1
|
Kubová H, Mikulecká A, Mareš P. The outcome of early life status epilepticus—lessons from laboratory animals. Epilepsia Open 2022; 8 Suppl 1:S90-S109. [PMID: 36352789 PMCID: PMC10173850 DOI: 10.1002/epi4.12664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 10/18/2022] [Indexed: 11/11/2022] Open
Abstract
Status epilepticus (SE) is the most common neurologic emergency in children. Both clinical and laboratory studies have demonstrated that SE in early life can cause brain damage and permanent behavioral abnormalities, trigger epileptogenesis, and interfere with normal brain development. In experimental rodent models, the consequences of seizures are dependent upon age, the model used, and seizure duration. In studies involving neonatal and infantile animals, the model used, experimental design, conditions during the experiment, and manipulation of animals can significantly affect the course of the experiments as well as the results obtained. Standardization of laboratory approaches, harmonization of scientific methodology, and improvement in data collection can improve the comparability of data among laboratories.
Collapse
Affiliation(s)
- Hana Kubová
- Developmental Epileptology Institute of Physiology of the Czech Academy of Science Prague Czech Republic
| | - Anna Mikulecká
- Developmental Epileptology Institute of Physiology of the Czech Academy of Science Prague Czech Republic
| | - Pavel Mareš
- Developmental Epileptology Institute of Physiology of the Czech Academy of Science Prague Czech Republic
| |
Collapse
|
2
|
Bicakci AO, Sarkar M, Chang YH, Kahl E, Ragazzi L, Moldes-Anaya A, Fendt M. Anxiolytic-like Effects of the Positive GABAB Receptor Modulator GS39783 Correlate with Mice’s Individual Basal Anxiety and Stress Reactivity. Pharmaceuticals (Basel) 2022; 15:ph15020233. [PMID: 35215345 PMCID: PMC8878184 DOI: 10.3390/ph15020233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 12/10/2022] Open
Abstract
Positive gamma-aminobutyric acid type B (GABAB) receptor modulators such as GS39783 have showed anxiolytic-like effects in several studies while such effects were absent in other studies. These conflicting findings led us hypothesize that the anxiolytic-like effects of such compounds depend on the individual basal anxiety and/or the anxiogenic properties of the used tests. The present study addresses this hypothesis by testing GS39783 effects on mice’s anxiety-like behavior in a light–dark box. We found that GS39783 had no effects on a whole-group level. However, after grouping the mice for their basal anxiety, GS39783 reduced anxiety-like behavior in the subgroup with highest basal anxiety. Moreover, GS39783 effects correlated with individual basal anxiety. Next, the anxiogenic properties of the light–dark box test were increased by prior stress exposure. Again, GS39783 was not effective on a whole-group level. However, GS39783 had an anxiolytic-like effect in the most stress-responsive subgroup. Moreover, GS39783 effects correlated with individual stress responsiveness. Finally, we show that GS39783 brain levels were within a behaviorally relevant range. Overall, our study demonstrates that GS39783 effects depend on individual basal anxiety and stress responsiveness. This suggests that anxiety tests should generally be designed to capture individual basal anxiety and/or stress responsiveness as well as individual compound effects.
Collapse
Affiliation(s)
- Ahmet Oguzhan Bicakci
- Integrative Neuroscience Master Program, Institute of Biology, Faculty of Natural Sciences, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (A.O.B.); (M.S.); (Y.-H.C.)
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany;
| | - Mousumi Sarkar
- Integrative Neuroscience Master Program, Institute of Biology, Faculty of Natural Sciences, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (A.O.B.); (M.S.); (Y.-H.C.)
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany;
| | - Yu-Hsin Chang
- Integrative Neuroscience Master Program, Institute of Biology, Faculty of Natural Sciences, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (A.O.B.); (M.S.); (Y.-H.C.)
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany;
| | - Evelyn Kahl
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany;
| | - Lorenzo Ragazzi
- Neurobiology Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, 9019 Tromsø, Norway;
| | - Angel Moldes-Anaya
- Nuclear Medicine and Radiation Biology Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, 9037 Tromsø, Norway;
- Cyclotron and Radiochemistry Unit, The PET Imaging Center, University Hospital of North Norway, 9038 Tromsø, Norway
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany;
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
- Correspondence: ; Tel.: +49-391-67-21982
| |
Collapse
|
3
|
Mareš P, Kubová H. Interaction of GABA A and GABA B antagonists after status epilepticus in immature rats. Epilepsy Behav 2020; 102:106683. [PMID: 31760199 DOI: 10.1016/j.yebeh.2019.106683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 10/13/2019] [Accepted: 11/02/2019] [Indexed: 10/25/2022]
Abstract
Among neurotransmitter systems affected by status epilepticus (SE) in adult rats are both GABAergic systems. To analyze possible changes of GABAA and GABAB systems in developing rats lithium-pilocarpine SE was induced at postnatal day 12 (P12). Seizures were elicited by a GABAA antagonist pentylenetetrazol (PTZ) 3, 6, 9, and 13 days after SE (i.e., in P15, P18, P21, and P25 rats), and their possible potentiation by a GABAB receptor antagonist CGP46381 was studied. Pilocarpine was replaced by saline in control animals (lithium-paraldehyde [LiPAR]). Pentylenetetrazol in a dose of 50 mg/kg s.c. elicited generalized seizures in nearly all 15-day-old naive rats and in 40% of 18-day-old ones but not in older animals. After SE, PTZ no longer elicited seizures in these two younger groups, i.e., sensitivity of GABAA system was diminished. The GABAB antagonist exhibited proconvulsant effect in P15 and P18 SE as well as LiPAR rats returning the incidence of PTZ-induced seizures to values of control animals. A decrease in the incidence of minimal clonic seizures was seen in P21 LiPAR animals; these seizures in the oldest group were not affected. Change of the effect from proconvulsant to anticonvulsant (or at least to no action) took place before postnatal day 21. Both SE and LiPAR animals exhibited similar changes but their intensity differed, effects in LiPAR controls were usually more expressed than in SE rats.
Collapse
Affiliation(s)
- Pavel Mareš
- Department of Developmental Epileptology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
| | - Hana Kubová
- Department of Developmental Epileptology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
| |
Collapse
|
4
|
Mareš P. Participation of GABA B receptors in cortical postictal excitability in immature rats. Eur J Pharmacol 2018; 818:26-29. [PMID: 29032104 DOI: 10.1016/j.ejphar.2017.10.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 10/05/2017] [Accepted: 10/12/2017] [Indexed: 11/29/2022]
Abstract
Arrest of seizures is due to an active inhibition and is followed in mature brain by period of refractoriness markedly present one min after the end of seizures. To study changes in cortical excitability after epileptic seizures we used electrical stimulation of sensorimotor cortical area in immature rats - 25-day-old ones with mature postictal refractoriness and 12-day-old where postictal potentiation of afterdischarges (ADs) is present instead of refractoriness at one minute after the end of the conditioning AD. GABAB receptor antagonist CGP35348 was found to partly suppress postictal refractoriness. In present study not only an antagonist CGP46381 (3 and 10mg/kg i.p.) but also positive allosteric modulator of GABAB receptors CGP7930 (20 and 40mg/kg i.p.) were used to study the role of GABAB receptors in both age groups. They were injected immediately after testing AD and 10min later the two stimulations were repeated. CGP46381 partly antagonized postictal refractoriness in 25-day-old rats but did not significantly affect ADs in 12-day-old animals. CGP7930 did not significantly change ADs duration in either age group. GABAB receptors participate in mechanism of postictal refractoriness but did not play an important role in 12-day-old rats where potentiation instead of refractoriness is present.
Collapse
Affiliation(s)
- Pavel Mareš
- Department of Developmental Epileptology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
| |
Collapse
|
5
|
TERUNUMA M. Diversity of structure and function of GABA B receptors: a complexity of GABA B-mediated signaling. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2018; 94:390-411. [PMID: 30541966 PMCID: PMC6374141 DOI: 10.2183/pjab.94.026] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 10/09/2018] [Indexed: 05/24/2023]
Abstract
γ-aminobutyric acid type B (GABAB) receptors are broadly expressed in the nervous system and play an important role in neuronal excitability. GABAB receptors are G protein-coupled receptors that mediate slow and prolonged inhibitory action, via activation of Gαi/o-type proteins. GABAB receptors mediate their inhibitory action through activating inwardly rectifying K+ channels, inactivating voltage-gated Ca2+ channels, and inhibiting adenylate cyclase. Functional GABAB receptors are obligate heterodimers formed by the co-assembly of R1 and R2 subunits. It is well established that GABAB receptors interact not only with G proteins and effectors but also with various proteins. This review summarizes the structure, subunit isoforms, and function of GABAB receptors, and discusses the complexity of GABAB receptors, including how receptors are localized in specific subcellular compartments, the mechanism regulating cell surface expression and mobility of the receptors, and the diversity of receptor signaling through receptor crosstalk and interacting proteins.
Collapse
Affiliation(s)
- Miho TERUNUMA
- Division of Oral Biochemistry, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| |
Collapse
|
6
|
Zimcikova E, Simko J, Karesova I, Kremlacek J, Malakova J. Behavioral effects of antiepileptic drugs in rats: Are the effects on mood and behavior detectable in open-field test? Seizure 2017; 52:35-40. [DOI: 10.1016/j.seizure.2017.09.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 09/11/2017] [Accepted: 09/19/2017] [Indexed: 11/30/2022] Open
|
7
|
Brown JW, Moeller A, Schmidt M, Turner SC, Nimmrich V, Ma J, Rueter LE, van der Kam E, Zhang M. Anticonvulsant effects of structurally diverse GABA(B) positive allosteric modulators in the DBA/2J audiogenic seizure test: Comparison to baclofen and utility as a pharmacodynamic screening model. Neuropharmacology 2015; 101:358-69. [PMID: 26471422 DOI: 10.1016/j.neuropharm.2015.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/31/2015] [Accepted: 10/04/2015] [Indexed: 02/02/2023]
Abstract
The GABA(B) receptor has been indicated as a promising target for multiple CNS-related disorders. Baclofen, a prototypical orthosteric agonist, is used clinically for the treatment of spastic movement disorders, but is associated with unwanted side-effects, such as sedation and motor impairment. Positive allosteric modulators (PAM), which bind to a topographically-distinct site apart from the orthosteric binding pocket, may provide an improved side-effect profile while maintaining baclofen-like efficacy. GABA, the major inhibitory neurotransmitter in the CNS, plays an important role in the etiology and treatment of seizure disorders. Baclofen is known to produce anticonvulsant effects in the DBA/2J mouse audiogenic seizure test (AGS), suggesting it may be a suitable assay for assessing pharmacodynamic effects. Little is known about the effects of GABA(B) PAMs, however. The studies presented here sought to investigate the AGS test as a pharmacodynamic (PD) screening model for GABA(B) PAMs by comparing the profile of structurally diverse PAMs to baclofen. GS39783, rac-BHFF, CMPPE, A-1295120 (N-(3-(4-(4-chloro-3-fluorobenzyl)-6-methoxy-3,5-dioxo-4,5-dihydro-1,2,4-triazin-2(3H)-yl)phenyl)acetamide), and A-1474713 (N-(3-(4-(4-chlorobenzyl)-3,5-dioxo-4,5-dihydro-1,2,4-triazin-2(3H)-yl)phenyl)acetamide) all produced robust, dose-dependent anticonvulsant effects; a similar profile was observed with baclofen. Pre-treatment with the GABA(B) antagonist SCH50911 completely blocked the anticonvulsant effects of baclofen and CMPPE in the AGS test, indicating such effects are likely mediated by the GABA(B) receptor. In addition to the standard anticonvulsant endpoint of the AGS test, video tracking software was employed to assess potential drug-induced motor side-effects during the acclimation period of the test. This analysis was sensitive to detecting drug-induced changes in total distance traveled, which was used to establish a therapeutic index (TI = hypoactivity/anticonvulsant effects). Calculated TIs for A-1295120, CMPPE, rac-BHFF, GS39783, and A-1474713 were 5.31x, 5.00x, 4.74x, 3.41x, and 1.83x, respectively, whereas baclofen was <1. The results presented here suggest the DBA/2J mouse AGS test is a potentially useful screening model for detecting PD effects of GABA(B) PAMs and can provide an initial read-out on target-related motor side-effects. Furthermore, an improved TI was observed for PAMs compared to baclofen, indicating the PAM approach may be a viable therapeutic alternative to baclofen.
Collapse
Affiliation(s)
- Jordan W Brown
- Neuroscience Discovery, AbbVie, Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States.
| | - Achim Moeller
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Martin Schmidt
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Sean C Turner
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Volker Nimmrich
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Junli Ma
- Drug Metabolism and Pharmacokinetics, AbbVie, Inc., North Chicago, IL 60064, United States
| | - Lynne E Rueter
- Neuroscience Discovery, AbbVie, Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States
| | - Elizabeth van der Kam
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Min Zhang
- Neuroscience Discovery, AbbVie, Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States
| |
Collapse
|
8
|
Szczurowska E, Mareš P. Different action of a specific NR2B/NMDA antagonist Ro 25-6981 on cortical evoked potentials and epileptic afterdischarges in immature rats. Brain Res Bull 2015; 111:1-8. [DOI: 10.1016/j.brainresbull.2014.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/30/2014] [Accepted: 11/04/2014] [Indexed: 01/13/2023]
|
9
|
Mareš P, Tichá K, Mikulecká A. Anticonvulsant and behavioral effects of muscimol in immature rats. Brain Res 2014; 1582:227-36. [PMID: 25084038 DOI: 10.1016/j.brainres.2014.07.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/21/2014] [Accepted: 07/23/2014] [Indexed: 10/25/2022]
Abstract
Potentiation of GABAergic inhibition is a mechanism of action of many antiepileptic drugs. The potential use of an agonist of GABAA receptors, muscimol, as an antiepileptic drug was studied in immature rats by assessing anticonvulsant activity and side effects on motor activities. Anticonvulsant action was tested in two models of seizures (pentetrazol-induced convulsions and cortical epileptic afterdischarges). Off target effect on motor performance was assessed in a battery of tests and in the open field in three age groups (12-, 18- and 25-day-old rats). Muscimol was administered in doses from 0.1 to 1mg/kg i.p. Only the 1 mg/kg dose exhibited marked anticonvulsant effect against pentetrazol-induced convulsions in 12- and 18-day-old rats, proconvulsant effect was observed in the second model in 18- and 25-day-old rats as prolongation of afterdischarges. Even the 0.5 mg/kg dose suppressed spontaneous locomotion and heavily compromised motor performance. The effect on motor activity was marked in the youngest group and decreased with age. Due to the low anticonvulsant potency and serious side effects, systemic administration of a competitive agonist of GABAA receptors in immature animals is not a promising strategy for new anticonvulsants.
Collapse
Affiliation(s)
- Pavel Mareš
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences, Czech Republic.
| | - Kateřina Tichá
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences, Czech Republic; Charles University, 2nd Medical Faculty, Prague, Czech Republic
| | - Anna Mikulecká
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences, Czech Republic
| |
Collapse
|
10
|
Mareš P. A1 not A2A adenosine receptors play a role in cortical epileptic afterdischarges in immature rats. J Neural Transm (Vienna) 2014; 121:1329-36. [PMID: 24824175 DOI: 10.1007/s00702-014-1234-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 04/28/2014] [Indexed: 02/07/2023]
Abstract
Endo- as well as exogenous adenosine exhibits anticonvulsant action. Participation of individual types of adenosine receptors was studied in present experiments in immature rats. Cortical epileptic afterdischarges were used as a model in rat pups 12, 18 and 25 days old. CCPA, an agonist of A1 adenosine receptors, decreased markedly duration of afterdischarges whereas DPCPX, an antagonist of A1 receptors, exhibited strong proconvulsant action. Action of either drug was best expressed in 12-day-old rats and it decreased with age. Drugs influencing A2A adenosine receptors (agonist CGS21680 and antagonist ZM241385) did not exhibit systematic effects in our model. Motor phenomena accompanying cortical stimulation or epileptic afterdischarge were never influenced by any of the four drugs studied. A1 adenosine receptors are important in the model of cortical seizures, especially in the youngest group studied.
Collapse
Affiliation(s)
- Pavel Mareš
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 14220, Prague 4, Czech Republic,
| |
Collapse
|
11
|
Lang M, Moradi-Chameh H, Zahid T, Gane J, Wu C, Valiante T, Zhang L. Regulating hippocampal hyperexcitability through GABAB Receptors. Physiol Rep 2014. [PMID: 24771688 PMCID: PMC4001873 DOI: 10.1002/phy2.278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Disturbances of GABAergic inhibition are a major cause of epileptic seizures. GABA exerts its actions via ionotropic GABAA receptors and metabotropic G protein‐coupled GABAB receptors. Malfunction of GABAA inhibition has long been recognized in seizure genesis but the role of GABAB receptors in controlling seizure activity is still not well understood. Here, we examined the anticonvulsive, or inhibitory effects, of GABAB receptors in a mouse model of hippocampal kindling as well as mouse hippocampal slices through the use of GS 39783, a positive allosteric GABAB receptor modulator, and CGP 55845, a selective GABAB receptor antagonist. When administered via intraperitoneal injections in kindled mice, GS 39783 (5 mg/kg) did not attenuate hippocampal EEG discharges, but did reduce aberrant hippocampal spikes, whereas CGP 55845 (10 mg/kg) prolonged hippocampal discharges and increased spike incidences. When examined in hippocampal slices, neither GS 39783 at 5 μmol/L nor the GABAB receptor agonist baclofen at 0.1 μmol/L alone significantly altered repetitive excitatory field potentials, but GS 39783 and baclofen together reversibly abolished these field potentials. In contrast, CGP 55845 at 1 μmol/L facilitated induction and incidence of these field potentials. In addition, CGP 55845 attenuated the paired pulse depression of CA3 population spikes and increased the frequency of EPSCs in individual CA3 pyramidal neurons. Collectively, these data suggest that GABABB receptors regulate hippocampal hyperexcitability by inhibiting CA3 glutamatergic synapses. We postulate that positive allosteric modulation of GABAB receptors may be effective in reducing seizure‐related hyperexcitability. GABAB positive modulator GS 39783 attenuated, whereas GABAB antagonist CGP55845 facilitated hippocampal EEG spikes in kindled mice and excitatory field potentials in hippocampal slices. We postulate that GABAB receptors may inhibit CA3 glutamate synapses and hence regulate hippocampal hyperexcitability.
Collapse
Affiliation(s)
- Min Lang
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
| | - Homeira Moradi-Chameh
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
- Department of Physiology; University of Tarbiat Modares; Tehran Iran
| | - Tariq Zahid
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
| | - Jonathan Gane
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
| | - Chiping Wu
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
| | - Taufik Valiante
- Department of Surgery (Division of Neurosurgery); University of Toronto; Toronto Ontario Canada
| | - Liang Zhang
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
- Department of Medicine (Division of Neurology); University of Toronto; Toronto Ontario Canada
| |
Collapse
|
12
|
Mareš P. Proconvulsant action of two GABA(B) receptor antagonists is age-dependent. Physiol Res 2013; 62:S109-14. [PMID: 24329690 DOI: 10.33549/physiolres.932599] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Antagonists of GABA(B) receptors are expected to have proconvulsant action also in developing brain. Two antagonists (CGP55845 and CGP46381) were tested in a model of cortical epileptic afterdischarges (ADs) in 12-, 18- and 25-day-old rat pups with implanted electrodes. CGP55845 was dissolved in dimethylsulfoxide and the results demonstrated marked proconvulsant action of this solvent which masked possible action of the antagonist. Water soluble antagonist CGP46381 led to marked potentiation of ADs in 12-day-old animals, its action decreased with age, it was negligible in 25-day-old rats. Our results demonstrated important inhibitory role of GABA(B) receptors at very early stages of maturation.
Collapse
Affiliation(s)
- P Mareš
- Department of Developmental Epileptology, Institute of Physiology AS CR, Prague, Czech Republic.
| |
Collapse
|