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Socała K, Jakubiec M, Abram M, Mlost J, Starowicz K, Kamiński RM, Ciepiela K, Andres-Mach M, Zagaja M, Metcalf CS, Zawadzki P, Wlaź P, Kamiński K. TRPV1 channel in the pathophysiology of epilepsy and its potential as a molecular target for the development of new antiseizure drug candidates. Prog Neurobiol 2024; 240:102634. [PMID: 38834133 DOI: 10.1016/j.pneurobio.2024.102634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 04/26/2024] [Accepted: 05/28/2024] [Indexed: 06/06/2024]
Abstract
Identification of transient receptor potential cation channel, subfamily V member 1 (TRPV1), also known as capsaicin receptor, in 1997 was a milestone achievement in the research on temperature sensation and pain signalling. Very soon after it became evident that TRPV1 is implicated in a wide array of physiological processes in different peripheral tissues, as well as in the central nervous system, and thereby could be involved in the pathophysiology of numerous diseases. Increasing evidence suggests that modulation of TRPV1 may also affect seizure susceptibility and epilepsy. This channel is localized in brain regions associated with seizures and epilepsy, and its overexpression was found both in animal models of seizures and in brain samples from epileptic patients. Moreover, modulation of TRPV1 on non-neuronal cells (microglia, astrocytes, and/or peripheral immune cells) may have an impact on the neuroinflammatory processes that play a role in epilepsy and epileptogenesis. In this paper, we provide a comprehensive and critical overview of currently available data on TRPV1 as a possible molecular target for epilepsy management, trying to identify research gaps and future directions. Overall, several converging lines of evidence implicate TRPV1 channel as a potentially attractive target in epilepsy research but more studies are needed to exploit the possible role of TRPV1 in seizures/epilepsy and to evaluate the value of TRPV1 ligands as candidates for new antiseizure drugs.
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Affiliation(s)
- Katarzyna Socała
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, Lublin PL 20-033, Poland.
| | - Marcin Jakubiec
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
| | - Michał Abram
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
| | - Jakub Mlost
- Department of Neurochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, Cracow PL 31-343, Poland
| | - Katarzyna Starowicz
- Department of Neurochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, Cracow PL 31-343, Poland
| | - Rafał M Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
| | - Katarzyna Ciepiela
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland; Selvita S.A., Bobrzyńskiego 14, Cracow PL 30-348, Poland
| | - Marta Andres-Mach
- Department of Experimental Pharmacology, Institute of Rural Health, Jaczewskiego 2, Lublin PL 20-090, Poland
| | - Mirosław Zagaja
- Department of Experimental Pharmacology, Institute of Rural Health, Jaczewskiego 2, Lublin PL 20-090, Poland
| | - Cameron S Metcalf
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA
| | - Przemysław Zawadzki
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
| | - Piotr Wlaź
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, Lublin PL 20-033, Poland
| | - Krzysztof Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
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2
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Hippocampal expression of the cannabinoid receptor type 1 in canine epilepsy. Sci Rep 2023; 13:3138. [PMID: 36823232 PMCID: PMC9950490 DOI: 10.1038/s41598-023-29868-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 02/11/2023] [Indexed: 02/25/2023] Open
Abstract
Canine drug-resistant epilepsy is a prevailing issue in veterinary neurology. Alternative or additional treatment with cannabinoids is showing promising results in seizure management. A crucial component of the endocannabinoid system, cannabinoid receptor type 1 (CB1R), is heavily involved in the control of neurotransmitter release. Knowledge of its distribution in the epileptic brain would serve a better understanding of disease pathology and application of cannabinoids in dogs with epilepsy. CB1R distribution was assessed in sub-regions of hippocampus of dogs with idiopathic epilepsy, structural epilepsy and without cerebral pathology. In dogs with idiopathic epilepsy, significantly decreased CB1R expression compared to control animals was observed in CA1. In dogs with structural epilepsy, a significant increase in CB1R signal intensity in comparison to controls was observed. CB1R expression was higher in the structural group as compared to the idiopathic. Double immunofluorescence showed co-localization between CB1R and an astrocytic marker in about 50% of cells, regardless of the diagnosis. In summary, CB1R expression in canine hippocampus undergoes modification by the epileptic process and the direction of this change depends on the etiology of the disease. The distinct disease-associated CB1R expression needs to be considered in new treatment development for dogs with epilepsy.
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Neuroplastic alterations in cannabinoid receptors type 1 (CB1) in animal models of epileptic seizures. Neurosci Biobehav Rev 2022; 137:104675. [PMID: 35460705 DOI: 10.1016/j.neubiorev.2022.104675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/16/2022] [Accepted: 04/17/2022] [Indexed: 01/01/2023]
Abstract
Currently, there is an urgent need to better comprehend neuroplastic alterations in cannabinoid receptors type 1 (CB1) and to understand the biological meaning of these alterations in epileptic disorders. The present study reviewed neuroplastic changes in CB1 distribution, expression, and functionality in animal models of epileptic seizures. Neuroplastic alterations in CB1 were consistently observed in chemical, genetic, electrical, and febrile seizure models. Most studies assessed changes in hippocampal and cortical CB1, while thalamic, hypothalamic, and brainstem nuclei were rarely investigated. Additionally, the relationship between CB1 alteration and the control of brain excitability through modulation of specific neuronal networks, such as striatonigral, nigrotectal and thalamocortical pathways, and inhibitory projections to hippocampal pyramidal neurons, were all presented and discussed in the present review. Neuroplastic alterations in CB1 detected in animal models of epilepsy may reflect two different scenarios: (1) endogenous adaptations aimed to control neuronal hyperexcitability in epilepsy or (2) pathological alterations that facilitate neuronal hyperexcitability. Additionally, a better comprehension of neuroplastic and functional alterations in CB1 can improve pharmacological therapies for epilepsies and their comorbidities.
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4
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Khaksar S, Salimi M, Zeinoddini H, Naderi N. The Role of the Possible Receptors and Intracellular Pathways in Protective Effect of Exogenous Anandamide in Kindling Model of Epilepsy. Neurochem Res 2022; 47:1226-1242. [PMID: 35112235 DOI: 10.1007/s11064-021-03517-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 12/01/2021] [Accepted: 12/24/2021] [Indexed: 11/24/2022]
Abstract
In this research, the involvement of CB1 and TRPV1 receptors in the possible protective effects of anandamide were investigated in the kindling model of epilepsy. The basolateral amygdala of the rat brain was chosen to put stimulating electrodes. Semi-rapid kindling was induced by a repetitive sub-threshold stimulation for 5-9 consecutive days. There were seven groups, six of which were kindled and used for drug testing by intracerebroventricular (i.c.v.) microinjection. (i) Sham, (ii) control group received vehicles, (iii) anandamide (AEA; 100 ng/rat), (iv) capsazepine (TRPV1 antagonist; 100 ng/rat), (v) AM251 (CB1 antagonist; 100 ng/rat), (vi) AM251 + anandamide, and (vii) capsazepine + anandamide. The after-discharge duration, seizure duration, and stage five duration were measured in rats. Moreover, the expressions of the extracellular signal-regulated kinase (ERK) and the cAMP responsive element binding (CREB) proteins in the hippocampus were also studied. The anandamide-treated group showed a significant decrease in seizure scores, while no change was shown in seizure scores in the capsazepine- and AM251-treated groups compared with the control group. Co-administrations of either capsazepine + AEA or AM251 + AEA attenuated the protective effect of AEA against seizure. Furthermore, the group received AEA showed a decrease in the expressions of CREB and p-CREB possibly through the activation of the CB1 and TRPV1 receptors. Activation of CB1 and TRPV1 receptors might be involved in AEA anticonvulsant effect in kindling model of epilepsy. This effect could be due to suppression of CREB phosphorylation in hippocampal neurons.
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Affiliation(s)
- Sepideh Khaksar
- Department of Plant Sciences, Biological Sciences, Alzahra University, Tehran, Iran
| | - Mona Salimi
- Department of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, Iran
| | - Hadi Zeinoddini
- Department of Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, No. 2660, Vali-e-Asr Ave, 1996835113, Tehran, Iran
| | - Nima Naderi
- Department of Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, No. 2660, Vali-e-Asr Ave, 1996835113, Tehran, Iran. .,Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Sugaya Y, Kano M. Endocannabinoid-Mediated Control of Neural Circuit Excitability and Epileptic Seizures. Front Neural Circuits 2022; 15:781113. [PMID: 35046779 PMCID: PMC8762319 DOI: 10.3389/fncir.2021.781113] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/29/2021] [Indexed: 01/11/2023] Open
Abstract
Research on endocannabinoid signaling has greatly advanced our understanding of how the excitability of neural circuits is controlled in health and disease. In general, endocannabinoid signaling at excitatory synapses suppresses excitability by inhibiting glutamate release, while that at inhibitory synapses promotes excitability by inhibiting GABA release, although there are some exceptions in genetically epileptic animal models. In the epileptic brain, the physiological distributions of endocannabinoid signaling molecules are disrupted during epileptogenesis, contributing to the occurrence of spontaneous seizures. However, it is still unknown how endocannabinoid signaling changes during seizures and how the redistribution of endocannabinoid signaling molecules proceeds during epileptogenesis. Recent development of cannabinoid sensors has enabled us to investigate endocannabinoid signaling in much greater spatial and temporal details than before. Application of cannabinoid sensors to epilepsy research has elucidated activity-dependent changes in endocannabinoid signaling during seizures. Furthermore, recent endocannabinoid research has paved the way for the clinical use of cannabidiol for the treatment of refractory epilepsy, such as Dravet syndrome, Lennox-Gastaut syndrome and tuberous sclerosis complex. Cannabidiol significantly reduces seizures and is considered to have comparable tolerability to conventional antiepileptic drugs. In this article, we introduce recent advances in research on the roles of endocannabinoid signaling in epileptic seizures and discuss future directions.
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Affiliation(s)
- Yuki Sugaya
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Tokyo, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Tokyo, Japan
- *Correspondence: Masanobu Kano,
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6
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Epps SA. Commonalities for comorbidity: Overlapping features of the endocannabinoid system in depression and epilepsy. Front Psychiatry 2022; 13:1041460. [PMID: 36339877 PMCID: PMC9626804 DOI: 10.3389/fpsyt.2022.1041460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 09/29/2022] [Indexed: 11/13/2022] Open
Abstract
A wealth of clinical and pre-clinical data supports a bidirectional comorbidity between depression and epilepsy. This suggests commonalities in underlying mechanisms that may serve as targets for more effective treatment strategies. Unfortunately, many patients with this comorbidity are highly refractory to current treatment strategies, while others experience a worsening of one arm of the comorbidity when treating the other arm. This highlights the need for novel pharmaceutical targets that may provide safe and effective relief for both depression and epilepsy symptoms. The endocannabinoid system (ECS) of the brain has become an area of intense interest for possible roles in depression and epilepsy. Several existing literature reviews have provided in-depth analysis of the involvement of various aspects of the ECS in depression or epilepsy separately, while others have addressed the effectiveness of different treatment strategies targeting the ECS in either condition individually. However, there is not currently a review that considers the ECS when both conditions are comorbid. This mini-review will address areas of common overlap between the ECS in depression and in epilepsy, such as commonalities in endocannabinoids themselves, their receptors, and degradative enzymes. These areas of overlap will be discussed alongside their implications for treatment of this challenging comorbidity.
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Affiliation(s)
- S Alisha Epps
- Department of Psychology, Whitworth University, Spokane, WA, United States
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7
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Wang X, Liao Q, Chen H, Gong G, Siu SWI, Chen Q, Kam H, Ung COL, Cheung KK, Rádis-Baptista G, Wong CTT, Lee SMY. Toxic Peptide From Palythoa caribaeorum Acting on the TRPV1 Channel Prevents Pentylenetetrazol-Induced Epilepsy in Zebrafish Larvae. Front Pharmacol 2021; 12:763089. [PMID: 34925021 PMCID: PMC8672801 DOI: 10.3389/fphar.2021.763089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/08/2021] [Indexed: 11/25/2022] Open
Abstract
PcActx peptide, identified from the transcriptome of zoantharian Palythoa caribaeorum, was clustered into the phylogeny of analgesic polypeptides from sea anemone Heteractis crispa (known as APHC peptides). APHC peptides were considered as inhibitors of transient receptor potential cation channel subfamily V member 1 (TRPV1). TRPV1 is a calcium-permeable channel expressed in epileptic brain areas, serving as a potential target for preventing epileptic seizures. Through in silico and in vitro analysis, PcActx peptide was shown to be a potential TRPV1 channel blocker. In vivo studies showed that the linear and oxidized PcActx peptides caused concentration-dependent increases in mortality of zebrafish larvae. However, monotreatment with PcActx peptides below the maximum tolerated doses (MTD) did not affect locomotor behavior. Moreover, PcActx peptides (both linear and oxidized forms) could effectively reverse pentylenetetrazol (PTZ)-induced seizure-related behavior in zebrafish larvae and prevent overexpression of c-fos and npas4a at the mRNA level. The excessive production of ROS induced by PTZ was markedly attenuated by both linear and oxidized PcActx peptides. It was also verified that the oxidized PcActx peptide was more effective than the linear one. In particular, oxidized PcActx peptide notably modulated the mRNA expression of genes involved in calcium signaling and γ-aminobutyric acid (GABA)ergic-glutamatergic signaling, including calb1, calb2, gabra1, grm1, gria1b, grin2b, gat1, slc1a2b, gad1b, and glsa. Taken together, PcActx peptide, as a novel neuroactive peptide, exhibits prominent anti-epileptic activity, probably through modulating calcium signaling and GABAergic-glutamatergic signaling, and is a promising candidate for epilepsy management.
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Affiliation(s)
- Xiufen Wang
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Qiwen Liao
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China.,School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, China
| | - Hanbin Chen
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Guiyi Gong
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Shirley Weng In Siu
- Department of Computer and Information Science, Faculty of Science and Technology, University of Macau, Macau, China
| | - Qian Chen
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Hiotong Kam
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Carolina Oi Lam Ung
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Kwok-Kuen Cheung
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, China
| | - Gandhi Rádis-Baptista
- Laboratory of Biochemistry and Biotechnology, Institute for Marine Sciences, Federal University of Ceará, Fortaleza, Brazil
| | - Clarence Tsun Ting Wong
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
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8
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Asth L, Iglesias LP, De Oliveira AC, Moraes MFD, Moreira FA. Exploiting cannabinoid and vanilloid mechanisms for epilepsy treatment. Epilepsy Behav 2021; 121:106832. [PMID: 31839498 DOI: 10.1016/j.yebeh.2019.106832] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 11/25/2019] [Accepted: 11/25/2019] [Indexed: 12/28/2022]
Abstract
This review focuses on the possible roles of phytocannabinoids, synthetic cannabinoids, endocannabinoids, and "transient receptor potential cation channel, subfamily V, member 1" (TRPV1) channel blockers in epilepsy treatment. The phytocannabinoids are compounds produced by the herb Cannabis sativa, from which Δ9-tetrahydrocannabinol (Δ9-THC) is the main active compound. The therapeutic applications of Δ9-THC are limited, whereas cannabidiol (CBD), another phytocannabinoid, induces antiepileptic effects in experimental animals and in patients with refractory epilepsies. Synthetic CB1 agonists induce mixed effects, which hamper their therapeutic applications. A more promising strategy focuses on compounds that increase the brain levels of anandamide, an endocannabinoid produced on-demand to counteract hyperexcitability. Thus, anandamide hydrolysis inhibitors might represent a future class of antiepileptic drugs. Finally, compounds that block the TRPV1 ("vanilloid") channel, a possible anandamide target in the brain, have also been investigated. In conclusion, the therapeutic use of phytocannabinoids (CBD) is already in practice, although its mechanisms of action remain unclear. Endocannabinoid and TRPV1 mechanisms warrant further basic studies to support their potential clinical applications. This article is part of the Special Issue "NEWroscience 2018".
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Affiliation(s)
- Laila Asth
- Graduate School in Physiology and Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil
| | - Lia P Iglesias
- Graduate School in Neurosciences, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil
| | - Antônio C De Oliveira
- Graduate School in Physiology and Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil; Graduate School in Neurosciences, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil; Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil
| | - Marcio F D Moraes
- Graduate School in Physiology and Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil; Graduate School in Neurosciences, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil; Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil
| | - Fabrício A Moreira
- Graduate School in Physiology and Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil; Graduate School in Neurosciences, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil; Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Brazil.
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9
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Cabral-Pereira G, Sánchez-Benito D, Díaz-Rodríguez SM, Gonçalves J, Sancho C, Castellano O, Muñoz LJ, López DE, Gómez-Nieto R. Behavioral and Molecular Effects Induced by Cannabidiol and Valproate Administration in the GASH/Sal Model of Acute Audiogenic Seizures. Front Behav Neurosci 2021; 14:612624. [PMID: 33551767 PMCID: PMC7862126 DOI: 10.3389/fnbeh.2020.612624] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/09/2020] [Indexed: 11/13/2022] Open
Abstract
Despite evidence that supports cannabidiol (CBD) as an anticonvulsant agent, there remains controversy over the antiseizure efficacy, possible adverse effects, and synergistic interactions with classic antiepileptics such as valproate (VPA). The genetic audiogenic seizure hamster from the University of Salamanca (GASH/Sal) is a reliable experimental model of generalized tonic–clonic seizures in response to intense sound stimulation. The present study examines the behavioral and molecular effects of acute and chronic intraperitoneal administrations of VPA (300 mg/kg) and CBD (100 mg/kg) on the GASH/Sal audiogenic seizures, as well as the coadministration of both drugs. The GASH/Sal animals were examined prior to and after the corresponding treatment at 45 min, 7 days, and 14 days for seizure severity and neuroethology, open-field behaviors, body weight variations, and various hematological and biochemical parameters. Furthermore, the brain tissue containing the inferior colliculus (so-called epileptogenic nucleus) was processed for reverse transcription–quantitative polymerase chain reaction analysis to determine the treatment effects on the gene expression of neuronal receptors associated with drug actions and ictogenesis. Our results indicated that single dose of VPA helps prevent the animals from getting convulsions, showing complete elimination of seizures, whereas 7 days of chronic VPA treatment had few effects in seizure behaviors. Acute CBD administration showed subtle attenuation of seizure behaviors, increasing seizure latency and decreasing the duration of the convulsion phase, but without entirely seizure abolition. Chronic CBD treatments had no significant effects on sound-induced seizures, although some animals slightly improved seizure severity. Acute and chronic CBD treatments have no significant adverse effects on body weight, hematological parameters, and liver function, although locomotor activity was reduced. The combination of VPA and CBD did not alter the therapeutic outcome of the VPA monotherapy, showing no apparent synergistic effects. As compared to sham animals, chronic treatments with CBD caused abnormal mRNA expression levels for Trpv1, Adora1, Slc29a1, and Cnr1 genes, whereas no differences in gene expression were found for Htr1a and Sigmar1. Our study shed light on the behavioral and molecular effects of CBD and VPA on the GASH/Sal model and constituted the basis to develop further studies on the pharmacological effects of CBD and its interactions with other anticonvulsants.
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Affiliation(s)
- Giselda Cabral-Pereira
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.,Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain
| | - David Sánchez-Benito
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.,Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain
| | - Sandra M Díaz-Rodríguez
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.,Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain.,Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain
| | - Jaime Gonçalves
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.,Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain.,Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain
| | - Consuelo Sancho
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.,Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain.,Department of Physiology and Pharmacology, Faculty of Medicine, University of Salamanca, Salamanca, Spain
| | - Orlando Castellano
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.,Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain.,Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain
| | - Luis J Muñoz
- Animal Research and Service Center, University of Salamanca, Salamanca, Spain
| | - Dolores E López
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.,Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain.,Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain
| | - Ricardo Gómez-Nieto
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.,Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain.,Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain
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10
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Xue B, Zhang X, Wang Y. Bench to bedside: Multiple facets of cannabinoid control in epilepsy. Neurochem Int 2020; 141:104898. [PMID: 33159980 DOI: 10.1016/j.neuint.2020.104898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 11/27/2022]
Abstract
Epilepsy is a neurological disease recognized as the consequence of excessive neuronal excitability. Endocannabinoid system, the critical regulator of synaptic inhibition in brain, was supposed to be closely involved in epilepsy. Cannabinoid receptors mostly locate on presynaptic terminals of both excitatory and inhibitory neurons, but with characteristic distribution varying in different brain areas and synapses. Endocannabinoids are synthesized in postsynaptic neurons and retrogradely act on presynaptic cannabinoid receptors. Accumulating evidence suggest that the expression of cannabinoid receptors and synthesis or breakdown of endocannabinoids were cell-type specifically altered and spatiotemporally regulated in seizures, and intervention of the expression of cannabinoid receptors or the level of endocannabinoids could affect seizure actions. Further in clinic, cannabidiol as an add-on treatment could reduce seizures in patients with treatment-resistant epilepsy, but the underlying mechanisms are still unclear and independent of the endocannabinoid system. Therefore, we review recent advances from bench to bedside, to address the cannabinoid control on seizures, discuss the existing confusion in current studies and provide directions for further research, which may be clinically important for the design of cannabinoid-based precise therapeutic interventions for epilepsy.
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Affiliation(s)
- Bao Xue
- Institute of Brain Science and Disease, Qingdao University, No. 308, Ningxia Road, Qingdao, 266071, China; School of Basic Medicine, Qingdao University, No. 308, Ningxia Road, Qingdao, 266071, China
| | - Xia Zhang
- Institute of Brain Science and Disease, Qingdao University, No. 308, Ningxia Road, Qingdao, 266071, China
| | - Ying Wang
- Institute of Brain Science and Disease, Qingdao University, No. 308, Ningxia Road, Qingdao, 266071, China.
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11
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Li Y, Wang C, Wang P, Li X, Zhou L. Effects of febrile seizures in mesial temporal lobe epilepsy with hippocampal sclerosis on gene expression using bioinformatical analysis. ACTA EPILEPTOLOGICA 2020. [DOI: 10.1186/s42494-020-00027-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractBackgroundTo investigate the effect of long-term febrile convulsions on gene expression in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and explore the molecular mechanism of MTLE-HS.MethodsMicroarray data of MTLE-HS were obtained from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between MTLE-HS with and without febrile seizure history were screened by the GEO2R software. Pathway enrichment and gene ontology of the DEGs were analyzed using the DAVID online database and FunRich software. Protein–protein interaction (PPI) networks among DEGs were constructed using the STRING database and analyzed by Cytoscape.ResultsA total of 515 DEGs were identified in MTLE-HS samples with a febrile seizure history compared to MTLE-HS samples without febrile seizure, including 25 down-regulated and 490 up-regulated genes. These DEGs were expressed mostly in plasma membrane and synaptic vesicles. The major molecular functions of those genes were voltage-gated ion channel activity, extracellular ligand-gated ion channel activity and calcium ion binding. The DEGs were mainly involved in biological pathways of cell communication signal transduction and transport. Five genes (SNAP25, SLC32A1, SYN1, GRIN1,andGRIA1) were significantly expressed in the MTLE-HS with prolonged febrile seizures.ConclusionThe pathogenesis of MTLE-HS involves multiple genes, and prolonged febrile seizures could cause differential expression of genes. Thus, investigations of those genes may provide a new perspective into the mechanism of MTLE-HS.
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Lourenço DM, Ribeiro-Rodrigues L, Sebastião AM, Diógenes MJ, Xapelli S. Neural Stem Cells and Cannabinoids in the Spotlight as Potential Therapy for Epilepsy. Int J Mol Sci 2020; 21:E7309. [PMID: 33022963 PMCID: PMC7582633 DOI: 10.3390/ijms21197309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 09/28/2020] [Accepted: 09/30/2020] [Indexed: 01/18/2023] Open
Abstract
Epilepsy is one of the most common brain diseases worldwide, having a huge burden in society. The main hallmark of epilepsy is the occurrence of spontaneous recurrent seizures, having a tremendous impact on the lives of the patients and of their relatives. Currently, the therapeutic strategies are mostly based on the use of antiepileptic drugs, and because several types of epilepsies are of unknown origin, a high percentage of patients are resistant to the available pharmacotherapy, continuing to experience seizures overtime. Therefore, the search for new drugs and therapeutic targets is highly important. One key aspect to be targeted is the aberrant adult hippocampal neurogenesis (AHN) derived from Neural Stem Cells (NSCs). Indeed, targeting seizure-induced AHN may reduce recurrent seizures and shed some light on the mechanisms of disease. The endocannabinoid system is a known modulator of AHN, and due to the known endogenous antiepileptic properties, it is an interesting candidate for the generation of new antiepileptic drugs. However, further studies and clinical trials are required to investigate the putative mechanisms by which cannabinoids can be used to treat epilepsy. In this manuscript, we will review how cannabinoid-induced modulation of NSCs may promote neural plasticity and whether these drugs can be used as putative antiepileptic treatment.
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Affiliation(s)
- Diogo M. Lourenço
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Leonor Ribeiro-Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ana M. Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Maria J. Diógenes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Sara Xapelli
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
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13
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Gray RA, Stott CG, Jones NA, Di Marzo V, Whalley BJ. Anticonvulsive Properties of Cannabidiol in a Model of Generalized Seizure Are Transient Receptor Potential Vanilloid 1 Dependent. Cannabis Cannabinoid Res 2020; 5:145-149. [PMID: 32656346 PMCID: PMC7347071 DOI: 10.1089/can.2019.0028] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Introduction: Highly purified cannabidiol (CBD) (approved as Epidiolex® in the United States) has demonstrated efficacy with an acceptable safety profile in patients with Lennox–Gastaut or Dravet syndrome in four randomized controlled trials. CBD possesses affinity for many target classes with functional effects relevant to the pathophysiology of many disease types, including epilepsy. Although the mechanism of action of CBD underlying the reduction of seizures in humans is unknown, transient receptor potential vanilloid 1 (TRPV1) represents a plausible target because (1) CBD activates and then desensitizes TRPV1, (2) TRPV1 is overexpressed in models of temporal lobe epilepsy and patients with epilepsy, (3) and TRPV1 modulates neuronal excitability. Methods: To investigate a potential role of TRPV1 in the anticonvulsive effects of CBD, the effect of CBD on seizure threshold was assessed using a mouse maximal electroshock threshold model of generalized seizure in TRPV1 knockout and wildtype mice. The dose dependence of the CBD effect was determined and compared with that of the positive comparator diazepam and vehicle. Results: At 50 and 100 mg/kg, CBD significantly (p<0.0001) increased seizure threshold in wildtype mice compared with TRPV1 knockout and vehicle controls. This effect was observed only at 100 mg/kg in TRPV1 knockout mice compared with knockout vehicle mice, in which gene deletion partially attenuated the CBD-increased seizure threshold. The effect of high-dose CBD in wildtype mice was nevertheless significantly different from vehicle-treated TRPV1 knockout mice (p<0.0001). Bioanalysis confirmed that genotype-specific differential brain exposure to CBD was not responsible for the observed effect on seizure threshold. Conclusion: These data strongly implicate TRPV1 in the potential mechanisms of action for the anticonvulsive effects of CBD. The partial inhibition of the anticonvulsive effect of high-dose CBD in TRPV1 knockout mice may indicate the involvement of targets other than TRPV1. Further characterization of TRPV1 in the anticonvulsive effect of CBD in validated models of seizure is warranted, as is pharmacological investigation of the molecular interaction between CBD and TRPV1.
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Affiliation(s)
| | | | | | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry (ICB), National Research Council (CNR), Pozzuoli, Italy.,Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health, Faculty of Medicine and Faculty of Agricultural and Food Sciences, Université Laval, Québec City, Canada
| | - Benjamin J Whalley
- GW Research Ltd., Cambridge, United Kingdom.,School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Reading, Berkshire, United Kingdom
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Talbot SR, Biernot S, Bleich A, van Dijk RM, Ernst L, Häger C, Helgers SOA, Koegel B, Koska I, Kuhla A, Miljanovic N, Müller-Graff FT, Schwabe K, Tolba R, Vollmar B, Weegh N, Wölk T, Wolf F, Wree A, Zieglowski L, Potschka H, Zechner D. Defining body-weight reduction as a humane endpoint: a critical appraisal. Lab Anim 2019; 54:99-110. [PMID: 31665969 DOI: 10.1177/0023677219883319] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In many animal experiments scientists and local authorities define a body-weight reduction of 20% or more as severe suffering and thereby as a potential parameter for humane endpoint decisions. In this study, we evaluated distinct animal experiments in multiple research facilities, and assessed whether 20% body-weight reduction is a valid humane endpoint criterion in rodents. In most experiments (restraint stress, distinct models for epilepsy, pancreatic resection, liver resection, caloric restrictive feeding and a mouse model for Dravet syndrome) the animals lost less than 20% of their original body weight. In a glioma model, a fast deterioration in body weight of less than 20% was observed as a reliable predictor for clinical deterioration. In contrast, after induction of chronic diabetes or acute colitis some animals lost more than 20% of their body weight without exhibiting major signs of distress. In these two animal models an exclusive application of the 20% weight loss criterion for euthanasia might therefore result in an unnecessary loss of animals. However, we also confirmed that this criterion can be a valid parameter for defining the humane endpoint in other animal models, especially when it is combined with additional criteria for evaluating distress. In conclusion, our findings strongly suggest that experiment and model specific considerations are necessary for the rational integration of the parameter 'weight loss' in severity assessment schemes and humane endpoint criteria. A flexible implementation tailored to the experiment or intervention by scientists and authorities is therefore highly recommended.
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Affiliation(s)
- Steven R Talbot
- Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | - Svenja Biernot
- Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | - Andre Bleich
- Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | | | - Lisa Ernst
- Institute for Laboratory Animal Science & Experimental Surgery and Central Laboratory for Laboratory Animal Science, RWTH Aachen University, Germany
| | - Christine Häger
- Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | | | - Babette Koegel
- Institute for Laboratory Animal Science & Experimental Surgery and Central Laboratory for Laboratory Animal Science, RWTH Aachen University, Germany
| | - Ines Koska
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Germany
| | - Angela Kuhla
- Rudolf-Zenker-Institute of Experimental Surgery, University Medical Center, Rostock, Germany
| | - Nina Miljanovic
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Germany
| | | | - Kerstin Schwabe
- Department of Neurosurgery, Hannover Medical School, Germany
| | - Rene Tolba
- Institute for Laboratory Animal Science & Experimental Surgery and Central Laboratory for Laboratory Animal Science, RWTH Aachen University, Germany
| | - Brigitte Vollmar
- Rudolf-Zenker-Institute of Experimental Surgery, University Medical Center, Rostock, Germany
| | - Nora Weegh
- Institute for Laboratory Animal Science, Hannover Medical School, Germany
| | - Tjark Wölk
- Rudolf-Zenker-Institute of Experimental Surgery, University Medical Center, Rostock, Germany
| | - Fabio Wolf
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Germany
| | - Andreas Wree
- Institute of Anatomy, University Medical Center, Rostock, Germany
| | - Leonie Zieglowski
- Institute for Laboratory Animal Science & Experimental Surgery and Central Laboratory for Laboratory Animal Science, RWTH Aachen University, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Germany
| | - Dietmar Zechner
- Rudolf-Zenker-Institute of Experimental Surgery, University Medical Center, Rostock, Germany
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15
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Wu MM, Zhang X, Asher MJ, Thayer SA. Druggable targets of the endocannabinoid system: Implications for the treatment of HIV-associated neurocognitive disorder. Brain Res 2019; 1724:146467. [PMID: 31539547 DOI: 10.1016/j.brainres.2019.146467] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/24/2022]
Abstract
HIV-associated neurocognitive disorder (HAND) affects nearly half of all HIV-infected individuals. Synaptodendritic damage correlates with neurocognitive decline in HAND, and many studies have demonstrated that HIV-induced neuronal injury results from excitotoxic and inflammatory mechanisms. The endocannabinoid (eCB) system provides on-demand protection against excitotoxicity and neuroinflammation. Here, we discuss evidence of the neuroprotective and anti-inflammatory properties of the eCB system from in vitro and in vivo studies. We examine the pharmacology of the eCB system and evaluate the therapeutic potential of drugs that modulate eCB signaling to treat HAND. Finally, we provide perspective on the need for additional studies to clarify the role of the eCB system in HIV neurotoxicity and speculate that strategies that enhance eCB signaling might slow cognitive decline in HAND.
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Affiliation(s)
- Mariah M Wu
- Graduate Program in Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| | - Xinwen Zhang
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| | - Melissa J Asher
- Graduate Program in Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| | - Stanley A Thayer
- Graduate Program in Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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16
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Geresu B, Canseco-Alba A, Sanabria B, Lin Z, Liu QR, Onaivi ES, Engidawork E. Involvement of CB2 Receptors in the Neurobehavioral Effects of Catha Edulis (Vahl) Endl. (Khat) in Mice. Molecules 2019; 24:E3164. [PMID: 31480324 PMCID: PMC6749201 DOI: 10.3390/molecules24173164] [Citation(s) in RCA: 5] [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: 07/19/2019] [Revised: 08/26/2019] [Accepted: 08/29/2019] [Indexed: 12/13/2022] Open
Abstract
There is behavioral evidence for the interaction between crude khat extract and the endocannabinoid system, whereby the endocannabinoid system alters khat extract-mediated behavioral effects through modulation of the monoaminergic system. The objective of this study was to investigate the role of the endocannabinoid system on the neurobehavioral effect of khat extract in mice following concomitant administration of khat extract and the CB2R agonist, JWH133. Locomotor activity test, immunohistochemistry, and reverse transcriptase polymerase chain reaction technique were utilized to assess locomotor activity, tyrosine hydroxylase immunoreactivity, and expression of dopamine transporter mRNA gene. The results show sub-acute administration of khat extract alone increased locomotor activity in mice and co-administration of the CB2R agonist, JWH133, reduced khat extract induced hyperlocomotor activity. The data revealed that cell type specific deletion of CB2Rs on dopaminergic neurons increased the hyperlocomotor behavior of khat extract. Furthermore, the results revealed that khat extract attenuated MPTP induced motor deficits, which is enhanced by JWH133. Khat extract also increased expression of tyrosine hydroxylase positive cells and expression of dopamine transporter mRNA gene in wild type mice. Nevertheless, JWH133 did not alter the effect of khat extract on tyrosine hydroxylase immunoreactivity and dopamine transporter mRNA expression when given together with khat extract. Taken together, the results suggest that the CB2Rs selectively interact with khat extract-mediated locomotor effects and could be utilized as therapeutic target in central nervous system movement disorders associated with dopamine dysregulation.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
- Animals
- Behavior, Animal/drug effects
- Brain/drug effects
- Brain/physiology
- Cannabinoids/administration & dosage
- Cannabinoids/pharmacology
- Catha/chemistry
- Dopamine Plasma Membrane Transport Proteins/genetics
- Dopamine Plasma Membrane Transport Proteins/metabolism
- Dopaminergic Neurons/drug effects
- Dopaminergic Neurons/physiology
- Gene Deletion
- Gene Expression Regulation/drug effects
- Mice, Inbred C57BL
- Mice, Knockout
- Motor Activity/drug effects
- Plant Extracts/pharmacology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/metabolism
- Tyrosine 3-Monooxygenase/metabolism
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Affiliation(s)
- Berhanu Geresu
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, Addis Ababa University, 1176 Addis Ababa, Ethiopia
| | - Ana Canseco-Alba
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| | - Branden Sanabria
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| | - Zhicheng Lin
- Department of Psychiatry, Harvard Medical School, Psychiatric Neurogenomics, Division of Alcohol and Drug Abuse, and Mailman Neuroscience Research Center, McLean Hospital, Belmont, MA 02478, USA
| | - Qing-Rong Liu
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Emmanuel S Onaivi
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA.
| | - Ephrem Engidawork
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, Addis Ababa University, 1176 Addis Ababa, Ethiopia.
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17
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Rodrigues RS, Lourenço DM, Paulo SL, Mateus JM, Ferreira MF, Mouro FM, Moreira JB, Ribeiro FF, Sebastião AM, Xapelli S. Cannabinoid Actions on Neural Stem Cells: Implications for Pathophysiology. Molecules 2019; 24:E1350. [PMID: 30959794 PMCID: PMC6480122 DOI: 10.3390/molecules24071350] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/01/2019] [Accepted: 04/03/2019] [Indexed: 02/06/2023] Open
Abstract
With the increase of life expectancy, neurodegenerative disorders are becoming not only a health but also a social burden worldwide. However, due to the multitude of pathophysiological disease states, current treatments fail to meet the desired outcomes. Therefore, there is a need for new therapeutic strategies focusing on more integrated, personalized and effective approaches. The prospect of using neural stem cells (NSC) as regenerative therapies is very promising, however several issues still need to be addressed. In particular, the potential actions of pharmacological agents used to modulate NSC activity are highly relevant. With the ongoing discussion of cannabinoid usage for medical purposes and reports drawing attention to the effects of cannabinoids on NSC regulation, there is an enormous, and yet, uncovered potential for cannabinoids as treatment options for several neurological disorders, specifically when combined with stem cell therapy. In this manuscript, we review in detail how cannabinoids act as potent regulators of NSC biology and their potential to modulate several neurogenic features in the context of pathophysiology.
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Affiliation(s)
- Rui S Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Diogo M Lourenço
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Sara L Paulo
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Joana M Mateus
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Miguel F Ferreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Francisco M Mouro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - João B Moreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Filipa F Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Sara Xapelli
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
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18
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von Rüden EL, Wolf F, Gualtieri F, Keck M, Hunt CR, Pandita TK, Potschka H. Genetic and Pharmacological Targeting of Heat Shock Protein 70 in the Mouse Amygdala-Kindling Model. ACS Chem Neurosci 2019; 10:1434-1444. [PMID: 30396268 DOI: 10.1021/acschemneuro.8b00475] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Inflammatory responses involving Toll-like receptor signaling represent a key factor contributing to epileptogenesis. Thus, it is of particular interest to explore the relevance of toll-like receptor ligands and modulators, such as heat shock protein 70 (HSP70). Motivated by recent findings demonstrating an upregulation of HSP70 in a model of epileptogenesis, we analyzed the consequences of genetic and pharmacological targeting of HSP70 expression in a mouse kindling paradigm. Lack of inducible HSP70 resulted in increased prekindling seizure thresholds. However, at threshold stimulation the deficiency-promoted seizure spread, as indicated by an increased seizure severity. Subsequent kindling stimulations elicited more severe seizures in knockout mice, whereas endogenous termination of seizure activity remained unaffected with duration of behavioral and electrographic seizure activity comparable to that of wild-type mice. Interestingly, HSP70 deficiency resulted in enhanced microglia activation in the CA1 region. Next, we assessed a pharmacological targeting approach aiming to promote HSP70 expression. Celastrol treatment had no impact on kindling progression but reduced postkindling seizure thresholds and enhanced microglia activation in CA1 and CA3. In conclusion, the findings from HSP70-knockout mice support a protective role of HSP70 with an effect on microglia activation and spread of seizure activity. Unexpectedly, celastrol administration resulted in detrimental consequences. These findings should be considered as a warning about the general safety of celastrol as a drug candidate. The impact of pathophysiological mechanisms on the quality of celastrol effects requires comprehensive future studies exploring influencing factors. Moreover, alternate strategies to increase HSP70 expression should be further developed and validated.
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Affiliation(s)
- Eva-Lotta von Rüden
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Koeniginstraße 16, D-80539 Munich, Germany
| | - Fabio Wolf
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Koeniginstraße 16, D-80539 Munich, Germany
| | - Fabio Gualtieri
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Koeniginstraße 16, D-80539 Munich, Germany
| | - Michael Keck
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Koeniginstraße 16, D-80539 Munich, Germany
| | - Clayton R. Hunt
- Department of Radiation Oncology, The Houston Methodist Research Institute, 6550 Fannin Street SM8-024, Houston, Texas 77030, United States
| | - Tej K. Pandita
- Department of Radiation Oncology, The Houston Methodist Research Institute, 6550 Fannin Street SM8-024, Houston, Texas 77030, United States
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Koeniginstraße 16, D-80539 Munich, Germany
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19
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Nazıroğlu M, Taner AN, Balbay E, Çiğ B. Inhibitions of anandamide transport and FAAH synthesis decrease apoptosis and oxidative stress through inhibition of TRPV1 channel in an in vitro seizure model. Mol Cell Biochem 2018; 453:143-155. [PMID: 30159798 DOI: 10.1007/s11010-018-3439-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/24/2018] [Indexed: 02/03/2023]
Abstract
The expression level of TRPV1 is high in hippocampus which is a main epileptic area in the brain. In addition to the actions of capsaicin (CAP) and reactive oxygen species (ROS), the TRPV1 channel is activated in neurons by endogenous cannabinoid, anandamide (AEA). In the current study, we investigated the role of inhibitors of TRPV1 (capsazepine, CPZ), AEA transport (AM404), and FAAH (URB597) on the modulation of Ca2+ entry, apoptosis, and oxidative stress in in vitro seizure-induced rat hippocampus and human glioblastoma (DBTRG) cell line. The seizure was induced in the hippocampal and DBTRG neurons using in vitro 4-aminopyridine (4-AP) to trigger a seizure-like activity model. CPZ and AM404 were fully effective in reversing 4-AP-induced intracellular free Ca2+ concentration of the hippocampus and TRPV1 current density of DBTRG. However, AEA and CAP did not activate TRPV1 in the URB597-treated neurons. Hence, we observed TRPV1 blocker effects of URB597 in the DBTRG neurons. In addition, the AM404 and CPZ treatments decreased intracellular ROS production, mitochondrial membrane depolarization, apoptosis, caspases 3 and 9 values in the hippocampus. In conclusion, the results indicate that inhibition of AEA transport, FAAH synthesis, and TRPV1 activity can result in remarkable neuroprotective effects in the epileptic neurons. Possible molecular pathways of involvement of capsazepine (CPZ) and AM4040 in anandamide and capsaicin (CAP)-induced apoptosis, oxidative stress, and Ca2+ accumulation through TRPV1 channel in the seizure-induced rat hippocampus and human glioblastoma neurons. The TRPV1 channel is activated by different stimuli including reactive oxygen species (ROS), anandamide (AEA), and CAP and it is blocked by capsazepine (CPZ). Cannabinoid receptor type 1 (CB1) is also activated by AEA. The AEA levels in cytosol are decreased by fatty acid amide hydrolase (FAAH) enzyme. Inhibition of FAAH through URB597 induces stimulation of CB1 receptor through accumulation AEA. URB597 acts antiepileptic effects through inhibition of TRPV1. Overloaded Ca2+ concentration of mitochondria can induce an apoptotic program by stimulating the release of apoptosis-promoting factors such as caspases 3 and caspase 9 by generating ROS due to respiratory chain damage. AM404 and CPZ reduce TRPV1 channel activation and Ca2+ entry in the in vitro 4-AP seizure model-induced hippocampal and glioblastoma neurons.
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Affiliation(s)
- Mustafa Nazıroğlu
- Neuroscience Research Center, Suleyman Demirel University, 32260, Isparta, Turkey. .,Department of Biophysics, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey.
| | - Afife Nur Taner
- Medicine Faculty, Suleyman Demirel University, Isparta, Turkey
| | - Esra Balbay
- Medicine Faculty, Suleyman Demirel University, Isparta, Turkey
| | - Bilal Çiğ
- Department of Biophysics, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey
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Cnidarian peptide neurotoxins: a new source of various ion channel modulators or blockers against central nervous systems disease. Drug Discov Today 2018; 24:189-197. [PMID: 30165198 DOI: 10.1016/j.drudis.2018.08.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/13/2018] [Accepted: 08/10/2018] [Indexed: 01/17/2023]
Abstract
Cnidaria provide the largest source of bioactive peptides for new drug development. The venoms contain enzymes, potent pore-forming toxins and neurotoxins. The neurotoxins can immobilize predators rapidly when discharged via modifying sodium-channel-gating or blocking the potassium channel during the repolarization stage. Most cnidarian neurotoxins remain conserved under the strong influence of negative selection. Neuroactive peptides targeting the central nervous system through affinity with ion channels could provide insight leading to drug treatment of neurological diseases, which arise from ion channel dysfunctions. Although marine resources offer thousands of possible peptides, only one peptide derived from Cnidaria: ShK-186, also named dalazatide, has reached the pharmaceutical market. This review focuses on neuroprotective agents derived from cnidarian neurotoxic peptides.
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Sugaya Y, Kano M. Control of excessive neural circuit excitability and prevention of epileptic seizures by endocannabinoid signaling. Cell Mol Life Sci 2018; 75:2793-2811. [PMID: 29737364 PMCID: PMC11105219 DOI: 10.1007/s00018-018-2834-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/23/2018] [Accepted: 05/02/2018] [Indexed: 12/12/2022]
Abstract
Progress in research on endocannabinoid signaling has greatly advanced our understanding of how it controls neural circuit excitability in health and disease. In general, endocannabinoid signaling at excitatory synapses suppresses seizures by inhibiting glutamate release. In contrast, endocannabinoid signaling promotes seizures by inhibiting GABA release at inhibitory synapses. The physiological distribution of endocannabinoid signaling molecules becomes disrupted with the development of epileptic focus in patients with mesial temporal lobe epilepsy and in animal models of experimentally induced epilepsy. Augmentation of endocannabinoid signaling can promote the development of epileptic focus at initial stages. However, at later stages, increased endocannabinoid signaling delays it and suppresses spontaneous seizures. Thus, the regulation of endocannabinoid signaling at specific synapses that cause hyperexcitability during particular stages of disease development may be effective for treating epilepsy and epileptogenesis.
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Affiliation(s)
- Yuki Sugaya
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-0033, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Tokyo, 113-0033, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-0033, Japan.
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Tokyo, 113-0033, Japan.
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Genetic Modulation of HSPA1A Accelerates Kindling Progression and Exerts Pro-convulsant Effects. Neuroscience 2018; 386:108-120. [PMID: 29964156 DOI: 10.1016/j.neuroscience.2018.06.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/05/2018] [Accepted: 06/19/2018] [Indexed: 12/20/2022]
Abstract
Strong evidence exists that Toll-like receptor (TLR)-mediated effects on microglia functional states can promote ictogenesis and epileptogenesis. So far, research has focused on the role of high-mobility group box protein 1 as an activator of TLRs. However, the development of targeting strategies might need to consider a role of additional receptor ligands. Considering the fact that heat shock protein A1 (hsp70) has been confirmed as a TLR 2 and 4 ligand, we have explored the consequences of its overexpression in a mouse kindling paradigm. The genetic modulation enhanced seizure susceptibility with lowered seizure thresholds prior to kindling. In contrast to wildtype (WT) mice, HSPA1A transgenic (TG) mice exhibited generalized seizures very early during the kindling paradigm. Along with an increased seizure severity, seizure duration proved to be prolonged in TG mice during this phase. Toward the end of the stimulation phase seizure parameters of WT mice reached comparable levels. However, a difference between genotypes was still evident when comparing seizure parameters during the post-kindling threshold determination. Surprisingly, HSPA1A overexpression did not affect microglia activation in the hippocampus. In conclusion, the findings demonstrate that hsp70 can exert pro-convulsant effects promoting ictogenesis in naïve animals. The pronounced impact on the response to subsequent stimulations gives first evidence that genetic HSPA1A upregulation may also contribute to epileptogenesis. Thus, strategies inhibiting hsp70 or its expression might be of interest for prevention of seizures and epilepsy. However, conclusions about a putative pro-epileptogenic effect of hsp70 require further investigations in models with development of spontaneous recurrent seizures.
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Mardani P, Oryan S, Sarihi A, Alaei E, Komaki A, Mirnajafi-Zadeh J. Endocannabinoid CB1 receptors are involved in antiepileptogenic effect of low frequency electrical stimulation during perforant path kindling in rats. Epilepsy Res 2018; 144:71-81. [PMID: 29800824 DOI: 10.1016/j.eplepsyres.2018.05.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 04/27/2018] [Accepted: 05/14/2018] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Administration of low-frequency electrical stimulation (LFS) at the kindling site has an antiepileptogenic effect. In the present study, we investigated the role of cannabinoid receptors type 1 (CB1) in mediating the inhibitory effects of LFS on the development of perforant path kindled seizures. METHODS For seizure generation, rats were kindled by electrical stimulation of perforant path in semi-rapid kindling manner (12 stimulations per day at 10 min intervals at afterdischarge threshold intensity).To determine the effect of LFS (0.1 ms pulse duration at 1 Hz, 800 pulses) on seizure generation, LFS was applied to the perforant path 5 min after the last kindling stimulation daily. AM281, a CB1 receptor antagonist, was microinjected into the lateral ventricle immediately after the last kindling stimulation (before LFS application) at the doses of 0.5 and 2 μg/μl during kindling procedure. The expression of cannabinoid receptors in the dentate gyrus was also investigated using immunohistochemistry. RESULTS Application of LFS had inhibitory effect on development of kindled seizures (kindling rate). Microinjection of AM281 (0.5 μg/μl) immediately after the last kindling stimulation (before LFS application) reduced the inhibitory effect of LFS on the kindling rate and suppressed the effects of LFS on potentiation (increasing the magnitude) of both population spike amplitude and population excitatory postsynaptic potential slope during kindling acquisition. AM281 pretreatment also prevented the effects of LFS on kindling-induced increase in early and late paired pulse depression. The higher dose of AM281 (2 μg/μl) failed to exert the effects observed with its lower dose (0.5 μg/μl). In addition, there was a decreased CB1 receptors immunostaining in kindled animals compared to control. However, application of LFS following kindling stimulations led to overexpression of CB1 receptors in the dentate gyrus. CONCLUSION Obtained results showed that activation of overexpressed cannabinoid CB1 receptors by endogenous cannabinoids may have a role in mediating the inhibitory effect of LFS on perforant path kindled seizures.
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Affiliation(s)
- Parastoo Mardani
- Department of Animal Biology, Faculty of Biological Science, Kharazmi University, Tehran, Iran; Department of Biology, Faculty of Sciences, Payame Noor University, Iran.
| | - Shahrbanoo Oryan
- Department of Animal Biology, Faculty of Biological Science, Kharazmi University, Tehran, Iran
| | - Abdolrahman Sarihi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Elham Alaei
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Alireza Komaki
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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Khan AA, Shekh-Ahmad T, Khalil A, Walker MC, Ali AB. Cannabidiol exerts antiepileptic effects by restoring hippocampal interneuron functions in a temporal lobe epilepsy model. Br J Pharmacol 2018; 175:2097-2115. [PMID: 29574880 PMCID: PMC5979781 DOI: 10.1111/bph.14202] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/13/2017] [Accepted: 02/27/2018] [Indexed: 12/29/2022] Open
Abstract
Background and Purpose A non‐psychoactive phytocannabinoid, cannabidiol (CBD), shows promising results as an effective potential antiepileptic drug in some forms of refractory epilepsy. To elucidate the mechanisms by which CBD exerts its anti‐seizure effects, we investigated its effects at synaptic connections and on the intrinsic membrane properties of hippocampal CA1 pyramidal cells and two major inhibitory interneurons: fast spiking, parvalbumin (PV)‐expressing and adapting, cholecystokinin (CCK)‐expressing interneurons. We also investigated whether in vivo treatment with CBD altered the fate of CCK and PV interneurons using immunohistochemistry. Experimental Approach Electrophysiological intracellular whole‐cell recordings combined with neuroanatomy were performed in acute brain slices of rat temporal lobe epilepsy in in vivo (induced by kainic acid) and in vitro (induced by Mg2+‐free solution) epileptic seizure models. For immunohistochemistry experiments, CBD was administered in vivo (100 mg·kg−1) at zero time and 90 min post status epilepticus, induced with kainic acid. Key Results Bath application of CBD (10 μM) dampened excitability at unitary synapses between pyramidal cells but enhanced inhibitory synaptic potentials elicited by fast spiking and adapting interneurons at postsynaptic pyramidal cells. Furthermore, CBD restored impaired membrane excitability of PV, CCK and pyramidal cells in a cell type‐specific manner. These neuroprotective effects of CBD were corroborated by immunohistochemistry experiments that revealed a significant reduction in atrophy and death of PV‐ and CCK‐expressing interneurons after CBD treatment. Conclusions and Implications Our data suggest that CBD restores excitability and morphological impairments in epileptic models to pre‐epilepsy control levels through multiple mechanisms to reinstate normal network function.
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Affiliation(s)
| | | | | | | | - Afia B Ali
- UCL School of Pharmacy, London, WC1N 1AX, UK
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Batten SR, Matveeva EA, Whiteheart SW, Vanaman TC, Gerhardt GA, Slevin JT. Linking kindling to increased glutamate release in the dentate gyrus of the hippocampus through the STXBP5/tomosyn-1 gene. Brain Behav 2017; 7:e00795. [PMID: 28948088 PMCID: PMC5607557 DOI: 10.1002/brb3.795] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/29/2017] [Accepted: 07/02/2017] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION In kindling, repeated electrical stimulation of certain brain areas causes progressive and permanent intensification of epileptiform activity resulting in generalized seizures. We focused on the role(s) of glutamate and a negative regulator of glutamate release, STXBP5/tomosyn-1, in kindling. METHODS Stimulating electrodes were implanted in the amygdala and progression to two successive Racine stage 5 seizures was measured in wild-type and STXBP5/tomosyn-1-/- (Tom-/-) animals. Glutamate release measurements were performed in distinct brain regions using a glutamate-selective microelectrode array (MEA). RESULTS Naïve Tom-/- mice had significant increases in KCl-evoked glutamate release compared to naïve wild type as measured by MEA of presynaptic release in the hippocampal dentate gyrus (DG). Kindling progression was considerably accelerated in Tom-/- mice, requiring fewer stimuli to reach a fully kindled state. Following full kindling, MEA measurements of both kindled Tom+/+ and Tom-/- mice showed significant increases in KCl-evoked and spontaneous glutamate release in the DG, indicating a correlation with the fully kindled state independent of genotype. Resting glutamate levels in all hippocampal subregions were significantly lower in the kindled Tom-/- mice, suggesting possible changes in basal control of glutamate circuitry in the kindled Tom-/- mice. CONCLUSIONS Our studies demonstrate that increased glutamate release in the hippocampal DG correlates with acceleration of the kindling process. Although STXBP5/tomosyn-1 loss increased evoked glutamate release in naïve animals contributing to their prokindling phenotype, the kindling process can override any attenuating effect of STXBP5/tomosyn-1. Loss of this "braking" effect of STXBP5/tomosyn-1 on kindling progression may set in motion an alternative but ultimately equally ineffective compensatory response, detected here as reduced basal glutamate release.
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Affiliation(s)
- Seth R. Batten
- Department of PsychologyUniversity of KentuckyCollege of Arts and SciencesLexingtonKYUSA
| | - Elena A. Matveeva
- Department of Molecular & Cellular BiochemistryUniversity of Kentucky Medical CenterLexingtonKYUSA
| | - Sidney W. Whiteheart
- Department of Molecular & Cellular BiochemistryUniversity of Kentucky Medical CenterLexingtonKYUSA
| | - Thomas C. Vanaman
- Department of Molecular & Cellular BiochemistryUniversity of Kentucky Medical CenterLexingtonKYUSA
| | - Greg A. Gerhardt
- Department of NeuroscienceUniversity of Kentucky Medical CenterLexingtonKYUSA
- Department of NeurologyUniversity of Kentucky Medical CenterLexingtonKYUSA
| | - John T. Slevin
- Neurology ServiceVeterans Affairs Medical CenterLexingtonKYUSA
- Department of NeurologyUniversity of Kentucky Medical CenterLexingtonKYUSA
- Department of Pharmacology and Nutritional SciencesUniversity of Kentucky Medical CenterLexingtonKYUSA
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Freundt-Revilla J, Kegler K, Baumgärtner W, Tipold A. Spatial distribution of cannabinoid receptor type 1 (CB1) in normal canine central and peripheral nervous system. PLoS One 2017; 12:e0181064. [PMID: 28700706 PMCID: PMC5507289 DOI: 10.1371/journal.pone.0181064] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 06/26/2017] [Indexed: 12/18/2022] Open
Abstract
The endocannabinoid system is a regulatory pathway consisting of two main types of cannabinoid receptors (CB1 and CB2) and their endogenous ligands, the endocannabinoids. The CB1 receptor is highly expressed in the central and peripheral nervous systems (PNS) in mammalians and is involved in neuromodulatory functions. Since endocannabinoids were shown to be elevated in cerebrospinal fluid of epileptic dogs, knowledge about the species specific CB receptor expression in the nervous system is required. Therefore, we assessed the spatial distribution of CB1 receptors in the normal canine CNS and PNS. Immunohistochemistry of several regions of the brain, spinal cord and peripheral nerves from a healthy four-week-old puppy, three six-month-old dogs, and one ten-year-old dog revealed strong dot-like immunoreactivity in the neuropil of the cerebral cortex, Cornu Ammonis (CA) and dentate gyrus of the hippocampus, midbrain, cerebellum, medulla oblongata and grey matter of the spinal cord. Dense CB1 expression was found in fibres of the globus pallidus and substantia nigra surrounding immunonegative neurons. Astrocytes were constantly positive in all examined regions. CB1 labelled neurons and satellite cells of the dorsal root ganglia, and myelinating Schwann cells in the PNS. These results demonstrate for the first time the spatial distribution of CB1 receptors in the healthy canine CNS and PNS. These results can be used as a basis for further studies aiming to elucidate the physiological consequences of this particular anatomical and cellular distribution.
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Affiliation(s)
- Jessica Freundt-Revilla
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Kristel Kegler
- Center for Systems Neuroscience, Hannover, Germany
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
| | - Wolfgang Baumgärtner
- Center for Systems Neuroscience, Hannover, Germany
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
| | - Andrea Tipold
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
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Remmers F, Lange MD, Hamann M, Ruehle S, Pape HC, Lutz B. Addressing sufficiency of the CB1 receptor for endocannabinoid-mediated functions through conditional genetic rescue in forebrain GABAergic neurons. Brain Struct Funct 2017; 222:3431-3452. [PMID: 28393261 PMCID: PMC5676814 DOI: 10.1007/s00429-017-1411-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 03/20/2017] [Indexed: 12/18/2022]
Abstract
Genetic inactivation of the cannabinoid CB1 receptor gene in different cell types in the brain has previously revealed necessary functions for distinct synaptic plasticity processes and behaviors. Here, we sought to identify CB1 receptor expression sites that are minimally required to reconstruct normal phenotypes. In a CB1-null background, we re-expressed endogenous CB1 receptors in forebrain GABAergic neurons, thereby assessing the sufficiency of CB1 receptors. Depolarization-induced suppression of inhibitory, but not excitatory, transmission was restored in hippocampal and amygdalar circuits. GABAergic CB1 receptors did not convey protection against chemically induced seizures, but prevented the spontaneous mortality observed in CB1 null mutants. Rescue of GABAergic CB1 receptors largely restored normal anxiety-like behavior but improved extinction of learned fear only marginally. This study illustrates that the approach of genetic reconstruction of complex behaviors is feasible. It also revealed distinct degrees of modulation for different emotional behaviors by the GABAergic population of CB1 receptors.
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MESH Headings
- Amygdala/metabolism
- Amygdala/physiology
- Animals
- Anxiety
- Behavior, Animal
- Extinction, Psychological
- Fear
- GABAergic Neurons/physiology
- Hippocampus/metabolism
- Hippocampus/physiology
- Inhibitory Postsynaptic Potentials
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Prosencephalon/physiology
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB1/physiology
- Seizures/chemically induced
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Affiliation(s)
- Floortje Remmers
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55128, Mainz, Germany.
| | - Maren D Lange
- Institute of Physiology I, Westfaelische Wilhelms-University, 48149, Muenster, Germany
| | - Martina Hamann
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Sabine Ruehle
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Hans-Christian Pape
- Institute of Physiology I, Westfaelische Wilhelms-University, 48149, Muenster, Germany
| | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55128, Mainz, Germany
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Aghazadeh Tabrizi M, Baraldi PG, Baraldi S, Gessi S, Merighi S, Borea PA. Medicinal Chemistry, Pharmacology, and Clinical Implications of TRPV1 Receptor Antagonists. Med Res Rev 2016; 37:936-983. [PMID: 27976413 DOI: 10.1002/med.21427] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/24/2016] [Accepted: 11/01/2016] [Indexed: 12/28/2022]
Abstract
Transient receptor potential vanilloid 1 (TRPV1) is an ion channel expressed on sensory neurons triggering an influx of cations. TRPV1 receptors function as homotetramers responsive to heat, proinflammatory substances, lipoxygenase products, resiniferatoxin, endocannabinoids, protons, and peptide toxins. Its phosphorylation increases sensitivity to both chemical and thermal stimuli, while desensitization involves a calcium-dependent mechanism resulting in receptor dephosphorylation. TRPV1 functions as a sensor of noxious stimuli and may represent a target to avoid pain and injury. TRPV1 activation has been associated to chronic inflammatory pain and peripheral neuropathy. Its expression is also detected in nonneuronal areas such as bladder, lungs, and cochlea where TRPV1 activation is responsible for pathology development of cystitis, asthma, and hearing loss. This review offers a comprehensive overview about TRPV1 receptor in the pathophysiology of chronic pain, epilepsy, cough, bladder disorders, diabetes, obesity, and hearing loss, highlighting how drug development targeting this channel could have a clinical therapeutic potential. Furthermore, it summarizes the advances of medicinal chemistry research leading to the identification of highly selective TRPV1 antagonists and their analysis of structure-activity relationships (SARs) focusing on new strategies to target this channel.
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Affiliation(s)
- Mojgan Aghazadeh Tabrizi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Pier Giovanni Baraldi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Stefania Baraldi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Stefania Gessi
- Section of Pharmacology, Department of Medical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Stefania Merighi
- Section of Pharmacology, Department of Medical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Pier Andrea Borea
- Section of Pharmacology, Department of Medical Sciences, University of Ferrara, 44121, Ferrara, Italy
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Wong JC, Escayg A. Turning Up the Heat on Endocannabinoid Signaling. Epilepsy Curr 2016; 16:414-415. [PMID: 27857628 PMCID: PMC5106110 DOI: 10.5698/1535-7511-16.6.414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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30
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Sugaya Y, Yamazaki M, Uchigashima M, Kobayashi K, Watanabe M, Sakimura K, Kano M. Crucial Roles of the Endocannabinoid 2-Arachidonoylglycerol in the Suppression of Epileptic Seizures. Cell Rep 2016; 16:1405-1415. [PMID: 27452464 DOI: 10.1016/j.celrep.2016.06.083] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 05/01/2016] [Accepted: 06/21/2016] [Indexed: 01/13/2023] Open
Abstract
Endocannabinoid signaling is considered to suppress excessive excitability of neural circuits and to protect the brain from seizures. However, the precise mechanisms of this effect are poorly understood. Here, we report that 2-arachidonoylglycerol (2-AG), one of the two major endocannabinoids, is crucial for suppressing seizures. We found that kainate-induced seizures in mice lacking the 2-AG synthesizing enzyme, diacylglycerol lipase α, were much more severe compared with those in cannabinoid CB1 receptor knockout mice and were comparable to those in mice lacking both CB1- and CB2-receptor-mediated signaling. In the dentate gyrus, 2-AG suppressed excitatory input around the inner and middle molecular layers through CB1 and presumably CB2 receptors, respectively. This 2-AG-mediated suppression contributed to decreased granule cell excitability and the dampening of seizures. Furthermore, lack of 2-AG signaling enhanced kindling epileptogenesis and spontaneous seizures after kainate-induced status epilepticus. These results highlight critical roles of 2-AG signaling in the suppression of epileptic seizures.
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Affiliation(s)
- Yuki Sugaya
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Motokazu Uchigashima
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
| | - Masahiko Watanabe
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
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Abstract
Epilepsy has 2-3% incidence worldwide. However, present antiepileptic drugs provide only partial control of seizures. Calcium ion accumulation in hippocampal neurons has long been known as a major contributor to the etiology of epilepsy. TRPV1 is a calcium-permeable channel and mediator of epilepsy in the hippocampus. TRPV1 is expressed in epileptic brain areas such as CA1 area and dentate gyrus of the hippocampus. Here the author reviews the patent literature on novel molecules targeting TRPV1 that are currently being investigated in the laboratory and are candidates for future clinical evaluation in the management of epilepsy. A limited number of recent reports have implicated TRPV1 in the induction or treatment of epilepsy suggesting that this may be new area for potential drugs targeting this debilitating disease. Thus activation of TRPV1 by oxidative stress, resiniferatoxin, cannabinoid receptor (CB1) activators (i.e. anandamide) or capsaicin induced epileptic effects, and these effects could be reduced by appropriate inhibitors, including capsazepine (CPZ), 5'-iodoresiniferatoxin (IRTX), resolvins, and CB1 antagonists. It has been also reported that CPZ and IRTX reduced spontaneous excitatory synaptic transmission through modulation of glutaminergic systems and desensitization of TRPV1 channels in the hippocampus of rats. Immunocytochemical studies indicated that TRPV1 channel expression increased in the hippocampus of mice and patients with temporal lobe epilepsy. Taken together, findings in the current literature support a role for calcium ion accumulation through TRPV1 channels in the etiology of epileptic seizures, indicating that inhibition of TRPV1 in the hippocampus may possibly be a novel target for prevention of epileptic seizures.
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Affiliation(s)
- Mustafa Nazıroğlu
- Director of Neuroscience Research Center, Suleyman Demirel University, TR-32260, Isparta, Turkey.
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32
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Dentate cannabinoid-sensitive interneurons undergo unique and selective strengthening of mutual synaptic inhibition in experimental epilepsy. Neurobiol Dis 2016; 89:23-35. [PMID: 26804027 DOI: 10.1016/j.nbd.2016.01.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 01/12/2016] [Accepted: 01/19/2016] [Indexed: 11/22/2022] Open
Abstract
Altered inhibition is a salient feature of hippocampal network reorganization in epilepsy. Hippocampal pyramidal cells and dentate granule cells show specific reduction in cannabinoid receptor type 1 (CB1R)-sensitive GABAergic inputs in experimental epilepsy. In the dentate gyrus, CB1Rs regulate synaptic release from accommodating interneurons (AC-INs) with adapting firing characteristics and axonal projections in the molecular layer, but not from fast-spiking basket cells (FS-BCs). However, it is not known whether the intrinsic physiology and synaptic inhibition of AC-INs responsible for CB1R-sensitive inhibition is altered in epilepsy. Using the pilocarpine-induced status epilepticus (SE) model of epilepsy, we find that the basic physiological characteristics of AC-INs in epileptic rats are not different from age-matched controls. In paired interneuronal recordings, the amplitude of unitary inhibitory synaptic currents (uIPSCs) between AC-INs doubled after SE. Non-stationary noise analysis revealed that the post-SE strengthening of synapses between AC-INs resulted from an increase in postsynaptic receptors. Baseline synaptic release and CB1R antagonist enhancement of release at synapses between AC-INs were not different between control and post-SE rats. Additionally, uIPSC amplitude in FS-BCs to AC-INs pairs was unchanged after SE indicating input-specific microcircuit alterations in inhibitory inputs to AC-INs. At the network level, AC-INs showed no reduction in spontaneous and miniature inhibitory synaptic current (sIPSC or mIPSC) frequency or amplitude after SE. However, AC-IN mIPSC amplitude was persistently enhanced in post-SE and epileptic rats. CB1R agonist reduced the amplitude and suppressed a greater proportion of sIPSCs in AC-INs from post-SE and epileptic rats demonstrating a novel, cell-type specific increase in CB1R-sensitive inhibition of AC-INs after SE. This unique post-SE strengthening of inhibition between AC-INs could lead to activity-dependent suppression of AC-IN firing and compromise dentate CB1R-sensitive inhibition in epilepsy.
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Ibeas Bih C, Chen T, Nunn AVW, Bazelot M, Dallas M, Whalley BJ. Molecular Targets of Cannabidiol in Neurological Disorders. Neurotherapeutics 2015; 12:699-730. [PMID: 26264914 PMCID: PMC4604182 DOI: 10.1007/s13311-015-0377-3] [Citation(s) in RCA: 349] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Cannabis has a long history of anecdotal medicinal use and limited licensed medicinal use. Until recently, alleged clinical effects from anecdotal reports and the use of licensed cannabinoid medicines are most likely mediated by tetrahydrocannabinol by virtue of: 1) this cannabinoid being present in the most significant quantities in these preparations; and b) the proportion:potency relationship between tetrahydrocannabinol and other plant cannabinoids derived from cannabis. However, there has recently been considerable interest in the therapeutic potential for the plant cannabinoid, cannabidiol (CBD), in neurological disorders but the current evidence suggests that CBD does not directly interact with the endocannabinoid system except in vitro at supraphysiological concentrations. Thus, as further evidence for CBD's beneficial effects in neurological disease emerges, there remains an urgent need to establish the molecular targets through which it exerts its therapeutic effects. Here, we conducted a systematic search of the extant literature for original articles describing the molecular pharmacology of CBD. We critically appraised the results for the validity of the molecular targets proposed. Thereafter, we considered whether the molecular targets of CBD identified hold therapeutic potential in relevant neurological diseases. The molecular targets identified include numerous classical ion channels, receptors, transporters, and enzymes. Some CBD effects at these targets in in vitro assays only manifest at high concentrations, which may be difficult to achieve in vivo, particularly given CBD's relatively poor bioavailability. Moreover, several targets were asserted through experimental designs that demonstrate only correlation with a given target rather than a causal proof. When the molecular targets of CBD that were physiologically plausible were considered for their potential for exploitation in neurological therapeutics, the results were variable. In some cases, the targets identified had little or no established link to the diseases considered. In others, molecular targets of CBD were entirely consistent with those already actively exploited in relevant, clinically used, neurological treatments. Finally, CBD was found to act upon a number of targets that are linked to neurological therapeutics but that its actions were not consistent withmodulation of such targets that would derive a therapeutically beneficial outcome. Overall, we find that while >65 discrete molecular targets have been reported in the literature for CBD, a relatively limited number represent plausible targets for the drug's action in neurological disorders when judged by the criteria we set. We conclude that CBD is very unlikely to exert effects in neurological diseases through modulation of the endocannabinoid system. Moreover, a number of other molecular targets of CBD reported in the literature are unlikely to be of relevance owing to effects only being observed at supraphysiological concentrations. Of interest and after excluding unlikely and implausible targets, the remaining molecular targets of CBD with plausible evidence for involvement in therapeutic effects in neurological disorders (e.g., voltage-dependent anion channel 1, G protein-coupled receptor 55, CaV3.x, etc.) are associated with either the regulation of, or responses to changes in, intracellular calcium levels. While no causal proof yet exists for CBD's effects at these targets, they represent the most probable for such investigations and should be prioritized in further studies of CBD's therapeutic mechanism of action.
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Affiliation(s)
- Clementino Ibeas Bih
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
| | - Tong Chen
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
| | | | - Michaël Bazelot
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
- GW Pharmaceuticals Ltd, Sovereign House, Vision Park, Chivers Way, Histon, Cambridge, CB24 9BZ, UK
| | - Mark Dallas
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
| | - Benjamin J Whalley
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK.
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von Rüden EL, Bogdanovic RM, Wotjak CT, Potschka H. Inhibition of monoacylglycerol lipase mediates a cannabinoid 1-receptor dependent delay of kindling progression in mice. Neurobiol Dis 2015; 77:238-45. [PMID: 25796567 DOI: 10.1016/j.nbd.2015.03.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/06/2015] [Accepted: 03/12/2015] [Indexed: 12/20/2022] Open
Abstract
Endocannabinoids, including 2-arachidonoylglycerol (2-AG), activate presynaptic cannabinoid type 1 receptors (CB1R) on inhibitory and excitatory neurons, resulting in a decreased release of neurotransmitters. The event-specific activation of the endocannabinoid system by inhibition of the endocannabinoid degrading enzymes may offer a promising strategy to selectively activate CB1Rs at the site of excessive neuronal activation with the overall goal to prevent the development epilepsy. The aim of this study was to investigate the impact of monoacylglycerol lipase (MAGL) inhibition on the development and progression of epileptic seizures in the kindling model of temporal lobe epilepsy. Therefore, we selectively blocked MAGL by JZL184 (8mg/kg, i.p.) in mice to analyze the effects of increased 2-AG levels on kindling acquisition and to exclude an anticonvulsive potential. Our results showed that JZL184 treatment significantly delayed the development of generalized seizures (p=0.0066) and decreased seizure (p<0.0001) and afterdischarge duration (p<0.001) in the kindling model of temporal lobe epilepsy, but caused only modest effects in fully kindled mice. Moreover, we proved that JZL184 treatment had no effects in conditional CB1R knockout mice lacking expression of the receptor in principle neurons of the forebrain. In conclusion, the data demonstrate that indirect CB1R agonism delays the development of generalized epileptic seizures but has no relevant acute anticonvulsive effects. Furthermore, we confirmed that the effects of JZL184 on kindling progression are CB1R mediated. Thus, the data indicate that the endocannabinoid 2-AG might be a promising target for an anti-epileptogenic approach.
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Affiliation(s)
- E L von Rüden
- Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany; Graduate School of Systemic Neurosciences, Munich, Germany
| | - R M Bogdanovic
- Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany; Graduate School of Systemic Neurosciences, Munich, Germany
| | - C T Wotjak
- Department of Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - H Potschka
- Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany.
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Abstract
The antiepileptic potential of Cannabis sativa preparations has been historically recognized. Recent changes in legal restrictions and new well-documented cases reporting remarkably strong beneficial effects have triggered an upsurge in exploiting medical marijuana in patients with refractory epilepsy. Parallel research efforts in the last decade have uncovered the fundamental role of the endogenous cannabinoid system in controlling neuronal network excitability raising hopes for cannabinoid-based therapeutic approaches. However, emerging data show that patient responsiveness varies substantially, and that cannabis administration may sometimes even exacerbate seizures. Qualitative and quantitative chemical variability in cannabis products and personal differences in the etiology of seizures, or in the pathological reorganization of epileptic networks, can all contribute to divergent patient responses. Thus, the consensus view in the neurologist community is that drugs modifying the activity of the endocannabinoid system should first be tested in clinical trials to establish efficacy, safety, dosing, and proper indication in specific forms of epilepsies. To support translation from anecdote-based practice to evidence-based therapy, the present review first introduces current preclinical and clinical efforts for cannabinoid- or endocannabinoid-based epilepsy treatments. Next, recent advances in our knowledge of how endocannabinoid signaling limits abnormal network activity as a central component of the synaptic circuit-breaker system will be reviewed to provide a framework for the underlying neurobiological mechanisms of the beneficial and adverse effects. Finally, accumulating evidence demonstrating robust synapse-specific pathophysiological plasticity of endocannabinoid signaling in epileptic networks will be summarized to gain better understanding of how and when pharmacological interventions may have therapeutic relevance.
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Affiliation(s)
- István Katona
- Momentum Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, Budapest, 1083, Hungary.
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Abstract
The physiological and pathophysiological functions of the endocannabinoid system have been studied extensively using transgenic and targeted knockout mouse models. The first gene deletions of the cannabinoid CB(1) receptor were described in the late 1990s, soon followed by CB(2) and FAAH mutations in early 2000. These mouse models helped to elucidate the fundamental role of endocannabinoids as retrograde transmitters in the CNS and in the discovery of many unexpected endocannabinoid functions, for example, in the skin, bone and liver. We now have knockout mouse models for almost every receptor and enzyme of the endocannabinoid system. Conditional mutant mice were mostly developed for the CB(1) receptor, which is widely expressed on many different neurons, astrocytes and microglia, as well as on many cells outside the CNS. These mouse strains include "floxed" CB(1) alleles and mice with a conditional re-expression of CB(1). The availability of these mice made it possible to decipher the function of CB(1) in specific neuronal circuits and cell populations or to discriminate between central and peripheral effects. Many of the genetic mouse models were also used in combination with viral expression systems. The purpose of this review is to provide a comprehensive overview of the existing genetic models and to summarize some of the most important discoveries that were made with these animals.
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MESH Headings
- Amidohydrolases/genetics
- Amidohydrolases/metabolism
- Animals
- Endocannabinoids/genetics
- Endocannabinoids/metabolism
- Gene Deletion
- Gene Expression Regulation
- Genotype
- Humans
- Hydrolysis
- Mice, Knockout
- Mice, Mutant Strains
- Monoacylglycerol Lipases/genetics
- Monoacylglycerol Lipases/metabolism
- Mutation
- Phenotype
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
- Signal Transduction/genetics
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Affiliation(s)
- Andreas Zimmer
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany.
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