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Santos VR, Hammack R, Wicker E, N'Gouemo P, Forcelli PA. Divergent Effects of Systemic and Intracollicular CB Receptor Activation Against Forebrain and Hindbrain-Evoked Seizures in Rats. Front Behav Neurosci 2020; 14:595315. [PMID: 33328922 PMCID: PMC7718031 DOI: 10.3389/fnbeh.2020.595315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/19/2020] [Indexed: 12/26/2022] Open
Abstract
Cannabinoid (CB) receptor agonists are of growing interest as targets for anti-seizure therapies. Here we examined the effect of systemic administration of the CB receptor agonist WIN 55,212-2 (WIN) against audiogenic seizures (AGSs) in the Genetically Epilepsy Prone Rat (GEPR)-3 strain, and against seizures evoked focally from the Area Tempestas (AT). We compared these results to the effect of focal administration of the CB1/2 receptor agonist CP 55940 into the deep layers of the superior colliculus (DLSC), a brain site expressing CB1 receptors. While systemic administration of WIN dose-dependently decreased AGS in GEPR-3s, it was without effect in the AT model. By contrast, intra-DLSC infusion of CP 55940 decreased seizures in both models. To determine if the effects of systemic WIN were dependent upon activation of CB1 receptors in the DSLC, we next microinjected the CB1 receptor antagonist SR141716, before WIN systemic treatment, and tested animals for AGS susceptibility. The pretreatment of the DLSC with SR141716 was without effect on its own and did not alter the anti-convulsant action of WIN systemic administration. Thus, while CB receptors in the DLSC are a potential site of anticonvulsant action, they are not necessary for the effects of systemically administered CB agonists.
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Affiliation(s)
- Victor R Santos
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, United States.,Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Robert Hammack
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, United States.,Department of Cellular and Integrated Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Evan Wicker
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, United States
| | - Prosper N'Gouemo
- Department of Pediatrics, Georgetown University School of Medicine, Washington, DC, United States.,Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States.,Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC, United States
| | - Patrick A Forcelli
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, United States.,Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States.,Department of Neuroscience, Georgetown University School of Medicine, Washington, DC, United States
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Cannabinoids affect the mouse visual acuity via the cannabinoid receptor type 2. Sci Rep 2020; 10:15819. [PMID: 32978469 PMCID: PMC7519129 DOI: 10.1038/s41598-020-72553-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/02/2020] [Indexed: 12/18/2022] Open
Abstract
Recently, there have been increasing indications that the endocannabinoid (eCB) system is involved in vision. Multiple research teams studied the cannabinoid receptor type 2 (CB2R) expression and function in the mouse retina. Here, we examined the consequence of CB2R modulation on visual acuity using genetic and pharmacologic tools. We found that Cnr2 knockout mice show an enhanced visual acuity, CB2R activation decreased visual acuity while CB2R blockade with the inverse agonist AM630 increased it. The inhibition of 2-arachidonylglycerol (2-AG) synthesis and degradation also greatly increased and decreased visual acuity, respectively. No differences were seen when the cannabinoid receptor type 1 (CB1R) was deleted, blocked or activated implying that CB2R exclusively mediates cannabinoid modulation of the visual acuity. We also investigated the role of cannabinoids in retinal function using electroretinography (ERG). We found that modulating 2-AG levels affected many ERG components, such as the a-wave and oscillatory potentials (OPs), suggesting an impact on cones and amacrine cells. Taken together, these results reveal that CB2R modulates visual acuity and that eCBs such as 2-AG can modulate both visual acuity and retinal sensitivity. Finally, these findings establish that CB2R is present in visual areas and regulates vision-related functions.
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An D, Peigneur S, Hendrickx LA, Tytgat J. Targeting Cannabinoid Receptors: Current Status and Prospects of Natural Products. Int J Mol Sci 2020; 21:E5064. [PMID: 32709050 PMCID: PMC7404216 DOI: 10.3390/ijms21145064] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023] Open
Abstract
Cannabinoid receptors (CB1 and CB2), as part of the endocannabinoid system, play a critical role in numerous human physiological and pathological conditions. Thus, considerable efforts have been made to develop ligands for CB1 and CB2, resulting in hundreds of phyto- and synthetic cannabinoids which have shown varying affinities relevant for the treatment of various diseases. However, only a few of these ligands are clinically used. Recently, more detailed structural information for cannabinoid receptors was revealed thanks to the powerfulness of cryo-electron microscopy, which now can accelerate structure-based drug discovery. At the same time, novel peptide-type cannabinoids from animal sources have arrived at the scene, with their potential in vivo therapeutic effects in relation to cannabinoid receptors. From a natural products perspective, it is expected that more novel cannabinoids will be discovered and forecasted as promising drug leads from diverse natural sources and species, such as animal venoms which constitute a true pharmacopeia of toxins modulating diverse targets, including voltage- and ligand-gated ion channels, G protein-coupled receptors such as CB1 and CB2, with astonishing affinity and selectivity. Therefore, it is believed that discovering novel cannabinoids starting from studying the biodiversity of the species living on planet earth is an uncharted territory.
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Affiliation(s)
| | | | | | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium; (D.A.); (S.P.); (L.A.H.)
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Luszczki JJ, Panasiuk A, Zagaja M, Karwan S, Bojar H, Plewa Z, Florek-Łuszczki M. Polygonogram and isobolographic analysis of interactions between various novel antiepileptic drugs in the 6-Hz corneal stimulation-induced seizure model in mice. PLoS One 2020; 15:e0234070. [PMID: 32479532 PMCID: PMC7263629 DOI: 10.1371/journal.pone.0234070] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/17/2020] [Indexed: 12/11/2022] Open
Abstract
Pharmacotherapy with two antiepileptic drugs in combination is usually prescribed to epilepsy patients with refractory seizures. The choice of antiepileptic drugs in combination should be based on synergistic cooperation of the drugs with respect to suppression of seizures. The selection of synergistic interactions between antiepileptic drugs is challenging issue for physicians, especially, if 25 antiepileptic drugs are currently available and approved to treat epilepsy patients. The aim of this study was to determine all possible interactions among 5 second-generation antiepileptic drugs (gabapentin (GBP), lacosamide (LCM), levetiracetam (LEV), pregabalin (PGB) and retigabine (RTG)) in the 6-Hz corneal stimulation-induced seizure model in adult male albino Swiss mice. The anticonvulsant effects of 10 various two-drug combinations of antiepileptic drugs were evaluated with type I isobolographic analysis associated with graphical presentation of polygonogram to visualize the types of interactions. Isobolographic analysis revealed that 7 two-drug combinations of LEV+RTG, LEV+LCM, GBP+RTG, PGB+LEV, GBP+LEV, PGB+RTG, PGB+LCM were synergistic in the 6-Hz corneal stimulation-induced seizure model in mice. The additive interaction was observed for the combinations of GBP+LCM, GBP+PGB, and RTG+LCM in this seizure model in mice. The most beneficial combination, offering the highest level of synergistic suppression of seizures in mice was that of LEV+RTG, whereas the most additive combination that protected the animals from seizures was that reporting additivity for RTG+LCM. The strength of interaction for two-drug combinations can be arranged from the synergistic to the additive, as follows: LEV+RTG > LEV+LCM > GBP+RTG > PGB+LEV > GBP+LEV > PGB+RTG > PGB+LCM > GBP+LCM > GBP+PGB > RTG+LCM.
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Affiliation(s)
- Jarogniew J. Luszczki
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
- Isobolographic Analysis Laboratory, Institute of Rural Health, Lublin, Poland
- * E-mail: ,
| | - Anna Panasiuk
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
- Department of Anesthesiology and Intensive Care, Medical University of Lublin, Lublin, Poland
| | - Mirosław Zagaja
- Isobolographic Analysis Laboratory, Institute of Rural Health, Lublin, Poland
| | | | - Hubert Bojar
- Department of Toxicology and Food Safety, Institute of Rural Health, Lublin, Poland
| | - Zbigniew Plewa
- Department of General, Oncological and Minimally Invasive Surgery, 1st Military Clinical Hospital, Lublin, Poland
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The Endocannabinoid System and Synthetic Cannabinoids in Preclinical Models of Seizure and Epilepsy. J Clin Neurophysiol 2020; 37:15-27. [PMID: 31895186 DOI: 10.1097/wnp.0000000000000633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Cannabinoids are compounds that are structurally and/or functionally related to the primary psychoactive constituent of Cannabis sativa, [INCREMENT]-tetrahydrocannabinol (THC). Cannabinoids can be divided into three broad categories: endogenous cannabinoids, plant-derived cannabinoids, and synthetic cannabinoids (SCs). Recently, there has been an unprecedented surge of interest into the pharmacological and medicinal properties of cannabinoids for the treatment of epilepsies. This surge has been stimulated by an ongoing shift in societal opinions about cannabinoid-based medicines and evidence that cannabidiol, a nonintoxicating plant cannabinoid, has demonstrable anticonvulsant activity in children with treatment-refractory epilepsy. The major receptors of the endogenous cannabinoid system (ECS)-the type 1 and 2 cannabinoid receptors (CB1R, CB2R)-have critical roles in the modulation of neurotransmitter release and inflammation, respectively; so, it is not surprising therefore that the ECS is being considered as a target for the treatment of epilepsy. SCs were developed as potential new drug candidates and tool compounds for studying the ECS. Beyond the plant cannabinoids, an extensive research effort is underway to determine whether SCs that directly target CB1R, CB2R, or the enzymes that breakdown endogenous cannabinoids have anticonvulsant effects in preclinical rodent models of epilepsy and seizure. This research demonstrates that many SCs do reduce seizure severity in rodent models and may have both positive and negative pharmacodynamic and pharmacokinetic interactions with clinically used antiepilepsy drugs. Here, we provide a comprehensive review of the preclinical evidence for and against SC modulation of seizure and discuss the important questions that need to be addressed in future studies.
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Miziak B, Walczak A, Szponar J, Pluta R, Czuczwar SJ. Drug-drug interactions between antiepileptics and cannabinoids. Expert Opin Drug Metab Toxicol 2019; 15:407-415. [DOI: 10.1080/17425255.2019.1605355] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Barbara Miziak
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | - Aleksandra Walczak
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | - Jarosław Szponar
- Toxicology Clinic, Medical University of Lublin, Lublin, Poland
- Clinical Department of Toxicology and Cardiology, Stefan Wyszyński Regional Specialist Hospital, Lublin, Poland
| | - Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warszawa, Poland
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Levetiracetam combined with ACEA, highly selective cannabinoid CB1 receptor agonist changes neurogenesis in mouse brain. Neurosci Lett 2018; 696:79-86. [PMID: 30552944 DOI: 10.1016/j.neulet.2018.12.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 11/13/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022]
Abstract
The aim of the study was to evaluate the impact of second generation antiepileptic drug levetiracetam (LEV) with arachidonyl-2'-chloroethylamide (ACEA) on proliferating neural precursor cells in mouse brain. Additionally, we established the relationship between treatment with ACEA in combination with LEV and hippocampal neurogenesis in mouse brain. All experiments were performed on male CB57/BL mice injected i.p. with LEV (10 mg/kg), ACEA (10 mg/kg) and PMSF (30 mg/kg) for 10 days. Experiments were provided in two stages: stage 1- an acute response of proliferating neural precursor cells to ACEA and LEV administration (Ki-67 staining), stage 2 - a long term response to ACEA and LEV administration (BrDU, NeuN, GFAP staining). Results indicate that ACEA + PMSF and ACEA + PMSF + LEV significantly increased the total number of Ki-67 positive cells comparing to the control group. PMSF and LEV administered alone and in combination had no significant impact on cell proliferation compared to the control group. Results from neurogenesis study indicated that ACEA + PMSF administered alone and in combination with LEV increased the total number of BrDU cells compared to the control group, although LEV on its own decreased the number of BrDU cells. Moreover, the combination of ACEA + PMSF + LEV significantly increased the total number of newborn neurons compared to the control group. In turn, LEV significantly decreased the process of neurogenesis. Astrocytes were considerably reduced in all treated groups as compare to the control mice. These data provide substantial evidence that LEV administered chronically decreases the proliferation and differentiation of newly born cells while combination of LEV + ACEA significantly increases the level of newborn neurons in the dentate subgranular zone.
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Sirin DY, Karaarslan N. Evaluation of the effects of pregabalin on chondrocyte proliferation and CHAD, HIF-1α, and COL2A1 gene expression. Arch Med Sci 2018; 14:1340-1347. [PMID: 30393488 PMCID: PMC6209709 DOI: 10.5114/aoms.2018.73134] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 01/03/2018] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION The aim of the present study is to investigate the effects of pregabalin (PGB) on chondrocyte proliferation and collagen type II (COL2A1), hypoxia-inducible factor 1-α (HIF-1α), and chondroadherin (CHAD) gene expression in osteoarthritic chondrocytes. MATERIAL AND METHODS Standard primary chondrocyte cultures were prepared using osteochondral tissues that were surgically obtained from 6 patients with gonarthrosis. Cell morphology was evaluated using an inverted microscope, and cell death and proliferation were determined through MTT analysis, which was confirmed by AO/PI staining and statistically evaluated. The expression levels of CHAD, COL2A1, and HIF-1α genes were assessed using gene-specific TaqMan Gene Expression Assays. RESULTS MTT analyses showed that PGB administration did not have a negative or toxic effect on cell viability and proliferation in cultured chondrocytes (p < 0.001), but in our morphological evaluation extracellular matrix development was observed to be weaker in cultures treated with PGB. After 24 h of treatment, COL2A1, HIF-1α, and CHAD gene expression decreased in the groups to which PGB was applied compared to gene expression before the experiment (at 0 h); at 48 h, CHAD and HIF-1α expression increased to the same level as the control group, but the expression of COL2A1 continued to decrease. CONCLUSIONS Further studies need to be conducted with more participants to prove that there is a negative correlation between extracellular matrix formation and PGB administration. Our preliminary data show that even at low doses and over short-term administration, PGB may affect chondrocyte cells at the gene-expression level.
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Affiliation(s)
- Duygu Yasar Sirin
- Department of Molecular Biology and Genetics, Faculty of Arts and Sciences, Namik Kemal University, Tekirdag, Turkey
| | - Numan Karaarslan
- Department of Neurosurgery, School of Medicine, Namik Kemal University, Tekirdag, Turkey
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Combination of phenobarbital with phenytoin and pregabalin produces synergy in the mouse tonic-clonic seizure model: An isobolographic analysis. Epilepsy Res 2018; 145:116-122. [PMID: 29940514 DOI: 10.1016/j.eplepsyres.2018.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 06/03/2018] [Accepted: 06/09/2018] [Indexed: 01/13/2023]
Abstract
AIMS Despite many antiepileptic drugs (AEDs) are available to treat epilepsy, there is still about 30% of epilepsy patients inadequately treated with these AEDs. For these patients, polytherapy with two or three AEDs to fully control their seizure attacks is recommended. Unfortunately, polytherapy is always associated with drug interactions, whose nature may be beneficial, neutral or unfavorable. To determine a type of interaction for the combination of three AEDs (i.e., phenobarbital [PB], phenytoin [PHT] and pregabalin [PGB]) at the fixed-ratio of 1:1:1, we used a model of tonic-clonic seizures in male albino Swiss mice. MATERIALS AND METHOD Tonic-clonic seizures in mice were evoked by a current (sine-wave, 25 mA, 500 V, 0.2 s stimulus duration) delivered via auricular electrodes. The anticonvulsant effects of the three-drug combination (PB, PHT and PGB) in terms of suppression of tonic-clonic seizures in mice were assessed with type I isobolographic analysis. Potential acute side effects for the mixture of PB, PHT and PGB along with total brain concentrations of the AEDs were determined to confirm pharmacodynamic nature of observed interaction. RESULTS The three-drug combination of PB, PHT and PGB (at the fixed-ratio of 1:1:1) exerted synergistic interaction (at P < 0.01) in the mouse model of tonic-clonic seizures. The combination of PB, PHT and PGB did not produce any side effects in experimental animals, when measuring long-term memory, muscular strength and motor coordination. The measurement of total brain concentrations of PB, PHT and PGB was conducted to confirm that none of the three AEDs significantly influenced total brain concentrations (pharmacokinetic profiles) of the other co-administered AEDs in mice. CONCLUSIONS The synergistic pharmacodynamic interaction for the combination of PB, PHT and PGB observed in this preclinical study can be translated into clinical settings and this favorable AED combination is worthy of being recommended to some patients with refractory epilepsy.
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Luszczki JJ, Patrzylas P, Zagaja M, Andres-Mach M, Zaluska K, Kondrat-Wrobel MW, Szpringer M, Chmielewski J, Florek-Luszczki M. Effects of arachidonyl-2'-chloroethylamide (ACEA) on the protective action of various antiepileptic drugs in the 6-Hz corneal stimulation model in mice. PLoS One 2017; 12:e0183873. [PMID: 28859122 PMCID: PMC5578658 DOI: 10.1371/journal.pone.0183873] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/12/2017] [Indexed: 12/18/2022] Open
Abstract
Accumulating evidence indicates that cannabinoid CB1 receptor ligands play a pivotal role in seizures, not only in preclinical studies on animals, but also in clinical settings. This study was aimed at characterizing the influence of arachidonyl-2'-chloroethylamide (ACEA-a selective cannabinoid CB1 receptor agonist) co-administered with phenylmethylsulfonyl fluoride (PMSF) on the anticonvulsant potency of various antiepileptic drugs (clobazam, lacosamide, levetiracetam, phenobarbital, tiagabine and valproate) in the 6-Hz corneal stimulation model. Psychomotor seizures in male albino Swiss mice were evoked by a current (32 mA, 6 Hz, 3 s stimulus duration) delivered via corneal electrodes. Potential adverse effects produced by the antiepileptic drugs in combination with ACEA+PMSF were assessed using the chimney test (motor performance), passive avoidance task (remembering and acquisition of learning), and grip-strength test (muscular strength). Brain concentrations of antiepileptic drugs were measured by HPLC to exclude any pharmacokinetic contribution to the observed effect. ACEA (5 mg/kg, i.p.) + PMSF (30 mg/kg, i.p.) significantly potentiated the anticonvulsant potency of levetiracetam (P<0.05), but not that of clobazam, lacosamide, phenobarbital, tiagabine or valproate in the 6-Hz corneal stimulation model. Moreover, ACEA+PMSF did not significantly affect total brain concentrations of levetiracetam in mice. No behavioral side effects were observed in animals receiving combinations of the studied antiepileptic drugs with ACEA+PMSF. In conclusion, the combined administration of ACEA+PMSF with levetiracetam is associated with beneficial anticonvulsant pharmacodynamic interaction in the 6-Hz corneal stimulation model. The selective activation of cannabinoid CB1 receptor-mediated neurotransmission in the brain may enhance levetiracetam-related suppression of seizures in epilepsy patients, contributing to the efficacious treatment of epilepsy in future.
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Affiliation(s)
- Jarogniew J. Luszczki
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
- Isobolographic Analysis Laboratory, Institute of Rural Health, Lublin, Poland
| | - Pawel Patrzylas
- Isobolographic Analysis Laboratory, Institute of Rural Health, Lublin, Poland
- Department of Plant Physiology and Biotechnology, The John Paul II Catholic University of Lublin, Lublin, Poland
| | - Miroslaw Zagaja
- Isobolographic Analysis Laboratory, Institute of Rural Health, Lublin, Poland
| | - Marta Andres-Mach
- Isobolographic Analysis Laboratory, Institute of Rural Health, Lublin, Poland
| | - Katarzyna Zaluska
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | | | - Monika Szpringer
- Faculty of Medicine and Health Sciences, The Jan Kochanowski University in Kielce, Kielce, Poland
| | - Jaroslaw Chmielewski
- Institute of Environmental Protection—National Research Institute, Warszawa, Poland
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A Long-Term Treatment with Arachidonyl-2'-Chloroethylamide Combined with Valproate Increases Neurogenesis in a Mouse Pilocarpine Model of Epilepsy. Int J Mol Sci 2017; 18:ijms18050900. [PMID: 28441341 PMCID: PMC5454813 DOI: 10.3390/ijms18050900] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 04/12/2017] [Accepted: 04/19/2017] [Indexed: 01/06/2023] Open
Abstract
Rational polytherapy in the treatment of refractory epilepsy has been the main therapeutic modality for several years. In treatment with two or more antiepileptic drugs (AEDs), it is of particular importance that AEDs be selected based on their high anticonvulsant properties, minimal side effects, and impact on the formation of new neurons. The aim of the study was to conduct an in vivo evaluation of the relationship between treatments with synthetic cannabinoid arachidonyl-2′-chloroethylamide (ACEA) alone or in combination with valproic acid (VPA) and hippocampal neurogenesis in a mouse pilocarpine model of epilepsy. All studies were performed on adolescent male CB57/BL mice with using the following drugs: VPA (10 mg/kg), ACEA (10 mg/kg), phenylmethylsulfonyl fluoride (PMSF—a substance protecting ACEA against degradation by fatty acid hydrolase, 30 mg/kg), pilocarpine (PILO, a single dose of 290 mg/kg) and methylscopolamine (30 min before PILO to stop peripheral cholinergic effects of pilocarpine, 1 mg/kg). We evaluated the process of neurogenesis after a 10-day treatment with ACEA and VPA, alone and in combination. We observed a decrease of neurogenesis in the PILO control group as compared to the healthy control mice. Furthermore, ACEA + PMSF alone and in combination with VPA significantly increased neurogenesis compared to the PILO control group. In contrast, VPA 10-day treatment had no impact on the level of neurons in comparison to the PILO control group. The combination of ACEA, PMSF and VPA considerably stimulated the process of creating new cells, particularly neurons, while chronic administration of VPA itself had no influence on neurogenesis in the mouse pilocarpine model of epilepsy. The obtained results enabled an in vivo evaluation of neurogenesis after treatment with antiepileptic drugs in an experimental model of epilepsy.
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Ulugol A, Topuz RD, Gunduz O, Kizilay G, Karadag HC. Changes in nociceptin/orphanin FQ levels in rat brain regions after acute and chronic cannabinoid treatment in conjunction with the development of antinociceptive tolerance. Fundam Clin Pharmacol 2016; 30:537-548. [PMID: 27371029 DOI: 10.1111/fcp.12215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 06/06/2016] [Accepted: 06/29/2016] [Indexed: 01/30/2023]
Abstract
It has been indicated that acute and chronic morphine administrations enhance nociceptin/orphanin FQ (N/OFQ) levels in the brain, which might play role in the development of tolerance to the antinociceptive effect of morphine. Accordingly, N/OFQ receptor (NOP) antagonists have been shown to prevent the development of antinociceptive tolerance to morphine. Our aim is to observe whether cannabinoids, similarly to opioids, enhance N/OFQ levels in pain-related brain regions and whether antagonism of NOP receptors attenuates the development of tolerance to the antinociceptive effect of cannabinoids. Hot plate and Tail flick tests are used to assess the antinociceptive response in Sprague-Dawley rats. N/OFQ levels are measured in cortex, amygdala, hypothalamus, periaqueductal gray, nucleus raphe magnus and locus coeruleus of rat brains using Western blotting and immunohistochemistry. Within 9 days, animals became completely tolerant to the antinociceptive effect of the cannabinoid agonist WIN 55,212-2 (2, 4, 6 mg/kg, i.p.). Chronic administration of JTC-801, a NOP receptor antagonist, at a dose that exerted no effect on its own (1 mg/kg, i.p.), attenuated development of tolerance to the antinociceptive effect of WIN 55,212-2 (4 mg/kg, i.p.). Western blotting and immunohistochemistry results showed that N/OFQ levels significantly increased in amygdala, periaqueductal gray, nucleus raphe magnus and locus coeruleus of rat brains when WIN 55,212-2 was combined with JTC-801. We hypothesize that, similar to opioids, chronic cannabinoid + NOP antagonist administration may enhance N/OFQ levels and NOP receptor antagonism prevents development of tolerance to cannabinoid antinociception.
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Affiliation(s)
- Ahmet Ulugol
- Department of Medical Pharmacology, Faculty of Medicine, Trakya University, 22030, Edirne, Turkey
| | - Ruhan D Topuz
- Department of Medical Pharmacology, Faculty of Medicine, Trakya University, 22030, Edirne, Turkey
| | - Ozgur Gunduz
- Department of Medical Pharmacology, Faculty of Medicine, Trakya University, 22030, Edirne, Turkey
| | - Gulnur Kizilay
- Department of Histology and Embryology, Faculty of Medicine, Trakya University, 22030, Edirne, Turkey
| | - Hakan C Karadag
- Department of Medical Pharmacology, Faculty of Medicine, Trakya University, 22030, Edirne, Turkey
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Fine Mapping of a Dravet Syndrome Modifier Locus on Mouse Chromosome 5 and Candidate Gene Analysis by RNA-Seq. PLoS Genet 2016; 12:e1006398. [PMID: 27768696 PMCID: PMC5074504 DOI: 10.1371/journal.pgen.1006398] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 10/03/2016] [Indexed: 12/19/2022] Open
Abstract
A substantial number of mutations have been identified in voltage-gated sodium channel genes that result in various forms of human epilepsy. SCN1A mutations result in a spectrum of severity ranging from mild febrile seizures to Dravet syndrome, an infant-onset epileptic encephalopathy. Dravet syndrome patients experience multiple seizures types that are often refractory to treatment, developmental delays, and elevated risk for SUDEP. The same sodium channel mutation can produce epilepsy phenotypes of varying clinical severity. This suggests that other factors, including genetic, modify the primary mutation and change disease severity. Mouse models provide a useful tool in studying the genetic basis of epilepsy. The mouse strain background can alter phenotype severity, supporting a contribution of genetic modifiers in epilepsy. The Scn1a+/- mouse model has a strain-dependent epilepsy phenotype. Scn1a+/- mice on the 129S6/SvEvTac (129) strain have a normal phenotype and lifespan, while [129xC57BL/6J]F1-Scn1a+/- mice experience spontaneous seizures, hyperthermia-induced seizures and high rates of premature death. We hypothesize the phenotypic differences are due to strain-specific genetic modifiers that influence expressivity of the Scn1a+/- phenotype. Low resolution mapping of Scn1a+/- identified several Dravet syndrome modifier (Dsm) loci responsible for the strain-dependent difference in survival. One locus of interest, Dsm1 located on chromosome 5, was fine mapped to a 9 Mb region using interval specific congenics. RNA-Seq was then utilized to identify candidate modifier genes within this narrowed region. Three genes with significant total gene expression differences between 129S6/SvEvTac and [129xC57BL/6J]F1 were identified, including the GABAA receptor subunit, Gabra2. Further analysis of Gabra2 demonstrated allele-specific expression. Pharmological manipulation by clobazam, a common anticonvulsant with preferential affinity for the GABRA2 receptor, revealed dose-dependent protection against hyperthermia-induced seizures in Scn1a+/- mice. These findings support Gabra2 as a genetic modifier of the Scn1a+/- mouse model of Dravet syndrome. Epilepsy is a neurological disorder affecting approximately 3 million Americans and 1% of the worldwide population. Approximately 70% of patients diagnosed with epilepsy have a genetic basis for their disease. The same genetic mutation can result in epilepsy with varying clinical severity in some individuals. This suggests that additional factors modify the effect of the primary mutation, resulting in the differences observed. Mouse models of epilepsy also exhibit variable severity depending on the inbred strain background. This is a useful model system that enables us to determine other genetic factors that influence phenotype presentation. This study investigates a mouse model of Dravet syndrome. Similar to Dravet syndrome patients, the mice experience a variety of seizure types and have increased risk for premature death. Interestingly, the Dravet syndrome phenotype is completely masked on one mouse strain background. Through a series of genetic and pharmacological techniques we were able to identify a gene that is likely responsible for the strain-dependent phenotype difference of Dravet mice. Identifying genes that modify diseases can help predict patient outcomes and suggest new therapies for the treatment of epilepsy.
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The use of cannabis as an antiepileptic treatment in Mexico: A review, bioethical analysis, discussion and position of the Hospital General de México Epilepsy Clinic. REVISTA MÉDICA DEL HOSPITAL GENERAL DE MÉXICO 2016. [DOI: 10.1016/j.hgmx.2016.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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