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Ragot A, Luhmann HJ, Dipper-Wawra M, Heinemann U, Holtkamp M, Fidzinski P. Pathology-selective antiepileptic effects in the focal freeze-lesion rat model of malformation of cortical development. Exp Neurol 2021; 343:113776. [PMID: 34058228 DOI: 10.1016/j.expneurol.2021.113776] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 05/13/2021] [Accepted: 05/27/2021] [Indexed: 01/29/2023]
Abstract
Malformations of cortical development (MCD) represent a group of rare diseases with severe clinical presentation as epileptic and pharmacoresistant encephalopathies. Morphological studies in tissue from MCD patients have revealed reduced GABAergic efficacy and increased intracellular chloride concentration in neuronal cells as important pathophysiological mechanisms in MCD. Also, in various animal models, alterations of GABAergic inhibition have been postulated as a predominant factor contributing to perilesional hyperexcitability. Along with this line, the NKCC1 inhibitor bumetanide has been postulated as a potential drug for treatment of epilepsy, mediating its antiepileptic effect by reduction of the intracellular chloride and increased inhibitory efficacy of GABAergic transmission. In the present study, we focused on the focal freeze-lesion model of MCD to compare antiepileptic drugs with distinct mechanisms of action, including NKCC1 inhibition by bumetanide. For this purpose, we combined electrophysiological and optical methods in slice preparations and assessed the properties of seizure like events (SLE) induced by 4-aminopyridine. In freeze-lesioned but not control slices, SLE onset was confined to the perilesional area, confirming that this region is hyperexcitable and likely triggers pathological activity. Bumetanide selectively reduced epileptic activity in lesion-containing slices but not in slices from sham-treated control rats. Moreover, bumetanide caused a shift in the SLE onset site away from the perilesional area. In contrast, effects of other antiepileptic drugs including carbamazepine, lacosamide, acezatolamide and zonisamide occurred mostly independently of the lesion and did not result in a shift of the onset region. Our work adds evidence for the functional relevance of chloride homeostasis in the pathophysiology of microgyrus formation as represented in the focal freeze-lesion model. Further studies in different MCD models and human tissue will be required to validate the effects across different MCD subtypes and species and to assess the translational value of our findings.
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Affiliation(s)
- Aliénor Ragot
- Charité - Universitätsmedizin Berlin, Clinical and Experimental Epileptology, Department of Neurology, Charitéplatz 1, 10117 Berlin, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Matthias Dipper-Wawra
- Charité - Universitätsmedizin Berlin, Clinical and Experimental Epileptology, Department of Neurology, Charitéplatz 1, 10117 Berlin, Germany
| | - Uwe Heinemann
- Charité - Universitätsmedizin Berlin, Institute of Neurophysiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Martin Holtkamp
- Charité - Universitätsmedizin Berlin, Clinical and Experimental Epileptology, Department of Neurology, Charitéplatz 1, 10117 Berlin, Germany; Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany
| | - Pawel Fidzinski
- Charité - Universitätsmedizin Berlin, Clinical and Experimental Epileptology, Department of Neurology, Charitéplatz 1, 10117 Berlin, Germany; Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany; Berlin Institute of Health at Charité -Universitätsmedizin Berlin, NeuroCure Clinical Research Center, Charitéplatz 1, 10117 Berlin, Germany.
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Heuzeroth H, Wawra M, Fidzinski P, Dag R, Holtkamp M. The 4-Aminopyridine Model of Acute Seizures in vitro Elucidates Efficacy of New Antiepileptic Drugs. Front Neurosci 2019; 13:677. [PMID: 31316344 PMCID: PMC6610309 DOI: 10.3389/fnins.2019.00677] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 06/13/2019] [Indexed: 12/28/2022] Open
Abstract
Up to date, preclinical screening for new antiepileptic substances is performed by a combination of different in vivo models of acute seizures, for which large numbers of animals are necessary. So far, little attention has been paid to in vitro models, which are also able to detect antiepileptic efficacy and in principle could likewise serve for exploratory preclinical screening. One of the established in vitro models of acute seizures is the 4-aminopyridine (4-AP) model. Previous studies have shown that the 4-AP model is capable to recapitulate the antiepileptic efficacy of standard antiepileptic drugs (AEDs) such as valproate or carbamazepine. Here, we employed a dual methodological approach using electrophysiology and optical imaging to systematically test the antiepileptic efficacy of three new-generation AEDs with distinct mechanisms of action (lacosamide, zonisamide, and levetiracetam). We found that frequency of 4-AP induced seizure like events (SLE) was the most sensitive parameter to detect dose-dependent antiepileptic effects in these compounds. Specifically, levetiracetam reduced SLE frequency while lacosamide and zonisamide at higher doses completely blocked SLE incidence. Analysis of the intrinsic optical signal additionally revealed a subiculum-specific reduction of the area involved in the propagation of ictal activity when lacosamide or zonisamide were administered. Taken together, our data adds some evidence that acute seizure models in vitro are in principle capable to detect antiepileptic effects across different mechanisms of action with efficacy similar to acute models in vivo. Further studies with negative controls, e.g., penicillin as a proconvulsant, and other clinically relevant AEDs are needed to determine if this acute in vitro model might be useful as exploratory screening tool. In view of the increasing sensitivity toward animal welfare, an affective in vitro model may help to reduce the number of laboratory animals deployed in burdening in vivo experiments and to preselect substances for subsequent testing in time- and cost-laborious models of chronic epilepsy.
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Affiliation(s)
- Hanno Heuzeroth
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Matthias Wawra
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Pawel Fidzinski
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ramazan Dag
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Martin Holtkamp
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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Ruangkittisakul A, Sharopov S, Kantor C, Kuribayashi J, Mildenberger E, Luhmann H, Kilb W, Ballanyi K. Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks. Neuroscience 2015; 301:106-20. [DOI: 10.1016/j.neuroscience.2015.05.069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/11/2015] [Accepted: 05/27/2015] [Indexed: 11/29/2022]
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Schulze-Bonhage A. The safety and long-term efficacy of zonisamide as adjunctive therapy for focal epilepsy. Expert Rev Neurother 2015; 15:857-65. [PMID: 26144543 DOI: 10.1586/14737175.2015.1065179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Epilepsy is a chronic disease which affects 1% of the population worldwide. As treatment is required for many years or decades, the long-term efficacy and tolerability of antiepileptic drugs are particularly important. Zonisamide (ZNS) is a second-generation antiepileptic drug with a unique structure and multiple mechanisms of action. Here, recently published long-term outcomes of patient cohorts with focal epilepsy undergoing ZNS treatment are discussed. Whereas ZNS monotherapy maintains similar seizure control efficacy to carbamazepine after 2 years of treatment, seizure-free rates are low in pharmacoresistant patients undergoing late adjunctive therapy. In preselected patient populations derived from double-blind studies, long-term seizure reduction and responder rates support sustained ZNS efficacy, good adherence and long-term retention. Adverse effects include somnolence and weight decrease, but data suggest that long-term treatment with ZNS is safe with only rare newly occurring adverse effects, and good long-term tolerability also regarding mood, behavior, cognition and bone maturation.
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Pietrzak B, Zwierzyńska E, Krupa A. A Pharmaco-EEG-Based Assessment of the Interaction Between Ethanol and Zonisamide. Alcohol Alcohol 2014; 49:505-14. [DOI: 10.1093/alcalc/agu024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
INTRODUCTION Carbonic anhydrase (CA) inhibitors have an impressive safety record despite the multiple functions that CA isozymes serve because they are not fully inhibited with most dosing. While reducing the targeted CA-dependent process sufficiently for disease control, residual activity and uncatalyzed rates in combination with compensations are adequate to avoid lethal consequences. Some drugs have in vitro selectivity differences against the 13 active isozymes, but none are convincingly selective in vivo or clinically. Efforts to synthesize selective inhibitors should result in safer drugs with fewer side effects. AREAS COVERED This review will focus on approved drugs with CA-inhibiting activity, whether used directly for this purpose or others. Side effects are discussed in relation to various organ systems and the disease being treated. Causes of side effects are considered, and strategies for symptom reduction are given. EXPERT OPINION Common side effects of paresthesias, dyspepsia, lassitude and fatigue in 30 - 40% of patients are generally tolerable or abate, but if not can be partially relieved by bicarbonate supplementation. The most important safety concerns are severe acidosis, respiratory failure and encephalopathy in patients with renal, pulmonary and hepatic disease where caution is critical, as is also the case in persons with sulfa drug allergies.
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Affiliation(s)
- Erik R Swenson
- University of Washington - Medical Service, VA Puget Sound Health Care System , 1660 S Columbian Way, S-111-PLUM, Seattle, WA 98108 , USA
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Porter RJ, Dhir A, Macdonald RL, Rogawski MA. Mechanisms of action of antiseizure drugs. HANDBOOK OF CLINICAL NEUROLOGY 2012; 108:663-681. [PMID: 22939059 DOI: 10.1016/b978-0-444-52899-5.00021-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Roger J Porter
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Antel J, Hebebrand J. Weight-reducing side effects of the antiepileptic agents topiramate and zonisamide. Handb Exp Pharmacol 2012:433-466. [PMID: 22249827 DOI: 10.1007/978-3-642-24716-3_20] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Drug-induced weight alteration can be a serious side effect that applies to several therapeutic agents and must be referred to in the respective approved labeling texts. The side effect may become health threatening in case of significant weight change in either direction. Several antiepileptic drugs (AEDs) are associated with weight gain such as gabapentin, pregabalin, valproic acid, and vigabatrin and to some extent carbamazepine. Others are weight neutral such as lamotrigine, levetiracetam, and phenytoin or associated with slight weight loss as, e.g., felbamate. The focus of this chapter is on the two AEDs causing strong weight loss: topiramate and zonisamide. For both drugs, several molecular mechanisms of actions are published. We provide a review of these potential mechanisms, some of which are based on in vivo studies in animal models for obesity, and of clinical studies exploring these two drugs as single entities or in combinations with other agents.
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Affiliation(s)
- J Antel
- Pharmaceutical Institute, University of Bonn, Lauenauerstrasse 63, 31848, Bad Münder, Germany.
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Costa C, Tozzi A, Luchetti E, Siliquini S, Belcastro V, Tantucci M, Picconi B, Ientile R, Calabresi P, Pisani F. Electrophysiological actions of zonisamide on striatal neurons: Selective neuroprotection against complex I mitochondrial dysfunction. Exp Neurol 2010; 221:217-24. [DOI: 10.1016/j.expneurol.2009.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/02/2009] [Accepted: 11/03/2009] [Indexed: 12/21/2022]
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Bonnet U, Bingmann D, Wiltfang J, Scherbaum N, Wiemann M. Modulatory effects of neuropsychopharmaca on intracellular pH of hippocampal neurones in vitro. Br J Pharmacol 2009; 159:474-83. [PMID: 20015293 DOI: 10.1111/j.1476-5381.2009.00540.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The intracellular pH (pHi) of neurones is tightly regulated by, for example, membrane-bound acid-exchangers and loaders. Nevertheless, excessive bioelectric activity lowers steady-state pHi. In turn, even a moderate acidification can inhibit neuronal activity, a process believed to be part of a negative feedback loop controlling neuronal excitation. As moclobemide, an antidepressant, and also some antiepileptic drugs can reduce neuronal pHi in hippocampus slices in vitro, we screened a panel of currently used neuropsychopharmaca for comparable effects. EXPERIMENTAL APPROACH BCECF-AM loaded hippocampal slices were superfused with 16 different neuroleptics, antidepressants and antiepileptics under bicarbonate-buffered conditions. Changes in steady-state pHi of CA3 neurones were measured fluorometrically. KEY RESULTS The antipsychotics haloperidol, clozapine, ziprasidone, and the antidepressants amitriptyline, doxepin, trimipramine, citalopram, mirtazapine, as well as the anticonvulsive drug tiagabine reversibly reduced the steady-state pHi by up to 0.35 pH-units in concentrations of 5-50 microM. In contrast, venlafaxine, the anticonvulsants carbamazepine, clonazepam, gabapentin, lamotrigine, zonisamide, and the mood stabilizer lithium had no effect on neuronal pHi. CONCLUSION AND IMPLICATIONS These data substantiate the view that clinically relevant concentrations of neuroleptics and antidepressants can mediate changes in neuronal pHi, which may contribute to their pharmacological mode of action. Effects on pHi should be taken into account when therapeutic or even harmful effects of these drugs are evaluated.
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Affiliation(s)
- Udo Bonnet
- Department of Psychiatry and Psychotherapy, LVR-Hospital of Essen, University of Duisburg/Essen, Essen, Germany.
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De Simone G, Scozzafava A, Supuran CT. Which Carbonic Anhydrases are Targeted by the Antiepileptic Sulfonamides and Sulfamates? Chem Biol Drug Des 2009; 74:317-21. [DOI: 10.1111/j.1747-0285.2009.00857.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Matar N, Jin W, Wrubel H, Hescheler J, Schneider T, Weiergräber M. Zonisamide block of cloned human T-type voltage-gated calcium channels. Epilepsy Res 2009; 83:224-34. [DOI: 10.1016/j.eplepsyres.2008.11.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 11/07/2008] [Accepted: 11/11/2008] [Indexed: 01/01/2023]
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Supuran C. Antiepileptic activity of zonisamide on hippocampal CA3 neurons does not depend on carbonic anhydrase inhibition. Epilepsy Res 2008; 82:109; author reply 110. [DOI: 10.1016/j.eplepsyres.2008.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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