic transmission induced by NMDA receptor antagonism via activation of system xc<sup/>. Pharmacol Res Perspect 2019; 7:e00457. [PMID: 30631447 PMCID: PMC6323135 DOI: 10.1002/prp2.457] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 12/14/2018] [Indexed: 12/26/2022] Open
Abstract
Deficiencies in N-methyl-d-aspartate (NMDA)/glutamate receptor (NMDAR) signaling have been considered central to the cognitive impairments of schizophrenia; however, an NMDAR antagonist memantine (MEM) improves cognitive impairments of Alzheimer's disease and schizophrenia. These mechanisms of paradoxical clinical effects of NMDAR antagonists remain unclear. To explore the mechanisms by which MK801 and MEM affect thalamocortical transmission, we determined interactions between local administrations of MK801, MEM, system xc- (Sxc), and metabotropic glutamate receptors (mGluRs) on extracellular glutamate and GABA levels in the mediodorsal thalamic nucleus (MDTN) and medial prefrontal cortex (mPFC) using dual-probe microdialysis with ultra-high-pressure liquid chromatography. Effects of MK801 and MEM on Sxc activity were also determined using primary cultured astrocytes. Sxc activity was enhanced by MEM, but was unaffected by MK801. MK801 enhanced thalamocortical glutamatergic transmission by GABAergic disinhibition in the MDTN. In the MDTN and the mPFC, MEM weakly increased glutamate release by activating Sxc, whereas MEM inhibited thalamocortical glutamatergic transmission. Paradoxical effects of MEM were induced following secondary activation of inhibitory II-mGluR and III-mGluR by exporting glutamate from astroglial Sxc. The present results suggest that the effects of therapeutically relevant concentrations of MEM on thalamocortical glutamatergic transmission are predominantly caused by activation of Sxc rather than inhibition of NMDAR. These demonstrations suggest that the combination between reduced NMDAR and activated Sxc contribute to the neuroprotective effects of MEM. Furthermore, activation of Sxc may compensate for the cognitive impairments that are induced by hyperactivation of thalamocortical glutamatergic transmission following activation of Sxc/II-mGluR in the MDTN and Sxc/II-mGluR/III-mGluR in the mPFC.
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Affiliation(s)
- Motohiro Okada
- Department of NeuropsychiatryDivision of NeuroscienceGraduate School of MedicineMie UniversityTsuMieJapan
| | - Kouji Fukuyama
- Department of NeuropsychiatryDivision of NeuroscienceGraduate School of MedicineMie UniversityTsuMieJapan
| | - Yasuhiro Kawano
- Department of NeuropsychiatryDivision of NeuroscienceGraduate School of MedicineMie UniversityTsuMieJapan
| | - Takashi Shiroyama
- Department of NeuropsychiatryDivision of NeuroscienceGraduate School of MedicineMie UniversityTsuMieJapan
| | - Yuto Ueda
- Department of NeuropsychiatryDivision of NeuroscienceGraduate School of MedicineMie UniversityTsuMieJapan
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13
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Gustafsson S, Lindström V, Ingelsson M, Hammarlund-Udenaes M, Syvänen S. Intact blood-brain barrier transport of small molecular drugs in animal models of amyloid beta and alpha-synuclein pathology. Neuropharmacology 2018; 128:482-491. [DOI: 10.1016/j.neuropharm.2017.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/04/2017] [Accepted: 08/03/2017] [Indexed: 01/19/2023]
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14
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Ito K, Tatebe T, Suzuki K, Hirayama T, Hayakawa M, Kubo H, Tomita T, Makino M. Memantine reduces the production of amyloid-β peptides through modulation of amyloid precursor protein trafficking. Eur J Pharmacol 2017; 798:16-25. [PMID: 28167259 DOI: 10.1016/j.ejphar.2017.02.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/31/2017] [Accepted: 02/02/2017] [Indexed: 01/30/2023]
Abstract
Memantine, an uncompetitive glutamatergic N-methyl-D-aspartate (NMDA) receptor antagonist, is widely used as medication for the treatment of Alzheimer's disease (AD). It has been reported that memantine reduces amyloid-β peptide (Aβ) levels in both neuronal cultures and in brains of animal models of AD. However, the underlying mechanism of these effects is unclear. Here we examined the effect of memantine on Aβ production. Memantine was administered to 9-month-old Tg2576 mice, a transgenic mouse model of AD, at 10 or 20mg/kg/day in drinking water for 1 month. Memantine significantly reduced the amounts of both CHAPS-soluble and CHAPS-insoluble Aβ in the brains of Tg2576 mice. Memantine at 10mg/kg/day for 1 month also reduced the levels of insoluble Aβ42 in the brains of aged F344 rats. Moreover, memantine reduced Aβ and sAPPβ levels in conditioned media from rat primary cortical cultures without affecting the enzymatic activities of α-secretase, β-secretase, or γ-secretase. Notably, in a cell-surface biotinylation assay, memantine increased the amount of amyloid precursor protein (APP) at the cell surface without changing the total amount of APP. Collectively, our results indicate that chronic treatment with memantine reduces the levels of Aβ both in AD models and in aged animals, and that memantine affects the endocytosis pathway of APP, which is required for β-secretase-mediated cleavage. This leads to a reduction in Aβ production. These results suggest that memantine reduces Aβ production and plaque deposition through the regulation of intracellular trafficking of APP.
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Affiliation(s)
- Kaori Ito
- Venture Science Laboratories, R&D Division, Daiichi-Sankyo Co. Ltd., Tokyo 140-8710, Japan.
| | - Takuya Tatebe
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Kunimichi Suzuki
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Takashi Hirayama
- Biological Research Department, Daiichi Sankyo RD Novare Co. Ltd., Tokyo 134-8630, Japan.
| | - Maki Hayakawa
- Biological Research Department, Daiichi Sankyo RD Novare Co. Ltd., Tokyo 134-8630, Japan.
| | - Hideo Kubo
- Biological Research Department, Daiichi Sankyo RD Novare Co. Ltd., Tokyo 134-8630, Japan.
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Mitsuhiro Makino
- Venture Science Laboratories, R&D Division, Daiichi-Sankyo Co. Ltd., Tokyo 140-8710, Japan.
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Suzuki T, Aoyama T, Suzuki N, Kobayashi M, Fukami T, Matsumoto Y, Tomono K. Involvement of a proton-coupled organic cation antiporter in the blood-brain barrier transport of amantadine. Biopharm Drug Dispos 2016; 37:323-35. [PMID: 27146715 DOI: 10.1002/bdd.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/09/2016] [Accepted: 05/01/2016] [Indexed: 01/18/2023]
Abstract
The blood-to-brain transport of amantadine, a weak N-methyl-d-aspartate (NMDA) antagonist, has been shown previously to participate in the cationic drug-sensitive transport system across the mouse blood-brain barrier (BBB). The purpose of the present study was to characterize the influx transport system by means of both an in situ mouse brain perfusion technique and in vitro studies using rat immortalized brain capillary endothelial cells (GPNT). The observed concentration-dependent initial uptake rate of [(3) H]amantadine suggested the involvement of a carrier-mediated transport mechanism. The normal uptake at physiological pH 7.4 was decreased by 72.9% in acidic perfusate, while it was increased by 35.3% in alkaline perfusate. These results suggest that pH-dependent transport is regulated by utilizing an oppositely directed proton gradient as a driving force. In addition, the [(3) H]amantadine uptake was moderately inhibited by the adamantane structural analogs (rimantadine and memantine) and other cationic drugs (pyrilamine, clonidine, nicotine, etc.), but not by substrates or inhibitors of the well-characterized organic cation transporters (tetraethylammonium, l-carnitine and choline). A similar inhibition pattern was observed between the in vivo studies and the in vitro experiments. These results indicate that the influx transport for amantadine across the BBB involves a proton-coupled organic cation antiporter. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Toyofumi Suzuki
- Laboratory of Pharmaceutics, School of Pharamcy, Nihon University, 7-7-1 Narashinodai, Funabashi, Chiba 274-8555, Japan.
| | - Takahiko Aoyama
- Laboratory of Clinical Pharmacokinetics, School of Pharamcy, Nihon University, 7-7-1 Narashinodai, Funabashi, Chiba 274-8555, Japan
| | - Naoto Suzuki
- Laboratory of Pharmaceutics, School of Pharamcy, Nihon University, 7-7-1 Narashinodai, Funabashi, Chiba 274-8555, Japan
| | - Masaru Kobayashi
- Nihon Pharmaceutical University, Kita-adachi, Saitama, 362-0806, Japan
| | - Toshiro Fukami
- Department of Molecular Pharmaceutics, Meiji Pharmaceutical University, Kiyose, Tokyo, 204-8588, Japan
| | - Yoshiaki Matsumoto
- Laboratory of Clinical Pharmacokinetics, School of Pharamcy, Nihon University, 7-7-1 Narashinodai, Funabashi, Chiba 274-8555, Japan
| | - Kazuo Tomono
- Laboratory of Pharmaceutics, School of Pharamcy, Nihon University, 7-7-1 Narashinodai, Funabashi, Chiba 274-8555, Japan
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Huang L, Yang XJ, Huang Y, Sun EY, Sun M. Ketamine Protects Gamma Oscillations by Inhibiting Hippocampal LTD. PLoS One 2016; 11:e0159192. [PMID: 27467732 PMCID: PMC4965035 DOI: 10.1371/journal.pone.0159192] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/28/2016] [Indexed: 12/02/2022] Open
Abstract
NMDA receptors have been widely reported to be involved in the regulation of synaptic plasticity through effects on long-term potentiation (LTP) and long-term depression (LTD). LTP and LTD have been implicated in learning and memory processes. Besides synaptic plasticity, it is known that the phenomenon of gamma oscillations is critical in cognitive functions. Synaptic plasticity has been widely studied, however it is still not clear, to what degree synaptic plasticity regulates the oscillations of neuronal networks. Two NMDA receptor antagonists, ketamine and memantine, have been shown to regulate LTP and LTD, to promote cognitive functions, and have even been reported to bring therapeutic effects in major depression and Alzheimer’s disease respectively. These compounds allow us to investigate the putative interrelationship between network oscillations and synaptic plasticity and to learn more about the mechanisms of their therapeutic effects. In the present study, we have identified that ketamine and memantine could inhibit LTD, without impairing LTP in the CA1 region of mouse hippocampus, which may underlie the mechanism of these drugs’ therapeutic effects. Our results suggest that NMDA-induced LTD caused a marked loss in the gamma power, and pretreatment with 10 μM ketamine prevented the oscillatory loss via its inhibitory effect on LTD. Our study provides a new understanding of the role of NMDA receptors on hippocampal plasticity and oscillations.
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Affiliation(s)
- Lanting Huang
- Neurodegeneration Discovery Performance Unit, GSK, R&D Shanghai, Building 1, 917 Halei Road, Zhangjiang Hi-tech Park, Pudong, Shanghai, China
- Stem Cell Translational Research Center, Tongji Hospital, School of Medicine, Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, China
| | - Xiu-Juan Yang
- Neurodegeneration Discovery Performance Unit, GSK, R&D Shanghai, Building 1, 917 Halei Road, Zhangjiang Hi-tech Park, Pudong, Shanghai, China
| | - Ying Huang
- Department of Physiology and Pathophysiology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Eve Y. Sun
- Stem Cell Translational Research Center, Tongji Hospital, School of Medicine, Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, China
| | - Mu Sun
- Neurodegeneration Discovery Performance Unit, GSK, R&D Shanghai, Building 1, 917 Halei Road, Zhangjiang Hi-tech Park, Pudong, Shanghai, China
- * E-mail:
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Kitamura A, Okura T, Higuchi K, Deguchi Y. Cocktail-Dosing Microdialysis Study to Simultaneously Assess Delivery of Multiple Organic–Cationic Drugs to the Brain. J Pharm Sci 2016; 105:935-940. [DOI: 10.1002/jps.24691] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 09/17/2015] [Accepted: 09/25/2015] [Indexed: 12/22/2022]
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18
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Memantine transport by a proton-coupled organic cation antiporter in hCMEC/D3 cells, an in vitro human blood-brain barrier model. Drug Metab Pharmacokinet 2015; 30:182-7. [DOI: 10.1016/j.dmpk.2014.12.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/11/2014] [Accepted: 12/21/2014] [Indexed: 11/23/2022]
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19
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Nagel J, Greco S, Parsons CG, Flik G, Tober C, Klein KU, Danysz W. Brain concentrations of mGluR5 negative allosteric modulator MTEP in relation to receptor occupancy--Comparison to MPEP. Pharmacol Rep 2015; 67:624-30. [PMID: 25933979 DOI: 10.1016/j.pharep.2015.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/02/2015] [Accepted: 01/02/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND To verify relation between brain free levels, receptor occupancy in vivo and in vitro affinity at the target for mGluR5 negative allosteric modulator (NAM) MTEP. METHODS We evaluated plasma and brain extra-cellular fluid (ECF) concentration of MTEP at behaviourally active dose (5mg/kg) using in vivo microdialysis. These values were compared it to the affinity in vitro (receptor binding and FLIPR) and to receptor occupancy in vivo. Another, related substance, MPEP was used for comparison. RESULTS MTEP and MPEP respectively inhibited mGluR5 receptors function in vitro with an affinity of 25.4 and 12.3 nM respectively. Accordingly peak ECF (extracellular fluid) levels were 1.3 and 0.14 μM, and peak total plasma levels were 7-11 and 2.6 μM. The ED50 for in vivo receptor occupancy was for both agents in the range of 0.8-0.7 mg/kg. CONCLUSIONS At behaviourally active dose MTEP produced complete mGluR5 receptor occupancy but over 50 times higher ECF concentrations than affinity for mGluR5 receptor in vitro. This difference is seems lower for other mGluR5 NAM compounds such as MPEP. A possibly explanation could be different distribution in body compartments of both agents leading to errors of estimation with the microdialysis technique or different pharmacological activity at the receptor.
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Affiliation(s)
- Jens Nagel
- Merz Pharmaceuticals GmbH, Frankfurt/Main, Germany
| | - Sergio Greco
- Merz Pharmaceuticals GmbH, Frankfurt/Main, Germany
| | | | - Gunnar Flik
- Brains On-Line B.V., Groningen, The Netherlands
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20
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Wild AR, Akyol E, Brothwell SLC, Kimkool P, Skepper JN, Gibb AJ, Jones S. Memantine block depends on agonist presentation at the NMDA receptor in substantia nigra pars compacta dopamine neurones. Neuropharmacology 2013; 73:138-46. [PMID: 23727219 DOI: 10.1016/j.neuropharm.2013.05.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 04/15/2013] [Accepted: 05/08/2013] [Indexed: 11/16/2022]
Abstract
NMDA glutamate receptors (NMDARs) have critical functional roles in the nervous system but NMDAR over-activity can contribute to neuronal damage. The open channel NMDAR blocker, memantine is used to treat certain neurodegenerative diseases, including Parkinson's disease (PD) and is well tolerated clinically. We have investigated memantine block of NMDARs in substantia nigra pars compacta (SNc) dopamine neurones, which show severe pathology in PD. Memantine (10 μM) caused robust inhibition of whole-cell (synaptic and extrasynaptic) NMDARs activated by NMDA at a high concentration or a long duration, low concentration. Less memantine block of NMDAR-EPSCs was seen in response to low frequency synaptic stimulation, while responses to high frequency synaptic stimulation were robustly inhibited by memantine; thus memantine inhibition of NMDAR-EPSCs showed frequency-dependence. By contrast, MK-801 (10 μM) inhibition of NMDAR-EPSCs was not significantly different at low versus high frequencies of synaptic stimulation. Using immunohistochemistry, confocal imaging and stereological analysis, NMDA was found to reduce the density of cells expressing tyrosine hydroxylase, a marker of viable dopamine neurones; memantine prevented the NMDA-evoked decrease. In conclusion, memantine blocked NMDAR populations in different subcellular locations in SNc dopamine neurones but the degree of block depended on the intensity of agonist presentation at the NMDAR. This profile may contribute to the beneficial effects of memantine in PD, as glutamatergic activity is reported to increase, and memantine could preferentially reduce over-activity while leaving some physiological signalling intact.
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Affiliation(s)
- A R Wild
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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21
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Nagakura A, Shitaka Y, Yarimizu J, Matsuoka N. Characterization of cognitive deficits in a transgenic mouse model of Alzheimer's disease and effects of donepezil and memantine. Eur J Pharmacol 2012; 703:53-61. [PMID: 23276665 DOI: 10.1016/j.ejphar.2012.12.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 12/07/2012] [Accepted: 12/18/2012] [Indexed: 11/18/2022]
Abstract
Alzheimer's disease is characterized by a progressive decline in cognitive function and involves β-amyloid (Aβ) in its pathogenesis. To characterize cognitive deficits associated with Aβ accumulation, we analyzed PS1/APP mice overexpressing mutant presenilin-1 (PS1, M146L; line 6.2) and amyloid precursor protein (APP, K670N/M671L; line Tg2576), a mouse model of Alzheimer's disease with accelerated Aβ production. Age-dependent changes in working and spatial memory behaviors were investigated using Y-maze and Morris water maze tasks, respectively, in female PS1/APP mice at ages of 2, 4, 6, and 12 months. Significant deficits in working and spatial memory were observed from 4 and 6 months of age, respectively. Acute single-dose administrations of memantine, a low-to-moderate-affinity N-methyl-d-aspartate (NMDA) antagonist, showed improvements in working memory deficits at 4 months of age, whereas donepezil, an acetylcholinesterase (AChE) inhibitor, did not. However, both drugs improved spatial memory dysfunction at 6 months of age at therapeutically relevant doses. No age-related dramatic changes were observed in expression levels of several proteins relating to memory dysfunction and also the mechanisms of donepezil and memantine in the cerebral cortex of PS1/APP mice until 6 months of age. Taken together, these results suggest dysfunctions in cholinergic and/or glutamatergic transmissions may be involved in the cognitive deficits associated with Aβ toxicity. Since donepezil and memantine have been widely used for treating patients of Alzheimer's disease, these results also suggest that cognitive deficits in PS1/APP mice assessed in the Y-maze and Morris water maze tasks are a useful animal model for evaluating novel Alzheimer's disease therapeutics.
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Affiliation(s)
- Akira Nagakura
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc., Tsukuba, Ibaraki 305-8585, Japan.
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Memantine inhibits α3β2-nAChRs-mediated nitrergic neurogenic vasodilation in porcine basilar arteries. PLoS One 2012; 7:e40326. [PMID: 22792283 PMCID: PMC3390354 DOI: 10.1371/journal.pone.0040326] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Accepted: 06/06/2012] [Indexed: 11/19/2022] Open
Abstract
Memantine, an NMDA receptor antagonist used for treatment of Alzheimer’s disease (AD), is known to block the nicotinic acetylcholine receptors (nAChRs) in the central nervous system (CNS). In the present study, we examined by wire myography if memantine inhibited α3β2-nAChRs located on cerebral perivascular sympathetic nerve terminals originating in the superior cervical ganglion (SCG), thus, leading to inhibition of nicotine-induced nitrergic neurogenic dilation of isolated porcine basilar arteries. Memantine concentration-dependently blocked nicotine-induced neurogenic dilation of endothelium-denuded basilar arteries without affecting that induced by transmural nerve stimulation, sodium nitroprusside, or isoproterenol. Furthermore, memantine significantly inhibited nicotine-elicited inward currents in Xenopous oocytes expressing α3β2-, α7- or α4β2-nAChR, and nicotine-induced calcium influx in cultured rat SCG neurons. These results suggest that memantine is a non-specific antagonist for nAChR. By directly inhibiting α3β2-nAChRs located on the sympathetic nerve terminals, memantine blocks nicotine-induced neurogenic vasodilation of the porcine basilar arteries. This effect of memantine is expected to reduce the blood supply to the brain stem and possibly other brain regions, thus, decreasing its clinical efficacy in the treatment of Alzheimer’s disease.
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Guadagna S, Bundgaard C, Hovelsø N, Volbracht C, Francis PT, Egebjerg J, Sotty F. Memantine potentiates hippocampal theta oscillations at a therapeutic dose in anesthetized mice: A mechanistic link to its cognitive-enhancing properties. Neuropharmacology 2012; 62:2208-18. [DOI: 10.1016/j.neuropharm.2012.01.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 12/21/2011] [Accepted: 01/18/2012] [Indexed: 01/10/2023]
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Wegener N, Nagel J, Gross R, Chambon C, Greco S, Pietraszek M, Gravius A, Danysz W. Evaluation of brain pharmacokinetics of (+)MK-801 in relation to behaviour. Neurosci Lett 2011; 503:68-72. [PMID: 21871531 DOI: 10.1016/j.neulet.2011.08.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 08/04/2011] [Accepted: 08/06/2011] [Indexed: 11/25/2022]
Abstract
The non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist (+)MK-801 is widely used in animal research (over 3000 publications), however its extracellular brain concentration has never been reported. Here, we show using in vivo microdialysis that systemic injection of (+)MK-801 at doses of 0.05, 0.1 or 0.2mg/kg resulted in peak brain ECF concentration of 6, 14 or 34 nM, respectively. Moreover, (+)MK-801 resulted in a dose-dependent learning impairment in the Morris water maze as well as hyperactivity in the open field. These data demonstrate for the first time that (+)MK-801 at doses producing behavioural alterations expected from NMDA receptor blockade reaches extracellular brain concentrations corresponding to the affinity at NMDA receptors.
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Affiliation(s)
- Nico Wegener
- Merz Pharmaceuticals GmbH, Dept. In vivo Pharmacology, Alfred-Wegener-Strasse 2, D-60438 Frankfurt am Main, Germany.
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Amantadine protects dopamine neurons by a dual action: reducing activation of microglia and inducing expression of GDNF in astroglia [corrected]. Neuropharmacology 2011; 61:574-82. [PMID: 21586298 DOI: 10.1016/j.neuropharm.2011.04.030] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 04/18/2011] [Accepted: 04/26/2011] [Indexed: 11/23/2022]
Abstract
Amantadine is commonly given to alleviate L-DOPA-induced dyskinesia of Parkinson's disease (PD) patients. Animal and human evidence showed that amantadine may also exert neuroprotection in several neurological disorders. Additionally, it is generally believed that this neuroprotection results from the ability of amantadine to inhibit glutamatergic NMDA receptor. However, several lines of evidence questioned the neuroprotective capacity of NMDA receptor antagonists in animal models of PD. Thus the cellular and molecular mechanism of neuroprotection of amantadine remains unclear. Using primary cultures with different composition of neurons, microglia, and astroglia we investigated the direct role of these glial cell types in the neuroprotective effect of amantadine. First, amantadine protected rat midbrain cultures from either MPP(+) or lipopolysaccharide (LPS), two toxins commonly used as PD models. Second, our studies revealed that amantadine reduced both LPS- and MPP(+)-induced toxicity of dopamine neurons through 1) the inhibition of the release of microglial pro-inflammatory factors, 2) an increase in expression of neurotrophic factors such as GDNF from astroglia. Lastly, differently from the general view on amantadine's action, we provided evidence suggesting that NMDA receptor inhibition was not crucial for the neuroprotective effect of amantadine. In conclusion, we report that amantadine protected dopamine neurons in two PD models through a novel dual mechanism, namely reducing the release of pro-inflammatory factors from activated microglia and increasing the expression of GNDF in astroglia.
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Lavergne F, Jay TM. A new strategy for antidepressant prescription. Front Neurosci 2010; 4:192. [PMID: 21151361 PMCID: PMC2995552 DOI: 10.3389/fnins.2010.00192] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 11/01/2010] [Indexed: 11/16/2022] Open
Abstract
From our research and literature search we propose an understanding of the mechanism of action of antidepressants treatments (ADTs) that should lead to increase efficacy and tolerance. We understand that ADTs promote synaptic plasticity and neurogenesis. This promotion is linked with stimulation of dopaminergic receptors. Previous evidence shows that all ADTs (chemical, electroconvulsive therapy, repetitive transcranial magnetic stimulation, sleep deprivation) increase at least one monoamine neurotransmitter serotonin (5-HT), noradrenaline (NA) or dopamine (DA); this article focuses on DA release or turn-over in the frontal cortex. DA increased dopaminergic activation promotes synaptic plasticity with an inverted U shape dose–response curve. Specific interaction between DA and glutamate is mediated by D1 receptor subtypes and Glutamate (NMDA) receptors with neurotrophic factors likely to play a modulatory role. With the understanding that all ADTs have a common, final, DA-ergic stimulation that promotes synaptic plasticity we can predict that (1) AD efficiency is related to the compound strength for inducing DA-ergic stimulation. (2) ADT efficiency presents a therapeutic window that coincides with the inverted U shape DA response curve. (3) ADT delay of action is related to a “synaptogenesis and neurogenesis delay of action.” (4) The minimum efficient dose can be found by starting at a low dosage and increasing up to the patient response. (5) An increased tolerance requires a concomitant prescription of a few ADTs, with different or opposite adverse effects, at a very low dose. (6) ADTs could improve all diseases with cognitive impairments and synaptic depression by increasing synaptic plasticity and neurogenesis.
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Affiliation(s)
- Francis Lavergne
- Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, INSERM U894, Centre Hospitalier Sainte-Anne Paris, France
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Motawaj M, Burban A, Davenas E, Arrang JM. Activation of Brain Histaminergic Neurotransmission: A Mechanism for Cognitive Effects of Memantine in Alzheimer's Disease. J Pharmacol Exp Ther 2010; 336:479-87. [DOI: 10.1124/jpet.110.174458] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Memantine preferentially blocks extrasynaptic over synaptic NMDA receptor currents in hippocampal autapses. J Neurosci 2010; 30:11246-50. [PMID: 20720132 DOI: 10.1523/jneurosci.2488-10.2010] [Citation(s) in RCA: 278] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the brain. The NMDA subtype of glutamate receptors (NMDAR) is known to mediate many physiological neural functions. However, excessive activation of NMDARs contributes to neuronal damage in various acute and chronic neurological disorders. To avoid unwanted adverse side effects, blockade of excessive NMDAR activity must therefore be achieved without affecting its physiological function. Memantine, an adamantane derivative, has been used for the treatment of Alzheimer's disease with an excellent clinical safety profile. We previously showed that memantine preferentially blocked neurotoxicity mediated by excessive NMDAR activity while relatively sparing normal neurotransmission, in part because of its uncompetitive antagonism with a fast off-rate. Here, using rat autaptic hippocampal microcultures, we show that memantine at therapeutic concentrations (1-10 microM) preferentially blocks extrasynaptic rather than synaptic currents mediated by NMDARs in the same neuron. We found that memantine blocks extrasynaptic NMDAR-mediated currents induced by bath application of 100 microM NMDA/10 microM glycine with a twofold higher potency than its blockade of the NMDAR component of evoked EPSCs (EPSCs(NMDAR)); this effect persists under conditions of pathological depolarization in the presence of 1 mm extracellular Mg(2+). Thus, our findings provide the first unequivocal evidence to explain the tolerability of memantine based on differential extrasynaptic/synaptic receptor blockade. At therapeutic concentrations, memantine effectively blocks excessive extrasynaptic NMDAR-mediated currents, while relatively sparing normal synaptic activity.
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Rammes G, Danysz W, Parsons CG. Pharmacodynamics of memantine: an update. Curr Neuropharmacol 2010; 6:55-78. [PMID: 19305788 PMCID: PMC2645549 DOI: 10.2174/157015908783769671] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 05/10/2007] [Accepted: 11/05/2007] [Indexed: 01/12/2023] Open
Abstract
Memantine received marketing authorization from the European Agency for the Evaluation of Medicinal Products (EMEA) for the treatment of moderately severe to severe Alzheimer s disease (AD) in Europe on 17(th) May 2002 and shortly thereafter was also approved by the FDA for use in the same indication in the USA. Memantine is a moderate affinity, uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist with strong voltage-dependency and fast kinetics. Due to this mechanism of action (MOA), there is a wealth of other possible therapeutic indications for memantine and numerous preclinical data in animal models support this assumption. This review is intended to provide an update on preclinical studies on the pharmacodynamics of memantine, with an additional focus on animal models of diseases aside from the approved indication. For most studies prior to 1999, the reader is referred to a previous review [196].In general, since 1999, considerable additional preclinical evidence has accumulated supporting the use of memantine in AD (both symptomatic and neuroprotective). In addition, there has been further confirmation of the MOA of memantine as an uncompetitive NMDA receptor antagonist and essentially no data contradicting our understanding of the benign side effect profile of memantine.
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Affiliation(s)
- G Rammes
- Clinical Neuropharmacology, Max Planck Institute of Psychiatry, 80804 Munich, Germany
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30
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Balance between synaptic versus extrasynaptic NMDA receptor activity influences inclusions and neurotoxicity of mutant huntingtin. Nat Med 2009; 15:1407-13. [PMID: 19915593 PMCID: PMC2789858 DOI: 10.1038/nm.2056] [Citation(s) in RCA: 320] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 10/02/2009] [Indexed: 02/07/2023]
Abstract
The neurodegenerative disorder Huntington disease (HD) is caused by an expanded CAG repeat in the huntingtin gene, resulting in loss of striatal and cortical neurons. Although, the gene product is widely expressed, it remains unclear why neurons are selectively targeted. Here, we demonstrate the relationship between synaptic and extrasynaptic activity, inclusion formation of mutant huntingtin protein (mtHtt), and neuronal survival. Synaptic NMDA receptor (NMDAR) activity induces mtHtt inclusions via a TCP1 ring complex (TRiC)-dependent mechanism, rendering neurons more resistant to mtHtt-mediated cell death. In contrast, stimulation of extrasynaptic NMDARs increases vulnerability of mtHtt-neurons to cell death by impairing a neuroprotective CREB—PGC-1α cascade and increasing the small guanine nucleotide-binding protein Rhes, which is known to sumoylate and disaggregate mtHtt. Treatment of transgenic YAC128 HD mice with low-dose memantine blocks extrasynaptic (but not synaptic) NMDARs and ameliorates neuropathological and behavioral manifestations. By contrast, high-dose memantine also blocks synaptic NMDAR activity, decreases neuronal inclusions, and worsens these outcomes. Our findings offer a rational therapeutic approach for protecting susceptible neurons in HD.
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31
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Liu C, Lin N, Wu B, Qiu Y. Neuroprotective effect of memantine combined with topiramate in hypoxic-ischemic brain injury. Brain Res 2009; 1282:173-82. [PMID: 19501064 DOI: 10.1016/j.brainres.2009.05.071] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2009] [Revised: 05/19/2009] [Accepted: 05/20/2009] [Indexed: 02/05/2023]
Abstract
Glutamate receptor-mediated neurotoxicity is a major mechanism contributing to hypoxic-ischemic brain injury (HIBI). Memantine is a safe non-competitive NMDA receptor blocker characterized by its low affinity and fast unblocking kinetics. Topiramate is an AMPA/KA receptor blocker and use-dependent sodium channel blocker with several other neuroprotective actions and little neurotoxicity. We hypothesized that the coadministration of memantine and topiramate would be highly effective to attenuate HIBI in neonatal rats. Seven-day-old Sprague-Dawley rat pups were subjected to right common carotid artery ligation and hypoxia for 2 h, and then were randomly and blindly assigned to one of four groups: vehicle, memantine, topiramate and combination group. Brain injury was evaluated by gross damage and weight deficit of the right hemisphere at 22d after hypoxic-ischemia (HI) and by neurofunctional assessment (foot-fault test) at 21d post-HI. Acute neuronal injury was also evaluated by microscopic damage grading at 72 h post-HI. Results showed the combination of memantine and topiramate improved both pathological outcome and performance significantly. The drug-induced apoptotic neurodegeneration was assessed by TUNEL staining at 48 h post-HI and the result showed no elevated apoptosis in all observed areas. The result of the experiment indicates the combination therapy is safe and highly effective to reduce brain damage after HIBI.
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Affiliation(s)
- Chunhua Liu
- Department of Pediatrics, The First Affiliated Hospital of Shantou University Medical College, 515000, Shantou, China
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32
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Lorrio S, Negredo P, Roda JM, García AG, López MG. Effects of memantine and galantamine given separately or in association, on memory and hippocampal neuronal loss after transient global cerebral ischemia in gerbils. Brain Res 2009; 1254:128-37. [DOI: 10.1016/j.brainres.2008.11.095] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 11/24/2008] [Accepted: 11/26/2008] [Indexed: 11/29/2022]
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Therapeutically relevant plasma concentrations of memantine produce significant L-N-methyl-D-aspartate receptor occupation and do not impair learning in rats. Behav Pharmacol 2008; 19:724-34. [DOI: 10.1097/fbp.0b013e3283123cad] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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34
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NMDA receptor blockade with memantine attenuates white matter injury in a rat model of periventricular leukomalacia. J Neurosci 2008; 28:6670-8. [PMID: 18579741 DOI: 10.1523/jneurosci.1702-08.2008] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hypoxia-ischemia (H/I) in the premature infant leads to white matter injury termed periventricular leukomalacia (PVL), the leading cause of subsequent neurological deficits. Glutamatergic excitotoxicity in white matter oligodendrocytes (OLs) mediated by cell surface glutamate receptors (GluRs) of the AMPA subtype has been demonstrated as one factor in this injury. Recently, it has been shown that rodent OLs also express functional NMDA GluRs (NMDARs), and overactivation of these receptors can mediate excitotoxic OL injury. Here we show that preterm human developing OLs express NMDARs during the PVL period of susceptibility, presenting a potential therapeutic target. The expression pattern mirrors that seen in the immature rat. Furthermore, the uncompetitive NMDAR antagonist memantine attenuates NMDA-evoked currents in developing OLs in situ in cerebral white matter of immature rats. Using an H/I rat model of white matter injury, we show in vivo that post-H/I treatment with memantine attenuates acute loss of the developing OL cell surface marker O1 and the mature OL marker MBP (myelin basic protein), and also prevents the long-term reduction in cerebral mantle thickness seen at postnatal day 21 in this model. These protective doses of memantine do not affect normal myelination or cortical growth. Together, these data suggest that NMDAR blockade with memantine may provide an effective pharmacological prevention of PVL in the premature infant.
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Memantine does not show intracellular block of the NMDA receptor channel. Eur J Pharmacol 2008; 587:99-103. [PMID: 18456253 DOI: 10.1016/j.ejphar.2008.03.053] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2007] [Revised: 02/27/2008] [Accepted: 03/10/2008] [Indexed: 11/23/2022]
Abstract
Mg2+ is known to gain access to the NMDA receptor channel from both the extra- and intracellular compartments. Memantine, being an amphiphilic substance, reaches intracellular concentrations of approximately 30 microM, which are much higher than therapeutic extracellular concentrations ( approximately 1 microM). We therefore investigated whether memantine can also block the NMDA receptor channel from the intracellular compartment. NR1a/NR2A receptors were expressed in Xenopus oocytes and in classical two electrode voltage-clamp recordings, voltage-ramps from -100 to +100 mV confirmed moderate inward rectification of NR1a/NR2A receptor control responses at positive membrane potentials above +40 mV. Patch clamp recordings from these same cells (applying 100 microM glutamate and 1 mM Mg2+) revealed similar rectification at positive potentials in cell-attached mode which disappeared after pulling an inside-out patch. Application of 1 mM Mg2+ to the intracellular side of the receptor re-introduced the rectification seen in cell-attached mode, and 5 mM Mg2+ produced much more pronounced block. In contrast, 30 microM memantine was completely unable to block the NMDA receptor from the intracellular compartment. In conclusion, intracellular block of the NMDA receptor, as reported for Mg2+, is not of significance for the therapeutic effects of memantine.
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36
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Hao J, Mdzinarishvili A, Abbruscato TJ, Klein J, Geldenhuys WJ, Van der Schyf CJ, Bickel U. Neuroprotection in mice by NGP1-01 after transient focal brain ischemia. Brain Res 2008; 1196:113-20. [PMID: 18234166 DOI: 10.1016/j.brainres.2007.11.075] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 11/29/2007] [Accepted: 11/29/2007] [Indexed: 10/22/2022]
Abstract
The effect of the polycyclic cage amine NGP1-01, a dual action antagonist at both L-type calcium channels and NMDA receptors, was measured after transient (1 h) focal cerebral ischemia in the mouse middle cerebral artery occlusion (MCAO) model. Mice were left untreated, or received NGP1-01 (20 mg/kg per dose intraperitoneally), memantine (20 mg/kg per dose intraperitoneally), or vehicle (DMSO) at 15 min, 24 h and 48 h after reperfusion. Sensorimotor function was tested daily for two weeks using the "corner test", a proven paradigm for the assessment of functional integrity in rodents. NGP1-01 significantly reduced sensorimotor deficits over the 2-week period (p<0.001, ANOVA). Although memantine was less effective than NGP1-01 (p<0.05), it still significantly attenuated sensorimotor deficits in the animals. In a separate study, brain damage 3 days after stroke was determined histologically in mice receiving no treatment, DMSO, or NGP1-01 (dosages and dosage schedule same as above). Serial brain sections were stained for nonviable neurons with Fluoro-Jade B and the volume of damaged tissue was estimated. NGP1-01 treated mice had a significantly lower volume of brain damage (13+/-7 mm(3), p<0.01) than both control groups (no treatment: 47+/-4 mm(3), DMSO: 50+/-10 mm(3)). In conclusion, at weight-equivalent doses, NGP1-01 was at least as neuroprotective as the established NMDA receptor antagonist memantine. It may be a promising lead structure for the development of novel multiple-action drugs in treating ischemic stroke and other neurodegenerative diseases with an excitotoxic component.
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Affiliation(s)
- Jiukuan Hao
- Department of Pharmaceutical Sciences and PATOS Stroke Research Center, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA
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37
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Werling LL, Keller A, Frank JG, Nuwayhid SJ. A comparison of the binding profiles of dextromethorphan, memantine, fluoxetine and amitriptyline: Treatment of involuntary emotional expression disorder. Exp Neurol 2007; 207:248-57. [PMID: 17689532 DOI: 10.1016/j.expneurol.2007.06.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 06/15/2007] [Accepted: 06/20/2007] [Indexed: 10/23/2022]
Abstract
We compared the binding profiles of medications potentially useful in the treatment of involuntary emotional expression disorder at twenty-six binding sites in rat brain tissue membranes. Sites were chosen based on likelihood of being target sites for the mechanism of action of the agents in treating the disorder or their likelihood in producing side effects experienced by patients treated with psychoactive agents. We used radioligand binding assays employing the most selective labeled ligands available for sites of interest. Concentrations of labeled ligand were used at or below the K(i) value of the ligand for the target site. Compounds were initially screened at 1 muM. For compounds that competed for greater than 20-30% of specific binding at target sites of interest, full concentration curves were constructed. Dextromethorphan, amitriptyline and fluoxetine competed for binding to sigma(1) receptors and to serotonin transporters with high to moderate affinity. Of the target sites tested, these are the most likely to contribute to the therapeutic benefit of the various agents. In addition, all three drugs showed some activity at alpha(2) and 5-HT(1B/D) sites. Of the drugs tested, dextromethorphan bound to the fewest sites unlikely to be target sites. Although the mechanism of action of dextromethorphan or any drug that has been used in the treatment of involuntary emotional expression disorder is currently unknown, our data support that the affinity of the drug for sigma(1) receptors is consistent with its possible action through this receptor type in controlling symptoms of the disorder.
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Affiliation(s)
- Linda L Werling
- Department of Pharmacology and Physiology, The George Washington University Medical Center, Washington, DC 20037, USA.
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38
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Lanckmans K, Stragier B, Sarre S, Smolders I, Michotte Y. Nano-LC-MS/MS for the monitoring of angiotensin IV in rat brain microdialysates: Limitations and possibilities. J Sep Sci 2007; 30:2217-24. [PMID: 17688302 DOI: 10.1002/jssc.200700159] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To broaden our knowledge about the central role of the angiotensin IV (Ang IV) peptide, we aimed to monitor its extracellular concentration in the brain using in vivo microdialysis. Ang IV was measured in the dialysates using a previously developed nano-LC-MS/MS assay with an LOD of 50 pM. Using this assay, baseline levels of Ang IV in dialysates from different brain structures were undetectable. However, immediately after microdialysis probe insertion, Ang IV could be detected in a concentration that varied between 120 and 187 pM. Using the zero-net-flux method, the extracellular levels of Ang IV in the striatum were estimated at 46 pM. These data may indicate that Ang IV is mainly present intracellularly. In addition, Ang IV was clearly measurable after striatal perfusion of Ang II. On the other hand, our nano-LC-MS/MS method was successful for the detection of Met-enkephalin and neurotensin in dialysates from the rat. In conclusion, the nano-LC-MS/MS method coupled with microdialysis is well suited to monitor the biologically significant conversion between Ang II and Ang IV in vivo, but physiological extracellular levels of Ang IV appear too low to be detected.
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Affiliation(s)
- Katrien Lanckmans
- Research Group Experimental Pharmacology, Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Vrije Universiteit Brussel, Brussels, Belgium
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Parsons CG, Stöffler A, Danysz W. Memantine: a NMDA receptor antagonist that improves memory by restoration of homeostasis in the glutamatergic system--too little activation is bad, too much is even worse. Neuropharmacology 2007; 53:699-723. [PMID: 17904591 DOI: 10.1016/j.neuropharm.2007.07.013] [Citation(s) in RCA: 464] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 06/19/2007] [Accepted: 07/17/2007] [Indexed: 12/13/2022]
Abstract
The neurotransmitter glutamate activates several classes of metabotropic receptor and three major types of ionotropic receptor--alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate and N-methyl-D-aspartate (NMDA). The involvement of glutamate mediated neurotoxicity in the pathogenesis of Alzheimer's disease (AD) is finding increasing scientific acceptance. Central to this hypothesis is the assumption that glutamate receptors, in particular of the NMDA type, are overactivated in a tonic rather than a phasic manner. Such continuous, mild, chronic activation ultimately leads to neuronal damage/death. Additionally, impairment of synaptic plasticity (learning) may result not only from neuronal damage per se but may also be a direct consequence of this continuous, non-contingent NMDA receptor activation. Complete NMDA receptor blockade has also been shown to impair neuronal plasticity, thus, both hypo- and hyperactivity of the glutamatergic system leads to dysfunction. Memantine received marketing authorization from the EMEA (European Medicines Agency) for the treatment of moderate to severe AD in Europe and was subsequently also approved by the FDA (Food and Drug Administration) for use in the same indication in the USA. Memantine is a moderate affinity, uncompetitive NMDA receptor antagonist with strong voltage-dependency and fast kinetics. This review summarizes existing hypotheses on the mechanism of action (MOA) of memantine in an attempt to understand how the accepted interaction with NMDA receptors could allow memantine to provide both neuroprotection and reverse deficits in learning/memory by the same MOA.
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Affiliation(s)
- Chris G Parsons
- Merz Pharmaceuticals, Eckenheimer Landstrasse 100, 60318 Frankfurt am Main, Germany
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40
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Giustizieri M, Cucchiaroni ML, Guatteo E, Bernardi G, Mercuri NB, Berretta N. Memantine inhibits ATP-dependent K+ conductances in dopamine neurons of the rat substantia nigra pars compacta. J Pharmacol Exp Ther 2007; 322:721-9. [PMID: 17496164 DOI: 10.1124/jpet.107.122036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
1-Amino-3,5-dimethyl-adamantane (memantine) is a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist used in clinical practice to treat neurodegenerative disorders that could be associated with excitotoxic cell death. Because memantine reduces the loss of dopamine neurons of the substantia nigra pars compacta (SNc) in animal models of Parkinson's disease, we examined the effects of this drug on dopamine cells of the SNc. Besides inhibition of NMDA receptor-mediated currents, memantine (30 and 100 microM) increased the spontaneous firing rate of whole-cell recorded dopamine neurons in a midbrain slice preparation. Occasionally, a bursting activity was observed. These effects were independent from the block of NMDA receptors and were prevented in neurons dialyzed with a high concentration of ATP (10 mM). An increase in firing rate was also induced by the ATP-sensitive potassium (K(ATP)) channel antagonist tolbutamide (300 microM), and this increase occluded further effects of memantine. In addition, K(ATP) channel-mediated outward currents, induced by hypoxia, were inhibited by memantine (30 and 100 microM) in the presence of the NMDA receptor antagonist (5S, 10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) (10 microM). An increase in the spontaneous firing rate by memantine was observed in dopamine neurons recorded with extracellular planar 8 x 8 multielectrodes in conditions of hypoglycemia. These results highlight K(ATP) channels as possible relevant targets of memantine effects in the brain. Moreover, in view of a proposed role of K(ATP) conductances in dopamine neuron degeneration, they suggest another mechanism of action underlying the protective role of memantine in Parkinson's disease.
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Wenk GL, Parsons CG, Danysz W. Potential role of N-methyl-D-aspartate receptors as executors of neurodegeneration resulting from diverse insults: focus on memantine. Behav Pharmacol 2007; 17:411-24. [PMID: 16940762 DOI: 10.1097/00008877-200609000-00007] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glutamatergic neurotransmission is critical to normal learning and memory and when the activity of glutamate neurons becomes excessive, or the normal function of its primary receptors becomes dysfunctional, this may lead to pathological changes associated with age-related neurodegenerative diseases. Anomalous glutamatergic activity associated with Alzheimer's disease may be due to a postsynaptic receptor and downstream defects that produce inappropriately timed or sustained glutamate activation of N-methyl-D-aspartate receptors, leading to neuronal injury and death and cognitive deficits associated with dementia. The mechanisms leading to the condition of chronically depolarized membranes on vulnerable neurons in the Alzheimer's disease brain are likely due to a complex interaction between oxidative stress, mitochondrial failure, chronic brain inflammation and the presence of amyloid-beta and hyperphosphorylated-tau; each of these factors are highly interrelated with each other and are discussed with an emphasis upon potential therapeutic mechanisms underlying the neuroprotective actions of memantine.
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Affiliation(s)
- Gary L Wenk
- Department Psychology & Neuroscience, Ohio State University, Ohio, USA
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Sinn DI, Lee ST, Chu K, Jung KH, Song EC, Kim JM, Park DK, Kim M, Roh JK. Combined neuroprotective effects of celecoxib and memantine in experimental intracerebral hemorrhage. Neurosci Lett 2007; 411:238-42. [PMID: 17123715 DOI: 10.1016/j.neulet.2006.10.050] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 10/13/2006] [Accepted: 10/13/2006] [Indexed: 11/18/2022]
Abstract
Memantine, a N-methyl-D-aspartate (NMDA) receptor antagonist, inhibits hematoma expansion and celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, reduces perihematomal inflammation in intracerebral hemorrhage. We examined whether the combination treatment has additive effects in experimental intracerebral hemorrhage (ICH). ICH was induced using stereotaxic infusion of collagenase into brains of adult rats. After the induction of ICH, rats were treated with intraperitoneal injection of memantine (20 mg/kg), celecoxib (20 mg/kg) or both agents. Only vehicles were administrated in rats of the control group. Results showed that the combination treatment of memantine and celecoxib reduced both hematoma volume and brain edema. Combination treatment also induced the better functional recovery with further attenuation of cerebral inflammation and apoptosis compared to the control group. When compared to the single agent groups, the combination treatment showed better effects in neuroprotection and anti-inflammation. These results suggest the feasible combined application of memantine and celecoxib in ICH treatment.
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Affiliation(s)
- Dong-In Sinn
- Stroke & Neural Stem Cell Laboratory in the Clinical Research Institute, Stem Cell Research Center, Department of Neurology, Seoul National University Hospital, Seoul, South Korea
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Abstract
Most neuroprotective drugs have failed in clinical trials because of side-effects, causing normal brain function to become compromised. A case in point concerns antagonists of the N-methyl-D-aspartate type of glutamate receptor (NMDAR). Glutamate receptors are essential to the normal function of the central nervous system. However, their excessive activation by excitatory amino acids, such as glutamate itself, is thought to contribute to neuronal damage in many neurological disorders ranging from acute hypoxic-ischemic brain injury to chronic neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. The dual role of NMDARs in particular for normal and abnormal functioning of the nervous system imposes important constraints on possible therapeutic strategies aimed at ameliorating neurological diseases. Blockade of excessive NMDAR activity must therefore be achieved without interference with its normal function. In general, NMDAR antagonists can be categorized pharmacologically according to the site of action on the receptor-channel complex. These include drugs acting at the agonist (NMDA) or co-agonist (glycine) sites, channel pore, and modulatory sites, such as the S-nitrosylation site where nitric oxide (NO) reacts with critical cysteine thiol groups. Because glutamate is thought to be the major excitatory transmitter in the brain, generalized inhibition of a glutamate receptor subtype like the NMDAR causes side-effects that clearly limit the potential for clinical applications. Both competitive NMDA and glycine antagonists, even although effective in preventing glutamate-mediated neurotoxicity, will cause generalized inhibition of NMDAR activities and thus have failed in many clinical trials. Open-channel block with the property of uncompetitive antagonism is the most appealing strategy for therapeutic intervention during excessive NMDAR activation as this action of blockade requires prior activation of the receptor. This property, in theory, leads to a higher degree of channel blockade in the presence of excessive levels of glutamate and little blockade at relatively lower levels, for example, during physiological neurotransmission. Utilizing this molecular strategy of action, we review here the logical process that we applied over the past decade to help develop memantine as the first clinically tolerated yet effective agent against NMDAR-mediated neurotoxicity. Phase 3 (final) clinical trials have shown that memantine is effective in treating moderate-to-severe Alzheimer's disease while being well tolerated. Memantine is also currently in trials for additional neurological disorders, including other forms of dementia, glaucoma, and severe neuropathic pain. Additionally, taking advantage of memantine's preferential binding to open channels and the fact that excessive NMDAR activity can be down-regulated by S-nitrosylation, we have recently developed combinatorial drugs called NitroMemantines. These drugs use memantine as a homing signal to target NO to hyperactivated NMDARs in order to avoid systemic side-effects of NO such as hypotension (low blood pressure). These second-generation memantine derivatives are designed as pathologically activated therapeutics, and in preliminary studies appear to have even greater neuroprotective properties than memantine.
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Affiliation(s)
- Huei-Sheng Vincent Chen
- Burnham Institute for Medical Research and the University of California-San Diego, La Jolla, California 92037, USA.
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McAdoo DJ, Hughes MG, Nie L, Shah B, Clifton C, Fullwood S, Hulsebosch CE. The effect of glutamate receptor blockers on glutamate release following spinal cord injury. Lack of evidence for an ongoing feedback cascade of damage --> glutamate release --> damage --> glutamate release --> etc. Brain Res 2005; 1038:92-9. [PMID: 15748877 DOI: 10.1016/j.brainres.2005.01.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2004] [Revised: 01/03/2005] [Accepted: 01/09/2005] [Indexed: 11/25/2022]
Abstract
It is widely hypothesized that excitotoxicity of released glutamate following a CNS insult is propagated by the cyclic cascade: glutamate release --> damage --> glutamate release --> further damage --> etc. We tested this hypothesis by determining the effects of attempting to interrupt the loop by administering glutamate receptor antagonists and Na(+)-channel blockers on glutamate release following spinal cord injury (SCI). The effects of administering the NMDA receptor blockers MK-801 and memantine, the AMPA/kainate receptor blockers NBQX and GYKI 52466, the AMPA receptor desensitization blocker cyclothiazide and the sodium channel blockers riluzole, mexiletine and QX-314 on post-SCI were determined. Agents were administered into the site of injury by direct injection, by microdialysis or systemically. None of these agents had an appreciable effect on glutamate release following SCI. Thus, it is unlikely that the above cascade produces significant secondary glutamate release and ongoing damage following SCI, although such cascades may worsen other CNS insults. We attribute our results to overwhelming effects of much greater release by direct mechanical damage and reversal of transport following SCI.
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Affiliation(s)
- David J McAdoo
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1043, USA.
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Strazielle N, Ghersi-Egea JF. Factors affecting delivery of antiviral drugs to the brain. Rev Med Virol 2005; 15:105-33. [PMID: 15546130 DOI: 10.1002/rmv.454] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Although the CNS is in part protected from peripheral insults by the blood-brain barrier and the blood-cerebrospinal fluid barrier, a number of human viruses gain access to the brain, replicate within this organ, or sustain latent infection. The efficacy of antiviral drugs towards the cerebral viral load is often limited as both blood-brain interfaces impede their cerebral distribution. For polar compounds, the major factor restricting their entry lies in the tight junctions that occlude the paracellular pathway across these barriers. For compounds with more favourable lipid solubility properties, CNS penetration will be function of a number of physicochemical factors that include the degree of lipophilicity, size and ability to bind to protein or red blood cells, as well as other factors inherent to the vascular and choroidal systems, such as the local cerebral blood flow and the surface area available for exchange. In addition, influx and efflux transport systems, or metabolic processes active in both capillary endothelial cells and choroid plexus epithelial cells, can greatly change the bioavailability of a drug in one or several compartments of the CNS. The relative importance of these various factors with respect to the CNS delivery of the different classes of antiviral drugs is illustrated and discussed.
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Sonkusare SK, Kaul CL, Ramarao P. Dementia of Alzheimer's disease and other neurodegenerative disorders--memantine, a new hope. Pharmacol Res 2005; 51:1-17. [PMID: 15519530 DOI: 10.1016/j.phrs.2004.05.005] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2004] [Indexed: 11/28/2022]
Abstract
Alzheimer's disease is the fourth largest cause of death for people over 65 years of age. Dementia of Alzheimer's type is the commonest form of dementia, the other two forms being vascular dementia and mixed dementia. At present, the therapy of Alzheimer's disease is aimed at improving both, cognitive and behavioural symptoms and thereby, quality of life for the patients. Since the discovery of Alzheimer's disease by Alois Alzheimer, many pathological mechanisms have been proposed which led to the testing of various new treatments. Until recently the available drugs for the treatment of Alzheimer's disease are cholinesterase inhibitors, which have limited success because these drugs improve cognitive functions only in mild dementia and cannot stop the process of neurodegeneration. Moreover, drugs of this category show gastrointestinal side effects. As the cells of central and peripheral nervous system cannot regenerate, newer strategies are aimed at preserving the surviving neurons by preventing their degeneration. NMDA-receptor-mediated glutamate excitotoxicity plays a major role in Abeta-induced neuronal death. Hence, it was thought that NMDA receptors could be a promising target for preventing the progression of Alzheimer's disease. All the compounds synthesized initially in this category showed toxicity mainly because of their high affinity for NMDA receptors. Memantine (1-amino adamantane derivative), NMDA-receptor antagonist was reported to be effective therapeutically in Alzheimer's disease. It was available in Germany as well as European Union and has been approved for moderate to severe dementia in United States of America recently. It is an uncompetitive, moderate affinity antagonist of NMDA receptors that inhibits the pathological functions of NMDA receptors while physiological processes in learning and memory are unaffected. Memantine is also reported to have beneficial effects in other CNS disorders viz., Parkinson's disease (PD), stroke, epilepsy, CNS trauma, amyotrophic lateral sclerosis (ALS), drug dependence and chronic pain. Mechanisms of neuroprotection, preclinical and clinical evidence for effectiveness of memantine have been provided. Pharmacology and pharmacokinetics of memantine and other NMDA-receptor antagonists in comparison with currently approved drugs for dementia treatment have been discussed. The focus is on 'glutamate excitotoxicity' and glutamate receptors as drug target. Various other novel strategies for the treatment of dementia of neurodegenerative disorders have also been discussed.
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Affiliation(s)
- S K Sonkusare
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Mohali 160 062, India
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Higashi Y, Uemori I, Fujii Y. Simultaneous determination of amantadine and rimantadine by HPLC in rat plasma with pre-column derivatization and fluorescence detection for pharmacokinetic studies. Biomed Chromatogr 2005; 19:655-62. [PMID: 15803448 DOI: 10.1002/bmc.492] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We investigated simultaneous high-performance liquid chromatographic (HPLC) determination of amantadine hydrochloride (AMA) and rimantadine hydrochloride (RIM) levels in rat plasma after fluorescent derivatization with o-phthalaldehyde and 2-mercaptoethanol. Afterwards, the method was applied to determine their pharmacokinetics. The retention times of AMA and RIM derivatives were 12.6 and 22.2 min and the lower limits of detection were 0.025 and 0.016 microg/mL, respectively. The coefficients of variation for intra- and inter-day assay of AMA and RIM were less than 5.1 and 7.6%, respectively. After i.v. administration of AMA or RIM to rats, the total body clearance and distribution volume at the steady-state of RIM were higher than those of AMA. Bioavailability of AMA and RIM was 34.9 and 37.2%, respectively. When AMA and RIM were p.o. co-administered, the area under the plasma concentration--time curve of RIM was significantly lower than that after RIM alone. On the other hand, pharmacokinetic parameters of AMA did not significantly change. These results indicate that our HPLC assay is simple, rapid, sensitive and reproducible for simultaneously determining AMA and RIM concentrations in rat plasma and is applicable to their pharmacokinetic studies. Also, co-administration of AMA and RIM may result in the lack of pharmacological effects of RIM.
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Affiliation(s)
- Yasuhiko Higashi
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3, Kanagawa-machi, Kanazawa 920-1181, Japan.
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Higashi Y, Fujii Y. Liquid chromatographic determination of 1-adamantanamine and 2-adamantanamine in human plasma after pre-column derivatization with o-phthalaldehyde and 1-thio-β-d-glucose. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 799:349-54. [PMID: 14670755 DOI: 10.1016/j.jchromb.2003.10.062] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We investigated high-performance liquid chromatographic (HPLC) determination of 1-adamantanamine hydrochloride (1-ADA) and 2-adamantanamine hydrochloride (2-ADA) in human plasma after the derivatization with o-phthalaldehyde (OPA) and 1-thio-beta-D-glucose (TG). Extracted human plasma samples were mixed with OPA and TG at room temperature for 6 min and injected onto HPLC. Retention times of 1-ADA and 2-ADA derivatives were 12.6 and 14.1 min, respectively. The lower limits of detection of 1-ADA and 2-ADA were 0.02 and 0.008 microg/ml, and the lower limits of quantitation of 1-ADA and 2-ADA were 0.025 and 0.01 microg/ml, respectively. The coefficients of variation for intra-day and inter-day assay of 1-ADA and 2-ADA were less than 4.4 and 6.0%, respectively. L-Dopa and dopamine were not found to interfere with the peaks of 1-ADA and 2-ADA derivatives. Human plasma unbound fraction (f(p)) values of 1-ADA varied between 0.32 and 0.48, while those of 2-ADA varied between 0.38 and 0.68. These results indicate that HPLC assay of 1-ADA and 2-ADA by derivatization with OPA and TG is simple, rapid, sensitive and reproducible for determining 1-ADA and 2-ADA in human plasma.
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Affiliation(s)
- Yasuhiko Higashi
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3, Kanagawa-machi, Kanazawa 920-1181, Japan.
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Rogawski MA, Wenk GL. The neuropharmacological basis for the use of memantine in the treatment of Alzheimer's disease. CNS DRUG REVIEWS 2003; 9:275-308. [PMID: 14530799 PMCID: PMC6741669 DOI: 10.1111/j.1527-3458.2003.tb00254.x] [Citation(s) in RCA: 266] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Memantine has been demonstrated to be safe and effective in the symptomatic treatment of Alzheimer's disease (AD). While the neurobiological basis for the therapeutic activity of memantine is not fully understood, the drug is not a cholinesterase inhibitor and, therefore, acts differently from current AD therapies. Memantine can interact with a variety of ligand-gated ion channels. However, NMDA receptors appear to be a key target of memantine at therapeutic concentrations. Memantine is an uncompetitive (channel blocking) NMDA receptor antagonist. Like other NMDA receptor antagonists, memantine at high concentrations can inhibit mechanisms of synaptic plasticity that are believed to underlie learning and memory. However, at lower, clinically relevant concentrations memantine can under some circumstances promote synaptic plasticity and preserve or enhance memory in animal models of AD. In addition, memantine can protect against the excitotoxic destruction of cholinergic neurons. Blockade of NMDA receptors by memantine could theoretically confer disease-modifying activity in AD by inhibiting the "weak" NMDA receptor-dependent excitotoxicity that has been hypothesized to play a role in the progressive neuronal loss that underlies the evolving dementia. Moreover, recent in vitro studies suggest that memantine abrogates beta-amyloid (Abeta) toxicity and possibly inhibits Abeta production. Considerable attention has focused on the investigation of theories to explain the better tolerability of memantine over other NMDA receptor antagonists, particularly those that act by a similar channel blocking mechanism such as dissociative anesthetic-like agents (phencyclidine, ketamine, MK-801). A variety of channel-level factors could be relevant, including fast channel-blocking kinetics and strong voltage-dependence (allowing rapid relief of block during synaptic activity), as well as reduced trapping (permitting egress from closed channels). These factors may allow memantine to block channel activity induced by low, tonic levels of glutamate--an action that might contribute to symptomatic improvement and could theoretically protect against weak excitotoxicity--while sparing synaptic responses required for normal behavioral functioning, cognition and memory.
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Affiliation(s)
- Michael A Rogawski
- Epilepsy Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-4457, USA.
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Rao VL, Dogan A, Todd KG, Bowen KK, Dempsey RJ. Neuroprotection by memantine, a non-competitive NMDA receptor antagonist after traumatic brain injury in rats. Brain Res 2001; 911:96-100. [PMID: 11489449 DOI: 10.1016/s0006-8993(01)02617-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated whether memantine, a non-competitive NMDA receptor antagonist is neuroprotective after traumatic brain injury (TBI) induced in adult rats with a controlled cortical impact device. TBI led to significant neuronal death in the hippocampal CA2 and CA3 regions (by 50 and 59%, respectively), by 7 days after the injury. Treatment of rats with memantine (10 and 20 mg/Kg, i.p.) immediately after the injury significantly prevented the neuronal loss in both CA2 and CA3 regions. This is the first study showing the neuroprotective potential of memantine to prevent the TBI-induced neuronal damage.
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Affiliation(s)
- V L Rao
- Department of Neurological Surgery, University of Wisconsin-Madison, H4/336 CSC, 600 Highland Avenue, Madison, WI 53792, USA
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