1
|
Koch NA, Sonnenberg L, Hedrich UBS, Lauxmann S, Benda J. Loss or gain of function? Effects of ion channel mutations on neuronal firing depend on the neuron type. Front Neurol 2023; 14:1194811. [PMID: 37292138 PMCID: PMC10244640 DOI: 10.3389/fneur.2023.1194811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/03/2023] [Indexed: 06/10/2023] Open
Abstract
Introduction Clinically relevant mutations to voltage-gated ion channels, called channelopathies, alter ion channel function, properties of ionic currents, and neuronal firing. The effects of ion channel mutations are routinely assessed and characterized as loss of function (LOF) or gain of function (GOF) at the level of ionic currents. However, emerging personalized medicine approaches based on LOF/GOF characterization have limited therapeutic success. Potential reasons are among others that the translation from this binary characterization to neuronal firing is currently not well-understood-especially when considering different neuronal cell types. In this study, we investigate the impact of neuronal cell type on the firing outcome of ion channel mutations. Methods To this end, we simulated a diverse collection of single-compartment, conductance-based neuron models that differed in their composition of ionic currents. We systematically analyzed the effects of changes in ion current properties on firing in different neuronal types. Additionally, we simulated the effects of known mutations in KCNA1 gene encoding the KV1.1 potassium channel subtype associated with episodic ataxia type 1 (EA1). Results These simulations revealed that the outcome of a given change in ion channel properties on neuronal excitability depends on neuron type, i.e., the properties and expression levels of the unaffected ionic currents. Discussion Consequently, neuron-type specific effects are vital to a full understanding of the effects of channelopathies on neuronal excitability and are an important step toward improving the efficacy and precision of personalized medicine approaches.
Collapse
Affiliation(s)
- Nils A. Koch
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Lukas Sonnenberg
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Ulrike B. S. Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Stephan Lauxmann
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Jan Benda
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| |
Collapse
|
2
|
Kravchenko JA, Goldberg EM, Mattis J. Optogenetic and chemogenetic manipulation of seizure threshold in mice. STAR Protoc 2023; 4:102019. [PMID: 36640370 PMCID: PMC9846020 DOI: 10.1016/j.xpro.2022.102019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/07/2022] [Accepted: 12/23/2022] [Indexed: 01/15/2023] Open
Abstract
Here, we present a protocol using optogenetics or chemogenetics to assess the neuronal circuits contributing to seizure initiation. Both approaches allow for targeted control of neuronal populations in vivo and can be combined with experimental manipulations to acutely induce seizures in rodent models. We describe how to (1) introduce and (2) activate optogenetic or chemogenetic actuators while (3) inducing seizures via hyperthermia in a mouse model of epilepsy. This protocol can be adapted for use in other induced seizure models. For complete details on the use and execution of this protocol, please refer to Mattis et al. (2022).1.
Collapse
Affiliation(s)
- Julia A Kravchenko
- Department of Neurology, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.
| | - Ethan M Goldberg
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Joanna Mattis
- Department of Neurology, University of Michigan Medical Center, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.
| |
Collapse
|
3
|
Fedor FZ, Paraczky C, Ravasz L, Tóth K, Borhegyi Z, Somogyvári Z, Juhász G, Fekete Z. Electrophysiological and behavioral properties of 4-aminopyridine-induced epileptic activity in mice. Biol Futur 2021; 71:427-434. [PMID: 34554464 DOI: 10.1007/s42977-020-00047-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/14/2020] [Indexed: 10/23/2022]
Abstract
4-aminopyridine (4-AP) is a widely used drug that induces seizure activity in rodents, especially in rats, although there is no consensus in the literature on the dose to be used in mice. The aim of the present study was to investigate the effect of the intraperitoneal administration of 4-AP in two doses (4 and 10 mg/kg) in vivo. EEG, movement, and video recordings were made simultaneously in male B6 mice to specify the details of the seizures and to determine whether there is a suitable non-lethal dose for seizure induction and for further molecular studies. Seizure behavior in mice differs from that seen in rats, with no characteristic stages of epileptic seizures, but with spiking and seizure activity. Seizure activity, although produced at both doses without being lethal, induced different changes of the EEG pattern. Smaller dose induced a lower amplitude seizure activity, decreased spiking activity and later onset of seizures, while higher dose induced a much more intense brain seizure activity and severe trembling. It is concluded that the intraperitoneal administration of 4-AP at a dose of 10 mg/kg induces explicit seizure activity in mice which is repeatable and can be suitable for further molecular research.
Collapse
Affiliation(s)
- F Z Fedor
- Doctoral School of Chemical Engineering and Material Sciences, University of Pannonia, Veszprém, 8200, Hungary. .,ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, Eötvös Loránd University, Budapest, 1117, Hungary.
| | - C Paraczky
- Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - L Ravasz
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, Eötvös Loránd University, Budapest, 1117, Hungary
| | - K Tóth
- Laboratory of Molecular Neuroendocrinology, Institute of Experimental Medicine, 1083, Budapest, Hungary
| | - Z Borhegyi
- Department of Biochemistry, Eötvös Loránd University, Budapest, 1117, Hungary
| | - Z Somogyvári
- Theoretical Neuroscience and Complex Systems Research Group, Department of Computational Sciences, Wigner Research Centre for Physics, Budapest, 1121, Hungary
| | - G Juhász
- Department of Biochemistry, Eötvös Loránd University, Budapest, 1117, Hungary
| | - Z Fekete
- Research Group for Implantable Microsystems, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, 1083, Hungary.,Centre for Energy Research, Budapest, 1121, Hungary
| |
Collapse
|
4
|
Malkov A, Ivanov AI, Latyshkova A, Bregestovski P, Zilberter M, Zilberter Y. Activation of nicotinamide adenine dinucleotide phosphate oxidase is the primary trigger of epileptic seizures in rodent models. Ann Neurol 2019; 85:907-920. [PMID: 30937971 DOI: 10.1002/ana.25474] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 03/05/2019] [Accepted: 03/31/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Despite decades of epilepsy research, 30% of focal epilepsies remain resistant to antiseizure drugs, with effective drug development impeded by lack of understanding on how seizures are initiated. Here, we report the mechanism of seizure onset relevant to most seizures that are characteristic of focal epilepsies. METHODS Electric and metabolic network parameters were measured using several seizure models in mouse hippocampal slices and acutely induced seizures in rats in vivo to determine metabolic events occurring at seizure onset. RESULTS We show that seizure onset is associated with a rapid release of H2 O2 resulting from N-methyl-D-aspartate (NMDA) receptor-mediated activation of nicotinamide adenine dinucleotide phosphate oxidase (NOX). NOX blockade prevented the fast H2 O2 release as well as the direct current shift and seizurelike event induction in slices. Similarly, intracerebroventricular injection of NOX antagonists prevented acutely induced seizures in rats. INTERPRETATION Our results show that seizures are initiated by NMDA receptor-mediated NOX-induced oxidative stress and can be arrested by NOX inhibition. We introduce a novel use for blood-brain barrier-permeable NOX inhibitor with a significant potential to become the first seizure-specific medication. Thus, targeting NOX may provide a breakthrough treatment for focal epilepsies. ANN NEUROL 2019;85:907-920.
Collapse
Affiliation(s)
- Anton Malkov
- Aix-Marseille University, National Institute of Health and Medical Research, Institute of Neuroscience Systems, Mixed Unit of Research 1106, Marseille, France.,Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Anton I Ivanov
- Aix-Marseille University, National Institute of Health and Medical Research, Institute of Neuroscience Systems, Mixed Unit of Research 1106, Marseille, France
| | - Alexandra Latyshkova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Piotr Bregestovski
- Aix-Marseille University, National Institute of Health and Medical Research, Institute of Neuroscience Systems, Mixed Unit of Research 1106, Marseille, France.,Institute of Neurosciences, Kazan State Medical University, Kazan, Russia
| | - Misha Zilberter
- Gladstone Institute of Neurological Disease, San Francisco, CA
| | - Yuri Zilberter
- Aix-Marseille University, National Institute of Health and Medical Research, Institute of Neuroscience Systems, Mixed Unit of Research 1106, Marseille, France
| |
Collapse
|
5
|
Campos-Rodríguez C, Trujillo-Ferrara JG, Alvarez-Guerra A, Vargas IMC, Cuevas-Hernández RI, Andrade-Jorge E, Zamudio S, Juan ERS. Neuropharmacological Screening of Chiral and Non-chiral Phthalimide- Containing Compounds in Mice: in vivo and in silico Experiments. Med Chem 2019; 15:102-118. [DOI: 10.2174/1573406414666180525082038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 04/03/2018] [Accepted: 05/20/2018] [Indexed: 11/22/2022]
Abstract
Background:
Thalidomide, the first synthesized phthalimide, has demonstrated sedative-
hypnotic and antiepileptic effects on the central nervous system. N-substituted phthalimides
have an interesting chemical structure that confers important biological properties.
Objective:
Non-chiral (ortho and para bis-isoindoline-1,3-dione, phthaloylglycine) and chiral
phthalimides (N-substituted with aspartate or glutamate) were synthesized and the sedative, anxiolytic
and anticonvulsant effects were tested.
Method:
Homology modeling and molecular docking were employed to predict recognition of the
analogues by hNMDA and mGlu receptors. The neuropharmacological activity was tested with the
open field test and elevated plus maze (EPM). The compounds were tested in mouse models of
acute convulsions induced either by pentylenetetrazol (PTZ; 90 mg/kg) or 4-aminopyridine (4-AP;
10 mg/kg).
Results:
The ortho and para non-chiral compounds at 562.3 and 316 mg/kg, respectively, decreased
locomotor activity. Contrarily, the chiral compounds produced excitatory effects. Increased
locomotor activity was found with S-TGLU and R-TGLU at 100, 316 and 562.3 mg/kg,
and S-TASP at 316 and 562.3 mg/kg. These molecules showed no activity in the EPM test or PTZ
model. In the 4-AP model, however, S-TGLU (237.1, 316 and 421.7 mg/kg) as well as S-TASP
and R-TASP (316 mg/kg) lowered the convulsive and death rate.
Conclusion:
The chiral compounds exhibited a non-competitive NMDAR antagonist profile and
the non-chiral molecules possessed selective sedative properties. The NMDAR exhibited stereoselectivity
for S-TGLU while it is not a preference for the aspartic derivatives. The results appear to
be supported by the in silico studies, which evidenced a high affinity of phthalimides for the
hNMDAR and mGluR type 1.
Collapse
Affiliation(s)
- Carolina Campos-Rodríguez
- Physiology Department, Escuela Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Mexico City, Mexico
| | - José G. Trujillo-Ferrara
- Medicinal Biochemistry Department, Escuela Superior de Medicina Instituto Politecnico Nacional, Unidad Profesional Lázaro Cardenas del Río, Mexico City, Mexico
| | - Ameyali Alvarez-Guerra
- Physiology Department, Escuela Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Mexico City, Mexico
| | - Irán M. Cumbres Vargas
- Physiology Department, Escuela Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Mexico City, Mexico
| | - Roberto I. Cuevas-Hernández
- Medicinal Biochemistry Department, Escuela Superior de Medicina Instituto Politecnico Nacional, Unidad Profesional Lázaro Cardenas del Río, Mexico City, Mexico
| | - Erik Andrade-Jorge
- Medicinal Biochemistry Department, Escuela Superior de Medicina Instituto Politecnico Nacional, Unidad Profesional Lázaro Cardenas del Río, Mexico City, Mexico
| | - Sergio Zamudio
- Physiology Department, Escuela Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Mexico City, Mexico
| | - Eduardo R.-S. Juan
- Physiology Department, Escuela Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Mexico City, Mexico
| |
Collapse
|
6
|
Tóth Z, Mihály A, Mátyás A, Krisztin-Péva B. Non-competitive antagonists of NMDA and AMPA receptors decrease seizure-induced c-fos protein expression in the cerebellum and protect against seizure symptoms in adult rats. Acta Histochem 2018; 120:236-241. [PMID: 29478811 DOI: 10.1016/j.acthis.2018.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 02/12/2018] [Accepted: 02/14/2018] [Indexed: 02/04/2023]
Abstract
The aim of the present study was to examine the role of ionotropic glutamate receptors in the cerebellum during generalized seizures. Epileptic neuronal activation was evaluated through the immunohistochemical detection of c-fos protein in the cerebellar cortex. Generalized seizures were precipitated by the intraperitoneal injection of 4-aminopyridine. The animals were pretreated with the NMDA receptor antagonists MK-801 (2 mg/kg), amantadine (50 mg/kg), and the AMPA receptor antagonist GYKI 52466 hydrochloride (50 mg/kg). Two hours after 4-aminopyridine injection, the number of c-fos immunostained cell nuclei was counted in serial immunohistochemical sections of the cerebellar vermis. The number of c-fos immunostained cell nuclei in the granular layer decreased significantly in animals pretreated with the glutamate receptor antagonists compared to the untreated animals having convulsion. We can conclude that mossy fiber stimulation exerts its seizure-generating action mainly through the ionotropic glutamate receptors of the mossy fiber synapses. Both NMDA and AMPA receptor antagonists are effective in reducing glutamate-mediated postsynaptic effects in the cerebellar cortex.
Collapse
Affiliation(s)
- Zoltán Tóth
- Department of Anatomy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - András Mihály
- Department of Anatomy, Faculty of Medicine, University of Szeged, Szeged, Hungary.
| | - Adrienne Mátyás
- Department of Anatomy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Beáta Krisztin-Péva
- Department of Anatomy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| |
Collapse
|
7
|
Daanaa S, Abotsi WKM, Boakye-Gyasi E, Woode E. Anticonvulsant effect of the hydroethanolic leaf extract of Psydrax subcordata (DC.) Bridson in murine models. JOURNAL OF ETHNOPHARMACOLOGY 2018; 213:384-394. [PMID: 29183747 DOI: 10.1016/j.jep.2017.11.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/22/2017] [Accepted: 11/24/2017] [Indexed: 06/07/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Psydrax subcordata (DC.) Bridson is a tropical medicinal plant used traditionally for the management of epilepsy. However, there is little scientific evidence to support its use. AIM OF STUDY The current study investigated the anticonvulsant properties of the hydroethanolic leaf extract of Psydrax subcordata (PSE) in animal models. MATERIALS AND METHODS The anticonvulsant effects were evaluated in mouse models of acute seizures (pentylenetetrazole-, picrotoxin-, 4-aminopyridine-, strychnine- and maximal electroshock-induced seizure tests) and status epilepticus (Lithium/pilocarpine-induced SE). The role of GABAergic mechanisms in the actions of the extract was also examined by pre-treatment of animals with flumazenil in the pentylenetetrazole test. RESULTS The extract (30, 100 and 300mg/kg, p.o.) significantly delayed the onset and decreased the duration and frequency of pentylenetetrazole- and picrotoxin-convulsions. PSE also reduced the duration of tonic hind limb extensions in the maximal electroshock-induced seizure test. Furthermore, PSE pre-treatment significantly delayed the onset of seizures and improved survival in the 4-aminopyridine-induced seizure test. In the strychnine-induced seizure test, PSE treatment did not significantly affect the latency to convulsions and time until death when compared to controls. PSE exhibited anticonvulsant effects in the lithium/pilocarpine test by delaying the onset of seizures and status epilepticus as well as reducing the severity of seizures and mortality of mice. Again, the anticonvulsant effect of PSE (100mg/kg, p.o.) was blocked by pre-treatment with flumazenil in the PTZ test. CONCLUSION PSE has anticonvulsant activity in animal models, and this effect may be mediated, at least partly, through GABAergic mechanisms.
Collapse
Affiliation(s)
- Samuel Daanaa
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Wonder Kofi Mensah Abotsi
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Eric Boakye-Gyasi
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Eric Woode
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| |
Collapse
|
8
|
García-García L, Fernández de la Rosa R, Delgado M, Silván Á, Bascuñana P, Bankstahl JP, Gomez F, Pozo MA. Metyrapone prevents acute glucose hypermetabolism and short-term brain damage induced by intrahippocampal administration of 4-aminopyridine in rats. Neurochem Int 2017; 113:92-106. [PMID: 29203398 DOI: 10.1016/j.neuint.2017.11.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/13/2017] [Accepted: 11/28/2017] [Indexed: 11/29/2022]
Abstract
Intracerebral administration of the potassium channel blocker 4-aminopyridine (4-AP) triggers neuronal depolarization and intense acute seizure activity followed by neuronal damage. We have recently shown that, in the lithium-pilocarpine rat model of status epilepticus (SE), a single administration of metyrapone, an inhibitor of the 11β-hydroxylase enzyme, had protective properties of preventive nature against signs of brain damage and neuroinflammation. Herein, our aim was to investigate to which extent, pretreatment with metyrapone (150 mg/kg, i.p.) was also able to prevent eventual changes in the acute brain metabolism and short-term neuronal damage induced by intrahippocampal injection of 4-AP (7 μg/5 μl). To this end, regional brain metabolism was assessed by 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) positron emission tomography (PET) during the ictal period. Three days later, markers of neuronal death and hippocampal integrity and apoptosis (Nissl staining, NeuN and active caspase-3 immunohistochemistry), neurodegeneration (Fluoro-Jade C labeling), astrogliosis (glial fibrillary acidic protein (GFAP) immunohistochemistry) and microglia-mediated neuroinflammation (in vitro [18F]GE180 autoradiography) were evaluated. 4-AP administration acutely triggered marked brain hypermetabolism within and around the site of injection as well as short-term signs of brain damage and inflammation. Most important, metyrapone pretreatment was able to reduce ictal hypermetabolism as well as all the markers of brain damage except microglia-mediated neuroinflammation. Overall, our study corroborates the neuroprotective effects of metyrapone against multiple signs of brain damage caused by seizures triggered by 4-AP. Ultimately, our data add up to the consistent protective effect of metyrapone pretreatment reported in other models of neurological disorders of different etiology.
Collapse
Affiliation(s)
- Luis García-García
- Unidad de Cartografía Cerebral, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII n° 1, 28040 Madrid, Spain; Departamento de Farmacología, Farmacognosia y Biología Vegetal, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
| | - Rubén Fernández de la Rosa
- Unidad de Cartografía Cerebral, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII n° 1, 28040 Madrid, Spain
| | - Mercedes Delgado
- Unidad de Cartografía Cerebral, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII n° 1, 28040 Madrid, Spain
| | - Ágata Silván
- Unidad de Cartografía Cerebral, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII n° 1, 28040 Madrid, Spain
| | - Pablo Bascuñana
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg Str 1, 30625 Hannover, Germany
| | - Jens P Bankstahl
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg Str 1, 30625 Hannover, Germany
| | - Francisca Gomez
- Unidad de Cartografía Cerebral, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII n° 1, 28040 Madrid, Spain; Departamento de Farmacología, Farmacognosia y Biología Vegetal, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain
| | - Miguel A Pozo
- Unidad de Cartografía Cerebral, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Paseo Juan XXIII n° 1, 28040 Madrid, Spain; Departamento de Fisiología, Facultad de Medicina, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; Instituto Tecnológico PET, C/ Manuel Bartolomé Cossío n° 10, 28040 Madrid, Spain
| |
Collapse
|
9
|
Adongo DW, Mante PK, Kukuia KKE, Biney RP, Boakye-Gyasi E, Benneh CK, Ameyaw EO, Woode E. Anticonvulsant activity of Pseudospondias microcarpa (A. Rich) Engl. hydroethanolic leaf extract in mice: The role of excitatory/inhibitory neurotransmission and nitric oxide pathway. JOURNAL OF ETHNOPHARMACOLOGY 2017; 206:78-91. [PMID: 28528187 DOI: 10.1016/j.jep.2017.05.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 06/07/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Pseudospondias microcarpa (A. Rich) Engl. is a plant used for managing various diseases including central nervous system disorders. AIM OF THE STUDY This study explored the anticonvulsant activity of P. microcarpa hydroethanolic leaf extract (PME) as well as possible mechanism(s) of action in animal models. METHODS Effects of PME was assessed in electroconvulsive (the maximal electroshock and 6-Hz seizures) and chemoconvulsive (pentylenetetrazole-, picrotoxin-, isoniazid-, 4-aminopyridine-, and strychnine-induced seizures) models of epilepsy. In addition, effect of the extract on the nitric oxide pathway and GABAA receptor complex was evaluated. RESULTS The extract (30, 100 and 300mgkg-1, p.o.) significantly delayed the onset as well as decreased the duration and frequency of pentylenetetrazole-, picrotoxin- and strychnine-induced seizures. In addition, PME pre-treatment significantly improved survival in the 4-aminopyridine- and isoniazid-induced seizure tests. Furthermore, the extract protected against 6-Hz psychomotor seizures but had no effect in the maximal electroshock test. The anticonvulsant effect of PME (100mgkg-1, p.o.) was also reversed by pre-treatment with flumazenil, L-arginine or sildenafil. However, L-NAME or methylene blue (MB) augmented its effect. CONCLUSION Results show that PME has anticonvulsant activity and may probably be affecting GABAergic, glycinergic, NMDA, K+ channels and nitric oxide-cGMP pathways to exert its effect.
Collapse
Affiliation(s)
- Donatus W Adongo
- Department of Pharmacology, School of Medicine, University of Health and Allied Sciences, Ho, Ghana.
| | - Priscilla K Mante
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Kennedy K E Kukuia
- Department of Pharmacology and Toxicology, University of Ghana School of Pharmacy, University of Ghana, Accra, Ghana.
| | - Robert P Biney
- Department of Pharmacology, School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana.
| | - Eric Boakye-Gyasi
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Charles K Benneh
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Elvis O Ameyaw
- Department of Biomedical and Forensic Sciences, School of Biological Science, University of Cape Coast, Cape Coast, Ghana.
| | - Eric Woode
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| |
Collapse
|
10
|
Taiwe G, Moto F, Pale S, Kandeda A, Dawe A, Kouemou N, Ayissi E, Ngoupaye G, Njapdounke J, Nkantchoua G, Omam J, Pahaye D, Ngo Bum E. Extracts of Feretia apodanthera Del. demonstrated anticonvulsant activities against seizures induced by chemicals and maximal electroshock. Epilepsy Res 2016; 127:30-39. [DOI: 10.1016/j.eplepsyres.2016.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 08/02/2016] [Accepted: 08/11/2016] [Indexed: 11/16/2022]
|
11
|
Neuroprotective or neurotoxic effects of 4-aminopyridine mediated by KChIP1 regulation through adjustment of Kv 4.3 potassium channels expression and GABA-mediated transmission in primary hippocampal cells. Toxicology 2015; 333:107-117. [PMID: 25917026 DOI: 10.1016/j.tox.2015.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 04/05/2015] [Accepted: 04/22/2015] [Indexed: 11/21/2022]
Abstract
4-Aminopyridine (4-AP) is a potassium channel blocker used for the treatment of neuromuscular disorders. Otherwise, it has been described to produce a large number of adverse effects among them cell death mediated mainly by blockage of K(+) channels. However, a protective effect against cell death has also been described. On the other hand, Kv channel interacting protein 1 (KChIP1) is a neuronal calcium sensor protein that is predominantly expressed at GABAergic synapses and it has been related with modulation of K(+) channels, GABAergic transmission and cell death. According to this KChIP1 could play a key role in the protective or toxic effects induced by 4-AP. We evaluated, in wild type and KChIP1 silenced primary hippocampal neurons, the effect of 4-AP (0.25μM to 2mM) with or without semicarbazide (0.3M) co-treatment after 24h and after 14 days 4-AP alone exposure on cell viability, the effect of 4-AP (0.25μM to 2mM) on KChIP1 and Kv 4.3 potassium channels gene expression and GABAergic transmission after 24h treatment or after 14 days exposure to 4-AP (0.25μM to1μM). 4-AP induced cell death after 24h (from 1mM) and after 14 days treatment. We observed that 4-AP modulates KChIP1 which regulate Kv 4.3 channels expression and GABAergic transmission. Our study suggests that KChIP1 is a key gene that has a protective effect up to certain concentration after short-term treatment with 4-AP against induced cell injury; but this protection is erased after long term exposure, due to KChIP1 down-regulation predisposing cell to 4-AP induced damages. These data might help to explain protective and toxic effects observed after overdose and long term exposure.
Collapse
|
12
|
Medina-Ceja L, Sandoval-García F, Morales-Villagrán A, López-Pérez SJ. Rapid compensatory changes in the expression of EAAT-3 and GAT-1 transporters during seizures in cells of the CA1 and dentate gyrus. J Biomed Sci 2012; 19:78. [PMID: 22931236 PMCID: PMC3438021 DOI: 10.1186/1423-0127-19-78] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 08/21/2012] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Epilepsy is a neurological disorder produced by an imbalance between excitatory and inhibitory neurotransmission, in which transporters of both glutamate and GABA have been implicated. Hence, at different times after local administration of the convulsive drug 4-aminopyridine (4-AP) we analyzed the expression of EAAT-3 and GAT-1 transporter proteins in cells of the CA1 and dentate gyrus. METHODS Dual immunofluorescence was used to detect the co-localization of transporters and a neuronal marker. In parallel, EEG recordings were performed and convulsive behavior was rated using a modified Racine Scale. RESULTS By 60 min after 4-AP injection, EAAT-3/NeuN co-labelling had increased in dentate granule cells and decreased in CA1 pyramidal cells. In the latter, this decrease persisted for up to 180 min after 4-AP administration. In both the DG and CA1, the number of GAT-1 labeled cells increased 60 min after 4-AP administration, although by 180 min GAT-1 labeled cells decreased in the DG alone. The increase in EAAT-3/NeuN colabelling in DG was correlated with maximum epileptiform activity and convulsive behavior. CONCLUSIONS These findings suggest that a compensatory mechanism exists to protect against acute seizures induced by 4-AP, whereby EAAT-3/NeuN cells is rapidly up regulated in order to enhance the removal of glutamate from the extrasynaptic space, and attenuating seizure activity.
Collapse
Affiliation(s)
- Laura Medina-Ceja
- Laboratorio de Neurofisiología y Neuroquímica, Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Km, 15,5 Carretera Guadalajara-Nogales Predio "Las Agujas", Nextipac, Zapopan, Jalisco CP 45110, Mexico.
| | | | | | | |
Collapse
|
13
|
Morales-Villagrán A, Beltrán-Ramírez R, López-Pérez SJ, Palomera-Ávalos V, Medina-Ceja L. A Capillary Fraction Collector Coupled to a Fluorescence Reader: A Novel Device to Continuously Quantify Glutamate During Microdialysis. Neurochem Res 2012; 37:1457-64. [DOI: 10.1007/s11064-012-0736-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/12/2012] [Accepted: 02/20/2012] [Indexed: 10/28/2022]
|
14
|
Vera G, Tapia R. Activation of group III metabotropic glutamate receptors by endogenous glutamate protects against glutamate-mediated excitotoxicity in the hippocampus in vivo. J Neurosci Res 2012; 90:1055-66. [PMID: 22252898 DOI: 10.1002/jnr.23006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 10/21/2011] [Accepted: 11/17/2011] [Indexed: 11/10/2022]
Abstract
Perfusion of 4-aminopyridine (4-AP) by microdialysis in the hippocampus produces intense epileptiform behavioral and electrical activity and neurodegeneration, resulting from a stimulated release of glutamate from nerve endings. In contrast, accumulation of extracellular glutamate by blockade of its transport in vivo in anesthetized rats is innocuous, and studies in vitro in brain slices suggest that under these conditions glutamate may activate presynaptic group III metabotropic glutamate receptors (mGluRs) and inhibit its own release. Therefore, using microdialysis, EEG recording, and histological evaluation, we studied the effect of increased endogenous extracellular glutamate by blockade of its transport with pyrrolidine dicarboxylic acid (PDC) on the excitotoxic action of 4-AP in the hippocampus of awake rats. We found that up to a 20-fold increase in extracellular glutamate during >90 min with PDC does not induce any sign of excitotoxicity. On the contrary, this glutamate increase notably protected against the 4-AP-induced seizures and neurodegeneration, and, remarkably, this protection was dependent on the time of perfusion with PDC and thus on the duration of extracellular glutamate accumulation. To test whether this protective action was mediated by the activation of group III mGluRs, we used specific antagonists of these receptors and found that they clearly prevented the protective effect of PDC, without affecting the accumulation of extracellular glutamate. We conclude that the spillover of the excess extracellular glutamate activates presynaptic group III mGluRs and inhibits the stimulatory effect of 4-AP on its release, thus preventing the activation of postsynaptic N-methyl-D-aspartate receptors and its deleterious consequences.
Collapse
Affiliation(s)
- Gabriela Vera
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., México
| | | |
Collapse
|
15
|
Ghasemi M, Schachter SC. The NMDA receptor complex as a therapeutic target in epilepsy: a review. Epilepsy Behav 2011; 22:617-40. [PMID: 22056342 DOI: 10.1016/j.yebeh.2011.07.024] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 07/01/2011] [Accepted: 07/18/2011] [Indexed: 01/02/2023]
Abstract
A substantial amount of research has shown that N-methyl-D-aspartate receptors (NMDARs) may play a key role in the pathophysiology of several neurological diseases, including epilepsy. Animal models of epilepsy and clinical studies demonstrate that NMDAR activity and expression can be altered in association with epilepsy and particularly in some specific seizure types. NMDAR antagonists have been shown to have antiepileptic effects in both clinical and preclinical studies. There is some evidence that conventional antiepileptic drugs may also affect NMDAR function. In this review, we describe the evidence for the involvement of NMDARs in the pathophysiology of epilepsy and provide an overview of NMDAR antagonists that have been investigated in clinical trials and animal models of epilepsy.
Collapse
Affiliation(s)
- Mehdi Ghasemi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | | |
Collapse
|
16
|
Simultaneous glutamate and EEG activity measurements during seizures in rat hippocampal region with the use of an electrochemical biosensor. J Neurosci Methods 2008; 168:48-53. [DOI: 10.1016/j.jneumeth.2007.09.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2007] [Revised: 09/05/2007] [Accepted: 09/07/2007] [Indexed: 11/17/2022]
|
17
|
Antiepileptic effect of carbenoxolone on seizures induced by 4-aminopyridine: A study in the rat hippocampus and entorhinal cortex. Brain Res 2008; 1187:74-81. [DOI: 10.1016/j.brainres.2007.10.040] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 10/15/2007] [Accepted: 10/17/2007] [Indexed: 11/22/2022]
|
18
|
Abstract
Male mice (Mus musculus) from 15 standard inbred strains were exposed to a nearly constant concentration of ethanol (EtOH) vapor for 72 hr, averaging 1.59 +/- 0.03 mg EtOH/mL blood at withdrawal. EtOH- and air-exposed groups were tested hourly for handling-induced convulsions for 10 hr and at Hours 24 and 25. Strains differed markedly in the severity of withdrawal (after subtraction of control values), and by design these differences were independent of strain differences in EtOH metabolism. Correlation of strain mean withdrawal severity with other responses to EtOH supported previously reported genetic relationships of high EtOH withdrawal with low drinking, high conditioned taste aversion, low tolerance to EtOH-induced hypothermia, and high stimulated activity after low-dose EtOH. Also supported were the positive genetic correlations among EtOH, barbiturate, and benzodiazepine withdrawal. Sensitivity of naive mice to several chemical convulsant-induced seizures was also correlated with EtOH withdrawal.
Collapse
Affiliation(s)
- Pamela Metten
- Portland Alcohol Research Center, Veterans Affairs Medical Center, Portland, OR 97239, USA.
| | | |
Collapse
|
19
|
Corona JC, Tapia R. AMPA receptor activation, but not the accumulation of endogenous extracellular glutamate, induces paralysis and motor neuron death in rat spinal cord in vivo. J Neurochem 2004; 89:988-97. [PMID: 15140197 DOI: 10.1111/j.1471-4159.2004.02383.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanisms of motor neuron (MN) degeneration in amyotrophic lateral sclerosis (ALS) are unknown, but glutamate-mediated excitotoxicity may be involved. To examine directly this idea in vivo, we have used microdialysis in the rat lumbar spinal cord and showed that four- to fivefold increases in the concentration of endogenous extracellular glutamate during at least 1 h, by perfusion with the glutamate transport inhibitor L-2,4-trans-pyrrolidine-dicarboxylate, elicited no motor alterations or MN damage. Stimulation of glutamate release with 4-aminopyridine induced transitory ipsilateral hindlimb muscular twitches but no MN damage. In contrast, perfusion of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) did not modify glutamate levels but produced intense muscular spasms, followed by ipsilateral permanent hindlimb paralysis and a remarkable loss of MNs. These effects of AMPA were prevented by co-perfusion with the AMPA receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline. Perfusion with NMDA or kainate produced no motor effects or MN damage. Thus, the elevation of endogenous extracellular glutamate in vivo due to blockade of its transport is innocuous for spinal MNs. Because this resistance is observed under the same experimental conditions in which MNs are highly vulnerable to AMPA, these results indicate that excitotoxicity due to this mechanism might not be an important factor in the pathogenesis of ALS.
Collapse
Affiliation(s)
- Juan Carlos Corona
- Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, D. F., México
| | | |
Collapse
|
20
|
Ayala GX, Tapia R. Expression of heat shock protein 70 induced by 4-aminopyridine through glutamate-mediated excitotoxic stress in rat hippocampus in vivo. Neuropharmacology 2003; 45:649-60. [PMID: 12941378 DOI: 10.1016/s0028-3908(03)00230-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The intrahippocampal administration of 4-aminopyridine (4-AP) induces epileptic seizures and neurodegeneration, due probably to stimulation of glutamate release from synaptic terminals. We have studied the time course of the neurodegenerative changes produced by 4-AP, perfused through microdialysis cannulas in rat hippocampus, and correlated them with the expression of the inducible heat shock protein 70 (HSP70), detected immunocytochemically. Electroencephalographic seizure activity appeared immediately after the beginning of 4-AP perfusion. The first signs of histological neuronal damage were observed in CA1 and CA3 subfields of the perfused hippocampus 3 h after treatment and progressed until reaching a maximal neuronal loss at 24 h. In 4-AP-treated rats HSP70 was expressed mainly in neurons of the contralateral hippocampus, with a time course and cellular distribution very similar to the neurodegeneration observed in the perfused hippocampus, but no neuronal damage was observed. The N-methyl-D-aspartate (NMDA) receptor antagonists MK-801 and (3-phosphonopropyl)-piperazine-2-carboxylic acid prevented the seizures, the neurodegeneration and the expression of HSP70. These data demonstrate that the 4-AP-induced release of endogenous glutamate overactivates NMDA receptors in the perfused hippocampus and that the resulting neuronal hyperexcitability propagates to the contralateral hippocampus, generating a glutamate-mediated neuronal stress sufficient to induce the expression of HSP70 but not to produce neurodegeneration. These findings provide a useful model for investigating the relationships between neuronal hyperexcitation, neurodegeneration and the role of HSP expression.
Collapse
Affiliation(s)
- Gabriela X Ayala
- Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, AP 70-253, C.P. 04510 México D.F., Mexico
| | | |
Collapse
|
21
|
Salazar P, Tapia R, Rogawski MA. Effects of neurosteroids on epileptiform activity induced by picrotoxin and 4-aminopyridine in the rat hippocampal slice. Epilepsy Res 2003; 55:71-82. [PMID: 12948618 DOI: 10.1016/s0920-1211(03)00112-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The neurosteroids allopregnanolone (5alpha-pregnan-3alpha-ol-20-one; 5alpha,3alpha-P) and its 5beta-epimer pregnanolone (5beta,3alpha-P), and pregnenolone sulfate (PS) were examined for effects on spontaneous epileptiform discharges induced by 100 microM picrotoxin (PTX) and 55 microM 4-aminopyridine (4-AP) in the CA3 region of the rat hippocampal slice. At a concentration of 10 microM, 5alpha,3alpha-P partially reduced PTX-induced bursting and at 30 and 90 microM completely suppressed bursting. In contrast, 100 microM 5beta,3alpha-P failed to alter the discharge frequency. 5alpha,3alpha-P depressed 4-AP-induced bursting with similar potency as in the PTX model; 100 microM 5beta,3alpha-P was also partially effective. In the 4-AP model, 5alpha,3alpha-P inhibited both the more frequent predominantly positive-going potentials as well as the less frequent negative-going potentials that may be generated by synchronous GABAergic interneuron firing. PS enhanced the PTX bursting frequency and, in the 4-AP model, increased the frequency of negative potentials but did not alter the frequency of positive potentials. By itself, PS did not induce bursting. The effects of the steroids in the in vitro seizure models largely correspond with their activities on GABA(A) receptors; suppression of discharges may occur as a result of direct activation of these receptors rather than modulation of GABA-mediated synaptic responses. PTX and 4-AP-induced bursting in the hippocampal slice are useful models for directly assessing neurosteroid effects on seizure susceptibility under conditions that eliminate the factor of brain bioavailability.
Collapse
Affiliation(s)
- Patricia Salazar
- Epilepsy Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 49 Convent Drive Room 5A75 MSC 4457, Bethesda, MD 20892-4457, USA
| | | | | |
Collapse
|
22
|
Szakács R, Weiczner R, Mihály A, Krisztin-Péva B, Zádor Z, Zádor E. Non-competitive NMDA receptor antagonists moderate seizure-induced c-fos expression in the rat cerebral cortex. Brain Res Bull 2003; 59:485-93. [PMID: 12576146 DOI: 10.1016/s0361-9230(02)00965-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We examined the effects of non-competitive NMDA glutamate receptor antagonists on seizures elicited by 4-aminopyridine (4-AP), and in particular, on the expression of the transcription factor c-fos induced by these seizures. Induction of c-fos mRNA due to 4-AP-elicited seizures was ascertained by reverse transcription polymerase chain reaction in samples of the neocortex. Adult rats were pretreated with the NMDA receptor antagonists amantadine (40 mg/kg), ketamine (3mg/kg), dizocilpine (MK-801; 1mg/kg) or dextrometorphan (40 mg/kg); 4-AP (5mg/kg) was then injected i.p. Controls were treated with either antagonist only or with 4-AP only. Pretreatment with the antagonists (with the exception of amantadine) increased the latency of behavioural seizures, but not all of the antagonists caused symptomatic seizure protection. In the brains which were processed for Fos immunohistochemistry, quantitative evaluation of immunostained cells was performed in the neocortex and hippocampus. Treatment with either antagonist did not induce by itself c-fos expression, with the exception of amantadine, which caused slight Fos induction in the neocortex. Pretreatment with all the antagonists resulted in decrease of seizure-induced Fos immunoreactivity with respect to non-pretreated animals. Decrease of immunostained cells was significant in the neocortex, in the granule cell layer and hilus of the dentate gyrus, in hippocampal areas CA1 and CA2. MK-801, ketamine and dextrometorphan decreased significantly Fos immunoreactivity also in area CA3. The decrease of Fos immunostaining was not directly correlated with a suppression of behavioural seizures. The results support an important role of NMDA receptors in c-fos gene induction in acute 4-AP seizures.
Collapse
Affiliation(s)
- Réka Szakács
- Department of Psychiatry, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | | | | | | | | | | |
Collapse
|
23
|
Tutka P, Młynarczyk M, Zółkowska D, Kleinrok Z, Wielosz M, Czuczwar SJ. Nitric oxide and convulsions in 4-aminopyridine-treated mice. Eur J Pharmacol 2002; 437:47-53. [PMID: 11864638 DOI: 10.1016/s0014-2999(01)01600-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We studied whether N(G)-nitro-L-arginine (NNA), an inhibitor of nitric oxide (NO) synthase as well as L-arginine and molsidomine, two agents elevating NO, influenced convulsions caused by 4-aminopyridine, a K+ channel blocker in mice. NNA, in a dose known to decrease level of NO (40 mg x kg(-1)), enhanced the seizure susceptibility to intraperitoneal (i.p.) and intracerebroventricular (i.c.v.) 4-aminopyridine. L-arginine (500 mg x kg(-1)) and molsidomine (20 mg x kg(-1)) alone did not influence 4-aminopyridine-induced seizure activity. Surprisingly, the proconvulsant effect of NNA upon clonic and tonic seizures was potentiated by molsidomine (20 mg x kg(-1)). No influence of L-arginine on the proconvulsant effect of NNA was found. Taking into account the proconvulsant effect of NNA, an involvement of NO-mediated events in the mechanism of convulsive activity of 4-aminopyridine might be postulated. However, the ineffectiveness of L-arginine and molsidomine to suppress the convulsive activity of 4-aminopyridine as well as a paradoxical potentiation of the proconvulsant effect of NNA by molsidomine seem to exclude the impact of NO pathway on 4-aminopyridine-induced convulsions in mice. Our data suggest that the proconvulsant effect of NNA in this seizure model is caused by other, not related to NO, mechanisms.
Collapse
Affiliation(s)
- Piotr Tutka
- Department of Pharmacology and Toxicology, Medical University of Lublin, Jaczewskiego 8, PL-20-090, Lublin, Poland.
| | | | | | | | | | | |
Collapse
|
24
|
Peña F, Tapia R. Seizures and neurodegeneration induced by 4-aminopyridine in rat hippocampus in vivo: role of glutamate- and GABA-mediated neurotransmission and of ion channels. Neuroscience 2001; 101:547-61. [PMID: 11113304 DOI: 10.1016/s0306-4522(00)00400-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Infusion of the K(+) channel blocker 4-aminopyridine in the hippocampus induces the release of glutamate, as well as seizures and neurodegeneration. Since an imbalance between excitation and inhibition, as well as alterations of ion channels, may be involved in these effects of 4-aminopyridine, we have studied whether they are modified by drugs that block glutamatergic transmission or ion channels, or drugs that potentiate GABA-mediated transmission. The drugs were administered to anesthetized rats subjected to intrahippocampal infusion of 4-aminopyridine through microdialysis probes, with simultaneous collection of dialysis perfusates and recording of the electroencephalogram, and subsequent histological analysis. Ionotropic glutamate receptor antagonists clearly diminished the intensity of seizures and prevented the neuronal damage, but did not alter substantially the enhancement of extracellular glutamate induced by 4-aminopyridine. None of the drugs facilitating GABA-mediated transmission, including uptake blockers, GABA-transaminase inhibitors and agonists of the A-type receptor, was able to reduce the glutamate release, seizures or neuronal damage produced by 4-aminopyridine. In contrast, nipecotate, which notably increased extracellular levels of the amino acid, potentiated the intensity of seizures and the neurodegeneration. GABA(A) receptor antagonists partially reduced the extracellular accumulation of glutamate induced by 4-aminopyridine, but did not exert any protective action. Tetrodotoxin largely prevented the increase of extracellular glutamate, the electroencephalographic epileptic discharges and the neuronal death in the CA1 and CA3 hippocampal regions. Valproate and carbamazepine, also Na(+) channel blockers that possess general anticonvulsant action, failed to modify the three effects of 4-aminopyridine studied. The N-type Ca(2+) channel blocker omega-conotoxin, the K(+) channel opener diazoxide, and the non-specific ion channel blocker riluzole diminished the enhancement of extracellular glutamate and slightly protected against the neurodegeneration. However, the two former compounds did not antagonize the 4-aminopyridine-induced epileptiform discharges, and riluzole instead markedly increased the intensity and duration of the disharges. Moreover, at the highest dose tested (8mg/kg, i.p.), riluzole caused a 75% mortality of the rats. We conclude that 4-aminopyridine stimulates the release of glutamate from nerve endings and that the resultant augmented extracellular glutamate is directly related to the neurodegeneration and is involved in the generation of epileptiform discharges through the concomitant overactivation of glutamate receptors. Under these conditions, a facilitated GABA-mediated transmission may paradoxically boost neuronal hyperexcitation. Riluzole, a drug used to treat amyotrophic lateral sclerosis, seems to be toxic when combined with neuronal hyperexcitation.
Collapse
Affiliation(s)
- F Peña
- Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, AP 70-253, 04510, D.F., Mexico City, Mexico
| | | |
Collapse
|
25
|
Medina-Ceja L, Morales-Villagrán A, Tapia R. Action of 4-aminopyridine on extracellular amino acids in hippocampus and entorhinal cortex: a dual microdialysis and electroencehalographic study in awake rats. Brain Res Bull 2000; 53:255-62. [PMID: 11113578 DOI: 10.1016/s0361-9230(00)00336-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In order to study the role of amino acids in the hippocampus and the entorhinal cortex during the convulsive process induced by 4-aminopyridine (4-AP), we have used a device allowing the simultaneous microdialysis and the recording of their electrical activity of both regions in freely moving rats. We found that infusion of 4-AP into the entorhinal cortex resulted in a large increase in extracellular glutamate and glutamine and small increases in glycine and taurine levels. Likewise, infusion of 4-AP into the hippocampus resulted in a major increase in glutamate, as well as slight increases in taurine and glycine. In both infused regions the peak concentration of extracellular glutamate was observed 15 min after 4-AP administration. No significant changes were found in the non-infused hippocampus or entorhinal cortex of the same rats. Simultaneous electroencephalographic recordings showed intense epileptiform activity starting during 4-AP infusion and lasting for the rest of the experiment (1 h) in both the entorhinal cortex and the hippocampus. The discharges were characterized by poly-spikes and spike-wave complexes that propagated almost immediately to the other region studied. These findings suggest that increased glutamatergic synaptic function in the circuit that connects both regions is involved in the epileptic seizures induced by 4-AP.
Collapse
Affiliation(s)
- L Medina-Ceja
- Departamento de Biología Celular y Molecular, CUCBA, Universidad de Guadalajara, Guadalajara, Jal, Mexico
| | | | | |
Collapse
|
26
|
Sitges M, Nekrassov V, Guarneros A. Simultaneous action of MK-801 (dizclopine) on dopamine, glutamate, aspartate and GABA release from striatum isolated nerve endings. Brain Res 2000; 854:48-56. [PMID: 10784106 DOI: 10.1016/s0006-8993(99)02282-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The simultaneous effect of MK-801 on the baseline- and depolarization (20 microM veratridine or 30 mM high K+)-evoked release of endogenous dopamine, glutamate (Glu), aspartate (Asp), and GABA is investigated in the same preparation of rat striatum isolated nerve endings. MK-801, in the microM range, selectively increases the baseline and high K+ depolarization-evoked release of dopamine, without causing any effect on the baseline or on the high K+-evoked release of Glu, Asp and GABA. In addition to this selective action on dopamine release, MK-801 inhibits the veratridine depolarization-evoked release of all the neurotransmitters tested, including dopamine. In SBFI and fura-2 preloaded striatal synaptosomes, MK-801 inhibits the elevation of internal Na+ (Na(i)) and the elevation of internal Ca2+ (Ca(i)) induced by veratridine depolarization. The elevation of Ca(i) induced by high K+ depolarization is unchanged by MK-801. This study reveals two separate MK-801 actions. (1) The voltage-independent action, which increases dopamine release selectively, and might contribute to the effects of MK-801 on motor coordination. (2) The voltage-dependent action, which inhibits all the veratridine-evoked responses including the evoked release of the excitatory amino acids (which are particularly concentrated in striatum nerve endings), and might contribute to the anticonvulsant and neuroprotective effects of MK-801.
Collapse
Affiliation(s)
- M Sitges
- Depto. de Biología Celular, Instituto de Investigaciones Biomédicas, UNAM, México, DF, México.
| | | | | |
Collapse
|
27
|
Morales-Villagrán A, López-Pérez S, Medina-Ceja L, Tapia R. Cortical catecholamine changes and seizures induced by 4-aminopyridine in awake rats, studied with a dual microdialysis-electrical recording technique. Neurosci Lett 1999; 275:133-6. [PMID: 10568517 DOI: 10.1016/s0304-3940(99)00759-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We describe a rotatory electrical device that permits the simultaneous microdialysis and electroencephalographic (EEG) recording, by means of bipolar electrodes attached to the microdialysis probe, in two brain regions of awake rats. Using this device, we have found that the microdialysis infusion of 4-aminopyridine (4-AP) in the motor cerebral cortex produces intense behavioral convulsions and EEG seizures in both the infused and the contralateral cortex. This convulsant action is accompanied by a remarkable increase of extracellular dopamine (about 15-fold), norepinephrine (2.4-fold) and vanillylmandelic acid (1.8-fold) concentration in the infused cortex. Delayed increases of these amines were observed also in the contralateral cortex. The results suggest that 4-AP induces the release of catecholamines either through a direct effect on nerve endings or as a consequence of seizures.
Collapse
Affiliation(s)
- A Morales-Villagrán
- Departamento de Biología Celular y Molecular, CUCBA., Universidad de Guadalajara, Jal., Mexico
| | | | | | | |
Collapse
|
28
|
Dóczi J, Banczerowski-Pelyhe I, Barna B, Világi I. Effect of a glutamate receptor antagonist (GYKI 52466) on 4-aminopyridine-induced seizure activity developed in rat cortical slices. Brain Res Bull 1999; 49:435-40. [PMID: 10483921 DOI: 10.1016/s0361-9230(99)00079-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the present experiments we have tested the effect of the noncompetitive AMPA antagonist GYKI 52466 (20-80 microM) on spontaneous epileptic discharges developed as the consequence of 4-aminopyridine application in neocortex slices of adult rats. Parallel to the changes of spontaneous activity, the field potentials, evoked by electrical stimulation of the corpus callosum, were also analyzed. Glass microcapillary extracellular recording electrode was positioned in the third layer of the somatosensory cortex slice, while the stimulating electrode was placed at the border of the white and gray matter. 4-aminopyridine and GYKI 52466 were bath-applied. The application of 40 microM GYKI 52466 caused about 40% decrease in the frequency and the amplitude of spontaneous seizures as well as the duration of each discharges developed in 4-amino-pyridine. Pre-incubation with the AMPA antagonist effectively inhibited both the development of seizure activity and the maintenance of the discharges. GYKI 52466 also decreased the duration and amplitude of field responses evoked by stimulation of the corpus callosum. This inhibitory effect was dose-dependent. Our data in the in vitro cortex slice epilepsy model suggest that the non-competitive AMPA antagonist GYKI 52466 is a potent anticonvulsant and neuroprotective compound because it reduced the fully developed epileptic discharges or prevented their development.
Collapse
Affiliation(s)
- J Dóczi
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
| | | | | | | |
Collapse
|
29
|
Peña F, Tapia R. Relationships among seizures, extracellular amino acid changes, and neurodegeneration induced by 4-aminopyridine in rat hippocampus: a microdialysis and electroencephalographic study. J Neurochem 1999; 72:2006-14. [PMID: 10217278 DOI: 10.1046/j.1471-4159.1999.0722006.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
4-Aminopyridine is a powerful convulsant that induces the release of neurotransmitters, including glutamate. We report the effect of intrahippocampal administration of 4-aminopyridine at six different concentrations through microdialysis probes on EEG activity and on concentrations of extracellular amino acids and correlate this effect with histological changes in the hippocampus. 4-Aminopyridine induced in a concentration-dependent manner intense and frequent epileptic discharges in both the hippocampus and the cerebral cortex. The three highest concentrations used induced also a dose-dependent enhancement of extracellular glutamate, aspartate, and GABA levels and profound hippocampal damage. Neurodegenerative changes occurred in CA1, CA3, and CA4 subfields, whereas CA2 was spared. In contrast, microdialysis administration of a depolarizing K+ concentration and of tetraethylammonium resulted in increased amino acid levels but no epileptic activity and no or moderate neuronal damage. These results suggest that seizure activity induced by 4-aminopyridine is due to a combined action of excitatory amino acid release and direct stimulation of neuronal firing, whereas neuronal death is related to the increased glutamate release but is independent of seizure activity. In addition, it is concluded that the glutamate release-inducing effect of 4-aminopyridine results in excitotoxicity because it occurs at the level of nerve endings, thus permitting the interaction of glutamate with its postsynaptic receptors, which is probably not the case after K+ depolarization.
Collapse
Affiliation(s)
- F Peña
- Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, DF
| | | |
Collapse
|
30
|
Juhng KN, Kokate TG, Yamaguchi S, Kim BY, Rogowski RS, Blaustein MP, Rogawski MA. Induction of seizures by the potent K+ channel-blocking scorpion venom peptide toxins tityustoxin-K(alpha) and pandinustoxin-K(alpha). Epilepsy Res 1999; 34:177-86. [PMID: 10210033 DOI: 10.1016/s0920-1211(98)00111-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The scorpion venom peptide toxins tityustoxin-K(alpha) (TsTx-K(alpha)) and pandinustoxin-K(alpha) (PiTx-K(alpha)) are novel, highly potent and selective blockers of voltage-activated K+ channels. PiTx-K(alpha) preferentially blocks rapidly inactivating (A-type) K+ channels whereas TsTx-K(alpha) is selective for slowly inactivating (delayed rectifier-type) channels. K+ channel blockers are known to induce seizures, but the specific K channel types that can serve as convulsant targets are not well defined. To address this issue, we examined for convulsant activity the K+ channel type-specific scorpion toxins and the selective K+ channel antagonists 4-aminopyridine (4-AP), an inhibitor of A-type voltage-activated K+ channels, and paxilline, a selective blocker of large conductance (maxi K) Ca(2+)-activated K+ channels. Intracerebroventricular injection of recombinant TsTx-K(alpha) and PiTx-K(alpha) in mice produced limbic and clonic-tonic seizures. The severity of the seizures increased during the 60-min period following injection, culminating in continuous clonic seizure activity (status epilepticus), tonic hindlimb extension, and eventually in death. The estimated doses producing limbic and clonic seizures in 50% of animals (CD50) for TsTx-K(alpha) and PiTx-K(alpha) were 9 and 33 ng, respectively. 4-AP produced seizure activity similar to the toxins (CD50, 76 ng) whereas paxilline failed to induce seizures at doses up to 13.5 microg. Carbamazepine protected fully against the toxin- and 4-AP-induced seizures whereas phenytoin had variable activity against the clonic component although it was protective against tonic hindlimb extension. The AMPA receptor antagonist GYKI 52466 also conferred full protection against toxin-induced seizures, but the NMDA receptor antagonists (R)-CPP and dizocilpine failed to affect limbic and clonic seizures, although they protected against hindlimb extension. We conclude that selective blockade of delayed rectifier- or A-type voltage-activated K+ channels can produce limbic, clonic and tonic seizures, whereas blockade of maxi K-type Ca(2+)-activated K+ channels does not. The convulsant effects may be related to enhanced glutamate release and, in the case of the limbic and clonic convulsions, activation of AMPA receptors.
Collapse
Affiliation(s)
- K N Juhng
- Neuronal Excitability Section, Epilepsy Research Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1408, USA
| | | | | | | | | | | | | |
Collapse
|
31
|
Bui JD, Nammari DR, Buckley DL, Inglis BA, Silver XS, Mareci TH, Phillips MI. In vivo dynamics and distribution of intracerebroventricularly administered gadodiamide, visualized by magnetic resonance imaging. Neuroscience 1999; 90:1115-22. [PMID: 10218810 DOI: 10.1016/s0306-4522(98)00519-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Direct injections into the cerebroventricles have been extensively utilized in neurophysiological studies. Mapping the distribution of injectate after intracerebroventricular injection has been made only by post mortem analysis, and the dynamic distribution of injectate within the brain has not been well characterized. In this report, we apply contrast-enhanced magnetic resonance imaging to study the pharmacokinetics and extent of non-ionic gadodiamide transport into brain tissue in vivo after intracerebroventricular administration. The results indicate that intracerebroventricular injectate travels quickly throughout the ventricular system from the lateral ventricular site of injection to the fourth ventricle and foramina of Luschka and Magendie within 2 min. After this, the signal intensity begins to increase in the periventricular and paraventricular brain parenchyma. Contrast enhancement is visible 2 mm into the brain tissue from the ventricles. Quantitative analysis of the data shows that the transport of gadodiamide across the ependymal layer that lines the cerebrospinal fluid space characterized a rate constant of 0.066+/-0.017 min(-1). These results provide a better understanding of chemical transport and diffusion following direct injection into the cerebroventricles. They provide information on the in vivo dynamics of injectate after intracerebroventricular administration, and show that contrast enhanced magnetic resonance imaging may be used to more precisely define the target sites of chemicals after intracerebroventricular administration into the brain.
Collapse
Affiliation(s)
- J D Bui
- Department of Physiology, Center for Structural Biology, University of Florida, Gainesville 32610-0274, USA
| | | | | | | | | | | | | |
Collapse
|
32
|
Dorandeu F, Wetherell J, Pernot-Marino I, Tattersall JE, Fosbraey P, Lallement G. Effects of excitatory amino acid antagonists on dendrotoxin-induced increases in neurotransmitter release and epileptiform bursting in rat hippocampus in vitro. J Neurosci Res 1997; 48:499-506. [PMID: 9210519 DOI: 10.1002/(sici)1097-4547(19970615)48:6<499::aid-jnr2>3.0.co;2-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Alpha-dendrotoxin (alpha-DTx), a snake venom toxin which blocks several types of fast-activating voltage-dependent potassium channels, induces limbic seizures and neuronal damage when injected into the brain. The mechanisms underlying these convulsant and neuropathological actions are not fully understood. We have studied the effects of alpha-DTx on neurotransmitter release and electrical activity in rat hippocampal brain slices and the role of excitatory amino acid receptors in mediating these actions of the toxin. alpha-DTx increased the basal release of acetylcholine, glutamate, aspartate, and GABA in a concentration-dependent manner and induced epileptiform bursting in the CA1 and CA3 regions of the slice. The increase in neurotransmitter release was evident during the first 4 min after toxin addition, whereas the bursting appeared after a concentration-dependent delay (20-40 min with 250 nM toxin). The N-methyl-D-aspartate (NMDA) receptor antagonists AP5 and MK-801 had no effect on the frequency or amplitude of dendrotoxin-induced epileptiform bursts, but the non-NMDA antagonists CNQX and DNQX abolished bursting in both CA1 and CA3 within 4-6 min. In contrast, the toxin-induced increases in neurotransmitter release were not blocked by DNQX. This study has demonstrated that, following exposure to alpha-DTx, there is a rapid increase in the release of neurotransmitters which precedes the onset of epileptiform bursting in the hippocampus. Since DNQX abolished the bursting but had no effect on the increase in neurotransmitter release, these results suggest that DNQX blocks alpha-DTx-induced epileptiform activity by antagonism of postsynaptic non-NMDA receptors.
Collapse
Affiliation(s)
- F Dorandeu
- Department of Pharmacology, Centre de Recherches du Service de Sante des Armees, La Tronche, France
| | | | | | | | | | | |
Collapse
|