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Enhancement of endocannabinoid signaling protects against cocaine-induced neurotoxicity. Toxicol Appl Pharmacol 2015; 286:178-87. [PMID: 25933444 DOI: 10.1016/j.taap.2015.04.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/15/2015] [Accepted: 04/21/2015] [Indexed: 10/23/2022]
Abstract
Cocaine is an addictive substance with a potential to cause deleterious effects in the brain. The strategies for treating its neurotoxicity, however, are limited. Evidence suggests that the endocannabinoid system exerts neuroprotective functions against various stimuli. Thus, we hypothesized that inhibition of fatty acid amide hydrolase (FAAH), the main enzyme responsible for terminating the actions of the endocannabinoid anandamide, reduces seizures and cell death in the hippocampus in a model of cocaine intoxication. Male Swiss mice received injections of endocannabinoid-related compounds followed by the lowest dose of cocaine that induces seizures, electroencephalographic activity and cell death in the hippocampus. The molecular mechanisms were studied in primary cell culture of this structure. The FAAH inhibitor, URB597, reduced cocaine-induced seizures and epileptiform electroencephalographic activity. The cannabinoid CB1 receptor selective agonist, ACEA, mimicked these effects, whereas the antagonist, AM251, prevented them. URB597 also inhibited cocaine-induced activation and death of hippocampal neurons, both in animals and in primary cell culture. Finally, we investigated if the PI3K/Akt/ERK intracellular pathway, a cell surviving mechanism coupled to CB1 receptor, mediated these neuroprotective effects. Accordingly, URB597 injection increased ERK and Akt phosphorylation in the hippocampus. Moreover, the neuroprotective effect of this compound was reversed by the PI3K inhibitor, LY294002. In conclusion, the pharmacological facilitation of the anandamide/CB1/PI3K signaling protects the brain against cocaine intoxication in experimental models. This strategy may be further explored in the development of treatments for drug-induced neurotoxicity.
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Cannabidiol rescues acute hepatic toxicity and seizure induced by cocaine. Mediators Inflamm 2015; 2015:523418. [PMID: 25999668 PMCID: PMC4427116 DOI: 10.1155/2015/523418] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/07/2015] [Indexed: 12/17/2022] Open
Abstract
Cocaine is a commonly abused illicit drug that causes significant morbidity and mortality. The most severe and common complications are seizures, ischemic strokes, myocardial infarction, and acute liver injury. Here, we demonstrated that acute cocaine intoxication promoted seizure along with acute liver damage in mice, with intense inflammatory infiltrate. Considering the protective role of the endocannabinoid system against cell toxicity, we hypothesized that treatment with an anandamide hydrolysis inhibitor, URB597, or with a phytocannabinoid, cannabidiol (CBD), protects against cocaine toxicity. URB597 (1.0 mg/kg) abolished cocaine-induced seizure, yet it did not protect against acute liver injury. Using confocal liver intravital microscopy, we observed that CBD (30 mg/kg) reduced acute liver inflammation and damage induced by cocaine and prevented associated seizure. Additionally, we showed that previous liver damage induced by another hepatotoxic drug (acetaminophen) increased seizure and lethality induced by cocaine intoxication, linking hepatotoxicity to seizure dynamics. These findings suggest that activation of cannabinoid system may have protective actions on both liver and brain induced by cocaine, minimizing inflammatory injury promoted by cocaine, supporting its further clinical application in the treatment of cocaine abuse.
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Analysis in conditional cannabinoid 1 receptor-knockout mice reveals neuronal subpopulation-specific effects on epileptogenesis in the kindling paradigm. Neurobiol Dis 2015; 73:334-47. [DOI: 10.1016/j.nbd.2014.08.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 08/01/2014] [Indexed: 01/04/2023] Open
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dos Santos RG, Hallak JEC, Leite JP, Zuardi AW, Crippa JAS. Phytocannabinoids and epilepsy. J Clin Pharm Ther 2014; 40:135-43. [PMID: 25475762 DOI: 10.1111/jcpt.12235] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/06/2014] [Indexed: 12/30/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Antiepileptic drugs often produce serious adverse effects, and many patients do not respond to them properly. Phytocannabinoids produce anticonvulsant effects in preclinical and preliminary human studies, and appear to produce fewer adverse effects than available antiepileptic drugs. The present review summarizes studies on the anticonvulsant properties of phytocannabinoids. METHODS Literature search using the PubMed database to identify studies on phytocannabinoids and epilepsy. RESULTS AND DISCUSSION Preclinical studies suggest that phytocannabinoids, especially cannabidiol and cannabidivarin, have potent anticonvulsant effects which are mediated by the endocannabinoid system. Human studies are limited in number and quality, but suggest that cannabidiol has anticonvulsant effects in adult and infantile epilepsy and is well tolerated after prolonged administration. WHAT IS NEW AND CONCLUSION Phytocannabinoids produce anticonvulsant effects through the endocannabinoid system, with few adverse effects. Cannabidiol and cannabidivarin should be tested in randomized, controlled clinical trials, especially in infantile epileptic syndromes.
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Affiliation(s)
- R G dos Santos
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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55
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Szaflarski JP, Bebin EM. Cannabis, cannabidiol, and epilepsy--from receptors to clinical response. Epilepsy Behav 2014; 41:277-82. [PMID: 25282526 DOI: 10.1016/j.yebeh.2014.08.135] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Accepted: 08/26/2014] [Indexed: 10/24/2022]
Abstract
Recreational cannabis use in adults with epilepsy is widespread. The use of cannabis for medicinal purposes is also becoming more prevalent. For this purpose, various preparations of cannabis of varying strengths and content are being used. The recent changes in the legal environment have improved the availability of products with high cannabidiol (CBD) and low tetrahydrocannabinol (THC) concentrations. There is some anecdotal evidence of their potential efficacy, but the mechanisms of such action are not entirely clear. Some suspect an existence of synergy or "entourage effect" between CBD and THC. There is strong evidence that THC acts via the cannabinoid receptor CB1. The mechanism of action of CBD is less clear but is likely polypharmacological. The scientific data support the role of the endocannabinoid system in seizure generation, maintenance, and control in animal models of epilepsy. There are clear data for the negative effects of cannabis on the developing and mature brain though these effects appear to be relatively mild in most cases. Further data from well-designed studies are needed regarding short- and long-term efficacy and side effects of CBD or high-CBD/low-THC products for the treatment of seizures and epilepsy in children and adults.
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Affiliation(s)
- Jerzy P Szaflarski
- UAB Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - E Martina Bebin
- UAB Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
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Post-status epilepticus treatment with the cannabinoid agonist WIN 55,212-2 prevents chronic epileptic hippocampal damage in rats. Neurobiol Dis 2014; 73:356-65. [PMID: 25447228 DOI: 10.1016/j.nbd.2014.10.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/13/2014] [Accepted: 10/17/2014] [Indexed: 12/12/2022] Open
Abstract
Repeated seizures are often associated with development of refractory chronic epilepsy, the most common form of which is temporal lobe epilepsy. G-protein-coupled cannabinoid receptors (CB1 and CB2 receptors) regulate neuronal excitability and have been shown to mediate acute anticonvulsant effects of cannabinoids in animal models. However, the potential of cannabinoids to prevent chronic neuronal damage and development of epilepsy remains unexplored. We hypothesized that treatment with a CB receptor agonist after an episode of status epilepticus--but before development of spontaneous recurrent seizures--might prevent the development of functional changes that lead to chronic epilepsy. Using the rat pilocarpine model, a therapeutic approach was simulated by administering the CB agonist, WIN 55,212-2 after an episode of status epilepticus. Epileptic behavior was monitored during development of spontaneous recurrent seizures for up to 6 months. Histology, neurochemistry, redox status and NMDA receptor subunit expression were assessed at 6 months after pilocarpine-induced seizures. Sub-acute treatment with WIN 55,212-2 (for 15 days starting 24h after PILO injection) dramatically attenuated the severity, duration and frequency of spontaneous recurrent seizures. Further, in contrast to vehicle-treated animals, hippocampi from WIN 55,212-2-treated animals showed: normal thiol redox state, normal NR2A and NR2B subunit expression, preservation of GABAergic neurons and prevention of abnormal proliferation of GABAergic progenitors. This study shows for the first time that, after a known inciting event, treatment with a compound targeting CB receptors has the potential to prevent the epileptogenic events that result in chronic epileptic damage.
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57
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Yan XJ, Chen SL. Response to Letter to the Editor. Pain 2014; 155:2205. [DOI: 10.1016/j.pain.2014.08.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 08/21/2014] [Accepted: 08/26/2014] [Indexed: 12/01/2022]
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Endocannabinoid signals in the developmental programming of delayed-onset neuropsychiatric and metabolic illnesses. Biochem Soc Trans 2014; 41:1569-76. [PMID: 24256256 DOI: 10.1042/bst20130117] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
It is increasingly recognized that maternal exposure to metabolic (nutritional) stimuli, infections, illicit or prescription drugs and environmental stressors during pregnancy can predispose affected offspring to developing devastating postnatal illnesses. If detrimental maternal stimuli coincide with critical periods of tissue production and organogenesis then they can permanently derail key cellular differentiation programs. Maternal programming can thus either provoke developmental failure directly ('direct hit') or introduce latent developmental errors that enable otherwise sub-threshold secondary stressors to manifest as disease ('double hit') postnatally. Accumulating evidence suggests that nervous system development is tightly controlled by maternal metabolic stimuli, and whose synaptic wiring and integrative capacity are adversely affected by dietary and hormonal challenges, infections or episodes of illicit drug use. Endocannabinoids, a family of signal lipids derived from polyunsaturated fatty acids, have been implicated in neuronal fate determination, the control of axonal growth, synaptogenesis and synaptic neurotransmission. Therefore the continuum and interdependence of endocannabinoid actions during the formation and function of synapses together with dynamic changes in focal and circulating endocannabinoid levels upon maternal nutritional imbalance suggest that endocannabinoids can execute the 'reprogramming' of specific neuronal networks. In the present paper, we review molecular evidence suggesting that maternal nutrition and metabolism during pregnancy can affect the formation and function of the hippocampus and hypothalamus by altering endocannabinoid signalling such that neuropsychiatric diseases and obesity respectively ensue in affected offspring. Moreover, we propose that the placenta, fetal adipose and nervous tissues interact via endocannabinoid signals. Thus endocannabinoids are hypothesized to act as a molecular substrate of maternal programming.
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Multifractal analysis of information processing in hippocampal neural ensembles during working memory under Δ⁹-tetrahydrocannabinol administration. J Neurosci Methods 2014; 244:136-53. [PMID: 25086297 DOI: 10.1016/j.jneumeth.2014.07.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 06/06/2014] [Accepted: 07/16/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND Multifractal analysis quantifies the time-scale-invariant properties in data by describing the structure of variability over time. By applying this analysis to hippocampal interspike interval sequences recorded during performance of a working memory task, a measure of long-range temporal correlations and multifractal dynamics can reveal single neuron correlates of information processing. NEW METHOD Wavelet leaders-based multifractal analysis (WLMA) was applied to hippocampal interspike intervals recorded during a working memory task. WLMA can be used to identify neurons likely to exhibit information processing relevant to operation of brain-computer interfaces and nonlinear neuronal models. RESULTS Neurons involved in memory processing ("Functional Cell Types" or FCTs) showed a greater degree of multifractal firing properties than neurons without task-relevant firing characteristics. In addition, previously unidentified FCTs were revealed because multifractal analysis suggested further functional classification. The cannabinoid type-1 receptor (CB1R) partial agonist, tetrahydrocannabinol (THC), selectively reduced multifractal dynamics in FCT neurons compared to non-FCT neurons. COMPARISON WITH EXISTING METHODS WLMA is an objective tool for quantifying the memory-correlated complexity represented by FCTs that reveals additional information compared to classification of FCTs using traditional z-scores to identify neuronal correlates of behavioral events. CONCLUSION z-Score-based FCT classification provides limited information about the dynamical range of neuronal activity characterized by WLMA. Increased complexity, as measured with multifractal analysis, may be a marker of functional involvement in memory processing. The level of multifractal attributes can be used to differentially emphasize neural signals to improve computational models and algorithms underlying brain-computer interfaces.
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Commentary on Kaushik et al.: Prostaglandin D2 is crucial for seizure suppression and postictal sleep. Novel evidence supporting a role for prostanoid receptors in seizure control. Exp Neurol 2014; 257:157-61. [DOI: 10.1016/j.expneurol.2014.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/26/2014] [Accepted: 05/02/2014] [Indexed: 11/22/2022]
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Abstract
Charlotte, a little girl with SCN1A-confirmed Dravet syndrome, was recently featured in a special that aired on CNN. Through exhaustive personal research and assistance from a Colorado-based medical marijuana group (Realm of Caring), Charlotte's mother started adjunctive therapy with a high concentration cannabidiol/Δ(9) -tetrahydrocannabinol (CBD:THC) strain of cannabis, now known as Charlotte's Web. This extract, slowly titrated over weeks and given in conjunction with her existing antiepileptic drug regimen, reduced Charlotte's seizure frequency from nearly 50 convulsive seizures per day to now 2-3 nocturnal convulsions per month. This effect has persisted for the last 20 months, and Charlotte has been successfully weaned from her other antiepileptic drugs. We briefly review some of the history, preclinical and clinical data, and controversies surrounding the use of medical marijuana for the treatment of epilepsy, and make a case that the desire to isolate and treat with pharmaceutical grade compounds from cannabis (specifically CBD) may be inferior to therapy with whole plant extracts. Much more needs to be learned about the mechanisms of antiepileptic activity of the phytocannabinoids and other constituents of Cannabis sativa.
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Affiliation(s)
- Edward Maa
- Comprehensive Epilepsy Program Denver Health and Hospitals, Denver, Colorado, U.S.A; Department of Neurology, University of Colorado, Denver, Colorado, U.S.A
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62
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Cilio MR, Thiele EA, Devinsky O. The case for assessing cannabidiol in epilepsy. Epilepsia 2014; 55:787-90. [PMID: 24854434 DOI: 10.1111/epi.12635] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2014] [Indexed: 11/30/2022]
Abstract
Intractable epilepsies have an extraordinary impact on cognitive and behavioral function and quality of life, and the treatment of seizures represents a challenge and a unique opportunity. Over the past few years, considerable attention has focused on cannabidiol (CBD), the major nonpsychotropic compound of Cannabis sativa. Basic research studies have provided strong evidence for safety and anticonvulsant properties of CBD. However, the lack of pure, pharmacologically active compounds and legal restrictions have prevented clinical research and confined data on efficacy and safety to anecdotal reports. Pure CBD appears to be an ideal candidate among phytocannabinoids as a therapy for treatment-resistant epilepsy. A first step in this direction is to systematically investigate the safety, pharmacokinetics, and interactions of CBD with other antiepileptic drugs and obtain an initial signal regarding efficacy at different dosages. These data can then be used to plan double-blinded placebo-controlled efficacy trials. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
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Affiliation(s)
- Maria Roberta Cilio
- Departments of Neurology and Pediatrics, University of California San Francisco, San Francisco, California, U.S.A
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63
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Feng CC, Yan XJ, Chen X, Wang EM, Liu Q, Zhang LY, Chen J, Fang JY, Chen SL. Vagal anandamide signaling via cannabinoid receptor 1 contributes to luminal 5-HT modulation of visceral nociception in rats. Pain 2014; 155:1591-1604. [PMID: 24813296 DOI: 10.1016/j.pain.2014.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 04/24/2014] [Accepted: 05/02/2014] [Indexed: 12/19/2022]
Abstract
Serotonin (5-HT) plays pivotal roles in the pathogenesis of postinfectious irritable bowel syndrome (PI-IBS), and luminal 5-HT time-dependently modulates visceral nociception. We found that duodenal biopsies from PI-IBS patients exhibited increased 5-HT and decreased anandamide levels and that decreased anandamide was associated with abdominal pain severity, indicating a link between 5-HT and endocannabinoid signaling pathways in PI-IBS. To understand this, we investigated the role of endocannabinoids in 5-HT modulation of visceral nociception in a rat model. Acute intraduodenally applied 5-HT attenuated the visceromotor response (VMR) to colorectal distention, and this was reversed by the cannabinoid receptor 1 (CB1) antagonist AM251. Duodenal anandamide (but not 2-arachidonoylglycerol) content was greatly increased after luminal 5-HT treatment. This effect was abrogated by the 5-HT 3 receptor (5-HT3R) antagonist granisetron, which was luminally delivered to preferentially target vagal terminals. Chemical denervation of vagal afferents blocked 5-HT-evoked antinociception and anandamide release. Chronic luminal 5-HT exposure for 5 days increased baseline VMR and VMR post-5-HT (days 4 and 5). Duodenal levels of anandamide and N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD, the anandamide-synthesizing enzyme) protein gradually declined from day 1 to 5. The time-dependent effects of 5-HT were abolished by daily granisetron pretreatment. Daily pretreatment with CB1 agonists or anandamide from day 3 attenuated 5-HT-induced hyperalgesia. These data suggest that vagal 5-HT3R-mediated duodenal anandamide release contributes to acute luminal 5-HT-induced antinociception via CB1 signaling, whereas decreased anandamide is associated with hyperalgesia upon chronic 5-HT treatment. Further understanding of peripheral vagal anandamide signaling may provide insights into the mechanisms underlying 5-HT-related IBS.
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Affiliation(s)
- Chen-Chen Feng
- Department of Gastroenterology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, 145 Middle Shandong Road, Shanghai, China Department of pharmaceutics, Key Laboratory of Smart Drug Delivery, Ministry of Education & PLA, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai, China
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Vilela LR, Medeiros DC, de Oliveira ACP, Moraes MF, Moreira FA. Anticonvulsant effects of N-arachidonoyl-serotonin, a dual fatty acid amide hydrolase enzyme and transient receptor potential vanilloid type-1 (TRPV1) channel blocker, on experimental seizures: the roles of cannabinoid CB1 receptors and TRPV1 channels. Basic Clin Pharmacol Toxicol 2014; 115:330-4. [PMID: 24674273 DOI: 10.1111/bcpt.12232] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/04/2014] [Indexed: 01/21/2023]
Abstract
Selective blockade of anandamide hydrolysis, through the inhibition of the FAAH enzyme, has anticonvulsant effects, which are mediated by CB1 receptors. Anandamide, however, also activates TRPV1 channels, generally with an opposite outcome on neuronal modulation. Thus, we suggested that the dual FAAH and TRPV1 blockade with N-arachidonoyl-serotonin (AA-5-HT) would be efficacious in inhibiting pentylenetetrazole (PTZ)-induced seizures in mice. We also investigated the contribution of CB1 activation and TRPV1 blockade to the overt effect of AA-5-HT. In the first experiment, injection of AA-5-HT (0.3-3.0 mg/kg) delayed the onset and reduced the duration of PTZ (60 mg)-induced seizures in mice. These effects were reversed by pre-treatment with the CB1 antagonist, AM251 (1.0-3.0 mg/kg). Finally, we observed that administration of the selective TRPV1 antagonist, SB366791 (0.1-1 mg/kg), did not entirely mimic AA-5-HT effects. In conclusion, AA-5-HT alleviates seizures in mice, an effect inhibited by CB1 antagonism, but not completely mimicked by TRPV1 blockage, indicating that the overall effect of AA-5-HT seems to depend mainly on CB1 receptors. This may represent a new strategy for the development of drugs against seizures, epilepsies and related syndromes.
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Affiliation(s)
- Luciano R Vilela
- Graduate School in Neuroscience, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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65
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Younts TJ, Castillo PE. Endogenous cannabinoid signaling at inhibitory interneurons. Curr Opin Neurobiol 2013; 26:42-50. [PMID: 24650503 DOI: 10.1016/j.conb.2013.12.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 12/02/2013] [Accepted: 12/04/2013] [Indexed: 11/15/2022]
Abstract
Significant progress has been made in our understanding of how endogenous cannabinoids (eCBs) signal at excitatory and inhibitory synapses in the central nervous system (CNS). This review discusses how eCBs regulate inhibitory interneurons, their synapses, and the networks in which they are embedded. eCB signaling plays a pivotal role in brain physiology by means of their synaptic signal transduction, spatiotemporal signaling profile, routing of information through inhibitory microcircuits, and experience-dependent plasticity. Understanding the normal processes underlying eCB signaling is beginning to shed light on how their dysregulation contributes to disease.
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Affiliation(s)
- Thomas J Younts
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
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66
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Liedhegner ES, Sasman A, Hillard CJ. Brain region-specific changes in N-acylethanolamine contents with time of day. J Neurochem 2013; 128:491-506. [PMID: 24138639 DOI: 10.1111/jnc.12495] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/06/2013] [Accepted: 10/04/2013] [Indexed: 11/28/2022]
Abstract
The N-acylethanolamines (NAEs) exert important behavioral, physiological, and immunological effects through actions at cannabinoid and other receptors. We measured concentrations of three NAEs, the Km and Vmax for fatty acid amide hydrolysis (FAAH), FAAH protein and FAAH mRNA in prefrontal cortex, hippocampus, hypothalamus, amygdala, striatum, and cerebellum at 4 h intervals, starting at 03:00. Significant differences in N-arachidonylethanolamine contents among the times examined occur in the prefrontal cortex (PFC), hippocampus, hypothalamus, and striatum. N-Oleoylethanolamine concentrations exhibit large fluctuations over the day in the cerebellum, including a threefold decrease between 19:00 and 23:00. N-Palmitoylethanolamine and N-oleoylethanolamine were significantly, positively correlated in all regions examined except the hypothalamus. FAAH Km values are significantly affected by time of day in PFC, hippocampus and amygdala and FAAH Vmax values are significantly affected in PFC, hippocampus and cerebellum. However, correlational data indicate that FAAH does not play a primary role in the circadian regulation of the NAE concentrations. FAAH protein expression is not significantly different among the harvest times in any brain region examined. Concentrations of 2-arachidonoylglycerol are significantly affected by time of harvest in the striatum and cerebellum, but not in other brain regions. Together, these data indicate that the NAEs exhibit diverse patterns of change with time of day that are likely the result of alterations in biosynthesis, and support the hypothesis that N-arachidonylethanolamine is a tonic activator of cannabinoid receptor signaling.
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Affiliation(s)
- Elizabeth Sabens Liedhegner
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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67
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CA1 pyramidal cell theta-burst firing triggers endocannabinoid-mediated long-term depression at both somatic and dendritic inhibitory synapses. J Neurosci 2013; 33:13743-57. [PMID: 23966696 DOI: 10.1523/jneurosci.0817-13.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Endocannabinoids (eCBs) are retrograde lipid messengers that, by targeting presynaptic type 1 cannabinoid receptors (CB1Rs), mediate short- and long-term synaptic depression of neurotransmitter release throughout the brain. Short-term depression is typically triggered by postsynaptic, depolarization-induced calcium rises, whereas long-term depression is induced by synaptic activation of Gq/11 protein-coupled receptors. Here we report that a physiologically relevant pattern of postsynaptic activity, in the form of theta-burst firing (TBF) of hippocampal CA1 pyramidal neurons, can trigger long-term depression of inhibitory transmission (iLTD) in rat hippocampal slices. Paired recordings between CA1 interneurons and pyramidal cells, followed by post hoc morphological reconstructions of the interneurons' axon, revealed that somatic and dendritic inhibitory synaptic inputs equally expressed TBF-induced iLTD. Simultaneous recordings from neighboring pyramidal cells demonstrated that eCB signaling triggered by TBF was highly restricted to only a single, active cell. Furthermore, pairing submaximal endogenous activation of metabotropic glutamate or muscarinic acetylcholine receptors with submaximal TBF unmasked associative iLTD. Although CB1Rs are also expressed at Schaffer-collateral excitatory terminals, long-term plasticity under various recording conditions was spared at these synapses. Consistent with this observation, TBF also shifted the balance of excitation and inhibition in favor of excitatory throughput, thereby altering information flow through the CA1 circuit. Given the near ubiquity of burst-firing activity patterns and CB1R expression in the brain, the properties described here may be a general means by which neurons fine tune the strength of their inputs in a cell-wide and cell-specific manner.
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68
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de Havenon A, Chin B, Thomas KC, Afra P. The secret "spice": an undetectable toxic cause of seizure. Neurohospitalist 2013; 1:182-6. [PMID: 23983854 DOI: 10.1177/1941874411417977] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Neurologists and emergency department physicians are frequently involved in the comprehensive evaluation of a first generalized seizure. An important aspect of this evaluation is a detailed history which can identify a provoked seizure secondary to drug toxicity and hence avoid unnecessary treatment with antiepileptic drugs. "Spice" is an umbrella term for a variety of synthetic cannabinoid products whose inhalation has been associated with an increasing number of toxic side effects resulting in emergency department visits. These side effects (including psychosis, tachyarrhythmia, and seizures) are not typically seen with marijuana (Cannabis sativa) use. We report 2 patients with no prior history of neurological disease that experienced their first generalized tonic-clonic seizure after smoking Spice. The mechanism behind the possible proconvulsant effect of synthetic cannabinoids is not known, but it may be due to their effects at the cannabinoid receptor CB1. Although the US Drug Enforcement Administration placed 5 synthetic cannabinoids into schedule 1 for a 12-month period beginning March 2011, new Spice products containing different synthetic cannabinoids continue to emerge. Because synthetic cannabinoids are not detectable on commercial drug screens it is important that neurologists and emergency department physicians consider Spice inhalation in their differential diagnosis of a first generalized seizure.
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Affiliation(s)
- Adam de Havenon
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT, USA
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69
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The role of potassium BK channels in anticonvulsant effect of cannabidiol in pentylenetetrazole and maximal electroshock models of seizure in mice. Epilepsy Behav 2013; 28:1-7. [PMID: 23644464 DOI: 10.1016/j.yebeh.2013.03.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 03/02/2013] [Accepted: 03/08/2013] [Indexed: 11/22/2022]
Abstract
Cannabidiol is a nonpsychoactive member of phytocannabinoids that produces various pharmacological effects that are not mediated through putative CB1/CB2 cannabinoid receptors and their related effectors. In this study, we examined the effect of the i.c.v. administration of potassium BK channel blocker paxilline alone and in combination with cannabidiol in protection against pentylenetetrazol (PTZ)- and maximal electroshock (MES)-induced seizure in mice. In the PTZ-induced seizure model, i.c.v. administration of cannabidiol caused a significant increase in seizure threshold compared with the control group. Moreover, while i.c.v. administration of various doses of paxilline did not produce significant change in the PTZ-induced seizure threshold in mice, coadministration of cannabidiol and paxilline attenuated the antiseizure effect of cannabidiol in PTZ-induced tonic seizures. In the MES model of seizure, both cannabidiol and paxilline per se produced significant increase in percent protection against electroshock-induced seizure. However, coadministration of cannabidiol and paxilline did not produce significant interaction in their antiseizure effect in the MES test. The results of the present study showed a protective effect of cannabidiol in both PTZ and MES models of seizure. These results suggested a BK channel-mediated antiseizure action of cannabidiol in PTZ model of seizure. However, such an interaction might not exist in MES-induced convulsion.
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Xapelli S, Agasse F, Sardà-Arroyo L, Bernardino L, Santos T, Ribeiro FF, Valero J, Bragança J, Schitine C, de Melo Reis RA, Sebastião AM, Malva JO. Activation of type 1 cannabinoid receptor (CB1R) promotes neurogenesis in murine subventricular zone cell cultures. PLoS One 2013; 8:e63529. [PMID: 23704915 PMCID: PMC3660454 DOI: 10.1371/journal.pone.0063529] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 04/06/2013] [Indexed: 11/18/2022] Open
Abstract
The endocannabinoid system has been implicated in the modulation of adult neurogenesis. Here, we describe the effect of type 1 cannabinoid receptor (CB1R) activation on self-renewal, proliferation and neuronal differentiation in mouse neonatal subventricular zone (SVZ) stem/progenitor cell cultures. Expression of CB1R was detected in SVZ-derived immature cells (Nestin-positive), neurons and astrocytes. Stimulation of the CB1R by (R)-(+)-Methanandamide (R-m-AEA) increased self-renewal of SVZ cells, as assessed by counting the number of secondary neurospheres and the number of Sox2+/+ cell pairs, an effect blocked by Notch pathway inhibition. Moreover, R-m-AEA treatment for 48 h, increased proliferation as assessed by BrdU incorporation assay, an effect mediated by activation of MAPK-ERK and AKT pathways. Surprisingly, stimulation of CB1R by R-m-AEA also promoted neuronal differentiation (without affecting glial differentiation), at 7 days, as shown by counting the number of NeuN-positive neurons in the cultures. Moreover, by monitoring intracellular calcium concentrations ([Ca2+]i) in single cells following KCl and histamine stimuli, a method that allows the functional evaluation of neuronal differentiation, we observed an increase in neuronal-like cells. This proneurogenic effect was blocked when SVZ cells were co-incubated with R-m-AEA and the CB1R antagonist AM 251, for 7 days, thus indicating that this effect involves CB1R activation. In accordance with an effect on neuronal differentiation and maturation, R-m-AEA also increased neurite growth, as evaluated by quantifying and measuring the number of MAP2-positive processes. Taken together, these results demonstrate that CB1R activation induces proliferation, self-renewal and neuronal differentiation from mouse neonatal SVZ cell cultures.
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Affiliation(s)
- Sara Xapelli
- Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, University of Lisbon, Lisboa, Portugal
- Unit of Neurosciences, Instituto de Medicina Molecular, University of Lisbon, Lisboa, Portugal
| | - Fabienne Agasse
- Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
- * E-mail: (JOM); (FA)
| | - Laura Sardà-Arroyo
- Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
| | - Liliana Bernardino
- Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
- Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal
| | - Tiago Santos
- Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
| | - Filipa F. Ribeiro
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, University of Lisbon, Lisboa, Portugal
- Unit of Neurosciences, Instituto de Medicina Molecular, University of Lisbon, Lisboa, Portugal
| | - Jorge Valero
- Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
| | - José Bragança
- Institute for Biotechnology and Bioengineering, Centre for Molecular and Structural Biomedicine, University of Algarve, Faro, Portugal
| | - Clarissa Schitine
- Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
- Neurochemistry Laboratory, Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ricardo A. de Melo Reis
- Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
- Neurochemistry Laboratory, Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana M. Sebastião
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, University of Lisbon, Lisboa, Portugal
- Unit of Neurosciences, Instituto de Medicina Molecular, University of Lisbon, Lisboa, Portugal
| | - João O. Malva
- Center for Research on Environment, Genetics and Oncobiology (CIMAGO), Faculty of Medicine (polo 3), University of Coimbra, Coimbra, Portugal
- * E-mail: (JOM); (FA)
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Xapelli S, Agasse F, Sardà-Arroyo L, Bernardino L, Santos T, Ribeiro FF, Valero J, Bragança J, Schitine C, de Melo Reis RA, Sebastião AM, Malva JO. Activation of Type 1 Cannabinoid Receptor (CB1R) Promotes Neurogenesis in Murine Subventricular Zone Cell Cultures. PLoS One 2013; 8:e63529. [DOI: https:/doi.org/10.1371/journal.pone.0063529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023] Open
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Straiker A, Min KT, Mackie K. Fmr1 deletion enhances and ultimately desensitizes CB(1) signaling in autaptic hippocampal neurons. Neurobiol Dis 2013; 56:1-5. [PMID: 23578490 DOI: 10.1016/j.nbd.2013.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 03/30/2013] [Accepted: 04/02/2013] [Indexed: 12/13/2022] Open
Abstract
Fragile X Syndrome (FXS) is a heritable form of mental retardation caused by a non-coding trinucleotide expansion of the FMR1 gene leading to loss of expression of this RNA binding protein. Mutations in this gene are strongly linked to enhanced Group I metabotropic glutamate receptor (mGluR) signaling. A recent report found that mGluR5-dependent endogenous cannabinoid signaling is enhanced in hippocampal slices from fmr1 knockout mice, suggesting a link between FXS and cannabinoid signaling. Alterations in cannabinoid signaling have an impact on learning and memory and may therefore be linked to some aspects of the FXS phenotype. We have used autaptic hippocampal neurons cultured from fmr1 knockout mice to further explore the interaction between endocannabinoid signaling and FMRP. These neurons express several robust forms of retrograde endocannabinoid signaling including depolarization induced suppression of excitation (DSE) and a metabotropic form (MSE) that results from Group I mGluR activation. We now report that young fmr1 neurons exhibit considerably enhanced DSE, likely via increased production of 2-AG, rather than enhanced mGluR-MSE. We find that depolarizations as brief as 50ms, which do not ordinarily produce DSE, routinely inhibited glutamate release. Furthermore, as neuronal cultures mature, CB1-receptor signaling strongly desensitizes. Our results suggest that loss of FMRP broadly affects the endocannabinoid signaling system, possibly through local 2-AG over production. Furthermore, the net effect of the loss of FMRP may actually be diminished cannabinoid signaling due to receptor desensitization as an adaptation to 2-AG overproduction.
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Affiliation(s)
- Alex Straiker
- Department of Psychological & Brain Sciences, Gill Center for Biomedical Sciences, Indiana University, Bloomington, IN 47405, USA.
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Vilela LR, Medeiros DC, Rezende GHS, de Oliveira ACP, Moraes MFD, Moreira FA. Effects of cannabinoids and endocannabinoid hydrolysis inhibition on pentylenetetrazole-induced seizure and electroencephalographic activity in rats. Epilepsy Res 2013; 104:195-202. [PMID: 23352737 DOI: 10.1016/j.eplepsyres.2012.11.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 10/29/2012] [Accepted: 11/15/2012] [Indexed: 01/08/2023]
Abstract
Cannabinoids and drugs that increase endocannabinoid levels inhibit neuronal excitability and restrain epileptic seizures through CB1 receptor activation. Nevertheless, the results have not been entirely consistent, since pro-convulsant effects have also been reported. The present study aimed to further investigate the effects of cannabinoid-related compounds on seizures induced by pentylenetetrazole (PTZ) in rats. Video-EEG recordings were used to determine both electrographic and behavioral thresholds to ictal activity. The animals received injections of WIN-55,212-2 (0.3-3 mg/kg, non-selective) or ACEA (1-4 mg/kg, CB1-selective), two synthetic cannabinoids, or URB-597 (0.3-3 mg/kg), an anandamide-hydrolysis inhibitor (FAAH enzyme inhibitor), followed by PTZ. Both WIN-55,212-2 (1 mg/kg) and ACEA (1-4 mg/kg) reduced the threshold for myoclonic seizures and enhanced epileptiform EEG activity, typical pro-convulsive effects. On the contrary, URB-597 (1 mg/kg) had an anti-convulsive effect, as it increased the threshold for the occurrence of minimal seizures and reduced EEG epileptiform activity. None of the drugs tested altered the tonic-clonic maximal seizure threshold. These data suggest that the effects of CB1 signaling upon seizure activity may depend on how this receptor is activated. Contrary to direct agonists, drugs that increase anandamide levels seem to promote an optimal tonus and represent a promising strategy for treating myoclonic seizures.
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Affiliation(s)
- Luciano R Vilela
- Graduate School in Neuroscience, Institute of Biological Sciences, Universidade Federal de Minas Gerais Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil
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Striatal GABAergic and cortical glutamatergic neurons mediate contrasting effects of cannabinoids on cortical network synchrony. Proc Natl Acad Sci U S A 2012; 110:719-24. [PMID: 23269835 DOI: 10.1073/pnas.1217144110] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Activation of type 1 cannabinoid receptors (CB1R) decreases GABA and glutamate release in cortical and subcortical regions, with complex outcomes on cortical network activity. To date there have been few attempts to disentangle the region- and cell-specific mechanisms underlying the effects of cannabinoids on cortical network activity in vivo. Here we addressed this issue by combining in vivo electrophysiological recordings with local and systemic pharmacological manipulations in conditional mutant mice lacking CB1R expression in different neuronal populations. First we report that cannabinoids induce hypersynchronous thalamocortical oscillations while decreasing the amplitude of faster cortical oscillations. Then we demonstrate that CB1R at striatonigral synapses (basal ganglia direct pathway) mediate the thalamocortical hypersynchrony, whereas activation of CB1R expressed in cortical glutamatergic neurons decreases cortical synchrony. Finally we show that activation of CB1 expressed in cortical glutamatergic neurons limits the cannabinoid-induced thalamocortical hypersynchrony. By reporting that CB1R activations in cortical and subcortical regions have contrasting effects on cortical synchrony, our study bridges the gap between cellular and in vivo network effects of cannabinoids. Incidentally, the thalamocortical hypersynchrony we report suggests a potential mechanism to explain the sensory "high" experienced during recreational consumption of marijuana.
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75
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Seizure exacerbation in two patients with focal epilepsy following marijuana cessation. Epilepsy Behav 2012; 25:563-6. [PMID: 23159379 DOI: 10.1016/j.yebeh.2012.09.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Revised: 09/16/2012] [Accepted: 09/17/2012] [Indexed: 11/20/2022]
Abstract
While animal models of epilepsy suggest that exogenous cannabinoids may have anticonvulsant properties, scant evidence exists for these compounds' efficacy in humans. Here, we report on two patients whose focal epilepsy was nearly controlled through regular outpatient marijuana use. Both stopped marijuana upon admission to our epilepsy monitoring unit (EMU) and developed a dramatic increase in seizure frequency documented by video-EEG telemetry. These seizures occurred in the absence of other provocative procedures, including changes to anticonvulsant medications. We review these cases and discuss mechanisms for the potentially anticonvulsant properties of cannabis, based on a review of the literature.
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Protective Effects of the CB1 Receptor Agonist WIN 55.212-2 during Development of Seizure Activity in the Brain in Models of Temporal Epilepsy in Vivo. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11055-012-9604-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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77
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Neuron to astrocyte communication via cannabinoid receptors is necessary for sustained epileptiform activity in rat hippocampus. PLoS One 2012; 7:e37320. [PMID: 22615976 PMCID: PMC3352897 DOI: 10.1371/journal.pone.0037320] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 04/18/2012] [Indexed: 11/19/2022] Open
Abstract
Astrocytes are integral functional components of synapses, regulating transmission and plasticity. They have also been implicated in the pathogenesis of epilepsy, although their precise roles have not been comprehensively characterized. Astrocytes integrate activity from neighboring synapses by responding to neuronally released neurotransmitters such as glutamate and ATP. Strong activation of astrocytes mediated by these neurotransmitters can promote seizure-like activity by initiating a positive feedback loop that induces excessive neuronal discharge. Recent work has demonstrated that astrocytes express cannabinoid 1 (CB1) receptors, which are sensitive to endocannabinoids released by nearby pyramidal cells. In this study, we tested whether this mechanism also contributes to epileptiform activity. In a model of 4-aminopyridine induced epileptic-like activity in hippocampal slice cultures, we show that pharmacological blockade of astrocyte CB1 receptors did not modify the initiation, but significantly reduced the maintenance of epileptiform discharge. When communication in astrocytic networks was disrupted by chelating astrocytic calcium, this CB1 receptor-mediated modulation of epileptiform activity was no longer observed. Thus, endocannabinoid signaling from neurons to astrocytes represents an additional significant factor in the maintenance of epileptiform activity in the hippocampus.
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78
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Ossola CA, Surkin PN, Pugnaloni A, Mohn CE, Elverdin JC, Fernandez-Solari J. Long-term treatment with methanandamide attenuates LPS-induced periodontitis in rats. Inflamm Res 2012; 61:941-8. [PMID: 22581275 DOI: 10.1007/s00011-012-0485-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/11/2012] [Accepted: 04/20/2012] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Evidence exists of the anti-inflammatory and immunological properties of endocannabinoids in various tissues; the aim of the present study was therefore to assess the effect of long-term treatment with the synthetic cannabinoid methanandamide (Meth-AEA) on the progression of periodontitis in rats. MATERIALS AND METHODS Periodontitis was induced by injecting LPS (1 mg/ml) into the gingiva around the neck of the first upper and lower molars, and into the inter-dental space between the first and second molars. This protocol was repeated for 6 weeks on days 1, 3, and 5 of each week. RESULTS Long-term treatment with topical Meth-AEA (500 ng/ml), applied daily to gingival tissue of rats induced with periodontitis, significantly diminished the alveolar bone loss, measured as the distance between the cemento-enamel junction and the alveolar crest, in both maxillary and mandibular first molars, compared to rats without treatment (P < 0.05). The treatment also reduced the production of some biological mediators of periodontal disease augmented by LPS, such as tumor necrosis factor alpha (from 119.4 ± 9.9 pg/mg protein to 75.1 ± 10.8, P < 0.05) and nitric oxide produced by inducible nitric oxide synthase (from 507.7 ± 107.1 pmol/min/mg protein to 163.1 ± 53.9, P < 0.01). CONCLUSION These results demonstrate the beneficial effects of treatment with Meth-AEA on gingival tissue of rats with periodontitis.
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Affiliation(s)
- Cesar A Ossola
- Laboratory of Oral Physiology, Department of Physiology, Dental School, University of Buenos Aires, Marcelo T. de Alvear 2142, 1122, Buenos Aires, Argentina
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Messer RD, Levine ES. Epileptiform activity in the CA1 region of the hippocampus becomes refractory to attenuation by cannabinoids in part because of endogenous γ-aminobutyric acid type B receptor activity. J Neurosci Res 2012; 90:1454-63. [PMID: 22388975 DOI: 10.1002/jnr.23027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 11/30/2011] [Accepted: 12/12/2011] [Indexed: 12/18/2022]
Abstract
The anticonvulsant properties of marijuana have been known for centuries. The recently characterized endogenous cannabinoid system thus represents a promising target for novel anticonvulsant agents; however, administration of exogenous cannabinoids has shown mixed results in both human epilepsy and animal models. The ability of cannabinoids to attenuate release of both excitatory and inhibitory neurotransmitters may explain the variable effects of cannabinoids in different models of epilepsy, but this has not been well explored. Using acute mouse brain slices, we monitored field potentials in the CA1 region of the hippocampus to characterize systematically the effects of the cannabinoid agonist WIN55212-2 (WIN) on evoked basal and epileptiform activity. WIN, acting presynaptically, significantly reduced the amplitude and slope of basal field excitatory postsynaptic potentials as well as stimulus-evoked epileptiform responses induced by omission of magnesium from the extracellular solution. In contrast, the combination of omission of magnesium plus elevation of potassium induced an epileptiform response that was refractory to attenuation by WIN. The effect of WIN in this model was partially restored by blocking γ-aminobutyric acid type B (GABA(B) ), but not GABA(A) , receptors. Subtle differences in models of epileptiform activity can profoundly alter the efficacy of cannabinoids. Endogenous GABA(B) receptor activation played a role in the decreased cannabinoid sensitivity observed for epileptiform activity induced by omission of magnesium plus elevation of potassium. These results suggest that interplay between presynaptic G protein-coupled receptors with overlapping downstream targets may underlie the variable efficacy of cannabinoids in different models of epilepsy.
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Affiliation(s)
- Ricka D Messer
- Department of Neuroscience, University of Connecticut Health Center, Farmington,CT 06030, USA
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80
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Languille S, Blanc S, Blin O, Canale CI, Dal-Pan A, Devau G, Dhenain M, Dorieux O, Epelbaum J, Gomez D, Hardy I, Henry PY, Irving EA, Marchal J, Mestre-Francés N, Perret M, Picq JL, Pifferi F, Rahman A, Schenker E, Terrien J, Théry M, Verdier JM, Aujard F. The grey mouse lemur: a non-human primate model for ageing studies. Ageing Res Rev 2012; 11:150-62. [PMID: 21802530 DOI: 10.1016/j.arr.2011.07.001] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 07/04/2011] [Accepted: 07/08/2011] [Indexed: 01/27/2023]
Abstract
The use of non-human primate models is required to understand the ageing process and evaluate new therapies against age-associated pathologies. The present article summarizes all the contributions of the grey mouse lemur Microcebus murinus, a small nocturnal prosimian primate, to the understanding of the mechanisms of ageing. Results from studies of both healthy and pathological ageing research on the grey mouse lemur demonstrated that this animal is a unique model to study age-dependent changes in endocrine systems, biological rhythms, thermoregulation, sensorial, cerebral and cognitive functions.
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Karlócai MR, Tóth K, Watanabe M, Ledent C, Juhász G, Freund TF, Maglóczky Z. Redistribution of CB1 cannabinoid receptors in the acute and chronic phases of pilocarpine-induced epilepsy. PLoS One 2011; 6:e27196. [PMID: 22076136 PMCID: PMC3208595 DOI: 10.1371/journal.pone.0027196] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 10/12/2011] [Indexed: 01/29/2023] Open
Abstract
The endocannabinoid system plays a central role in retrograde synaptic communication and may control the spread of activity in an epileptic network. Using the pilocarpine model of temporal lobe epilepsy we examined the expression pattern of the Type 1 cannabinoid receptor (CB1-R) in the hippocampi of CD1 mice at survival times of 2 hours, 1 day, 3 days and 2 months (acute, latent and chronic phases). Based on the behavioral signs of the acute seizures, animals were classified as "weakly" or "strongly" epileptic using the modified Racine scale. Mice of the weak group had mild seizures, whereas seizures in the strong group were frequent with intense motor symptoms and the majority of these animals developed sclerosis in the chronic phase. In control samples the most intense staining of CB1-R-positive fibers was found in the molecular layer of the dentate gyrus and in str. pyramidale of the cornu Ammonis. In weak animals no significant changes were seen at any survival time compared to controls. In strong animals, however, in the acute phase, a massive reduction in CB1-R-stained terminals occurred in the hippocampus. In the latent phase CB1-R immunoreactivity gradually recovered. In the chronic phase, CB1-immunostaining in sclerotic samples was stronger throughout the hippocampus. Quantitative electron microscopic analysis showed an increase in the number of CB1-R-positive terminals in the dentate gyrus. Moreover, the number of immunogold particles significantly increased in GABAergic terminals. Our results suggest a proconvulsive downregulation of CB1 receptors in the acute phase most probably due to receptor internalization, followed by compensatory upregulation and sprouting in the chronic phase of epilepsy. In conclusion, the changes in CB1 receptor expression pattern revealed in this study are associated with the severity of hippocampal injury initiated by acute seizures that ultimately leads to sclerosis in the vulnerable regions in the chronic phase.
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Affiliation(s)
- Mária R Karlócai
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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Noriega-Ortega BR, Armienta-Aldana E, Cervantes-Pompa JÁ, Armienta-Aldana E, Hernández-Ruíz E, Chaparro-Huerta V, Bravo-Cuellar A, Beas-Zárate C. GABA and Dopamine Release from Different Brain Regions in Mice with Chronic Exposure to Organophosphate Methamidophos. J Toxicol Pathol 2011; 24:163-8. [PMID: 22272056 PMCID: PMC3234592 DOI: 10.1293/tox.24.163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 05/16/2011] [Indexed: 12/03/2022] Open
Abstract
Organophosphates such as methamidophos, usually used in the agricultural field, have
harmful effects on humans. Exposures to insecticides has been associated with many
disorders, including damage to the central and peripheral nervous system. Chronic exposure
to organophosphates may lead to persistent neurological and neurobehavioral effects. This
study was conducted to determine the effect of methamidophos on [3H]-dopamine
(DA) and gamma aminobutyric acid (GABA) release from different brain regions after chronic
exposure to it for 3, 6 or 9 months. After a six-month methamidophos treatment, the mice
showed high susceptibility to convulsive seizures and a reduction in stimulated gamma
aminobutyric acid release from the cerebral cortex and hippocampal slices, whereas
stimulated (DA) release was slightly decreased from the striatum after three months of
methamidophos exposure. The results indicate changes in gamma aminobutyric acid and
dopamine neurotransmission, suggesting a specific neuronal damage.
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83
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L-type calcium channel mediates anticonvulsant effect of cannabinoids in acute and chronic murine models of seizure. Neurochem Res 2011; 37:279-87. [PMID: 21928146 DOI: 10.1007/s11064-011-0607-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/06/2011] [Accepted: 09/10/2011] [Indexed: 10/17/2022]
Abstract
The anticonvulsant activities of cannabinoid compounds have been shown in various models of seizure and epilepsy. At least, part of antiseizure effects of cannabinoid compounds is mediated through calcium (Ca(2+)) channels. The L-type Ca(2+) channels have been shown to be important in various epilepsy models. However, there is no data regarding the role of L-type Ca(2+) channels in protective action of cannabinoids on acute and chronic models of seizure. In this study, the effects of cannabinoid compounds and L-type Ca(2+) channels blockers, either alone or in combination were investigated using acute model of pentylenetetrazole (PTZ)-induced seizure in mice and chronic model electrical kindling of amygdala in rats. Pretreatment of mice with both cannabinoid CB1 receptor agonist arachidonyl-2'-chloroethylamide (ACEA) and endocannabinoid degradating enzyme inhibitor cyclohexylcarbamic acid 3'-carbamoyl-biphenyl-3-yl ester (URB597) produced a protective effect against PTZ-induced seizure. Administration of various doses of the two L-type Ca(2+) channel blockers verapamil and diltiazem did not alter PTZ-induced seizure threshold. However, co-administration of verapamil and either ACEA or URB597 attenuated the protective effect of cannabinoid compounds against PTZ-induced seizure. Also, pretreatment of mice with diltiazem blocked the anticonvulsant activity of both ACEA and URB597. Moreover, (R)-(+)-[2,3-dihydro-5-methyl-3[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl) methanone mesylate (WIN55,212-2), the non-selective cannabinoid CB1 and CB2 receptor agonist showed anticonvulsant effect in amygdala-kindled rats. However, co-administration of WIN55,212-2 and verapamil attenuated the protective properties of WIN55,212-2. Our results showed that the anticonvulsant activity of cannabinoid compounds is mediated, at least in part, by L-type Ca(2+) channels in these two models of convulsion and epilepsy.
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84
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Zanettini C, Panlilio LV, Alicki M, Goldberg SR, Haller J, Yasar S. Effects of endocannabinoid system modulation on cognitive and emotional behavior. Front Behav Neurosci 2011; 5:57. [PMID: 21949506 PMCID: PMC3171696 DOI: 10.3389/fnbeh.2011.00057] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 08/21/2011] [Indexed: 11/24/2022] Open
Abstract
Cannabis has long been known to produce cognitive and emotional effects. Research has shown that cannabinoid drugs produce these effects by driving the brain’s endogenous cannabinoid system and that this system plays a modulatory role in many cognitive and emotional processes. This review focuses on the effects of endocannabinoid system modulation in animal models of cognition (learning and memory) and emotion (anxiety and depression). We review studies in which natural or synthetic cannabinoid agonists were administered to directly stimulate cannabinoid receptors or, conversely, where cannabinoid antagonists were administered to inhibit the activity of cannabinoid receptors. In addition, studies are reviewed that involved genetic disruption of cannabinoid receptors or genetic or pharmacological manipulation of the endocannabinoid-degrading enzyme, fatty acid amide hydrolase (FAAH). Endocannabinoids affect the function of many neurotransmitter systems, some of which play opposing roles. The diversity of cannabinoid roles and the complexity of task-dependent activation of neuronal circuits may lead to the effects of endocannabinoid system modulation being strongly dependent on environmental conditions. Recent findings are reviewed that raise the possibility that endocannabinoid signaling may change the impact of environmental influences on emotional and cognitive behavior rather than selectively affecting any specific behavior.
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Affiliation(s)
- Claudio Zanettini
- Department of Health and Human Services, Preclinical Pharmacology Section, Behavioral Neurosciences Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health Baltimore, MD, USA
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85
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Hill AJ, Williams CM, Whalley BJ, Stephens GJ. Phytocannabinoids as novel therapeutic agents in CNS disorders. Pharmacol Ther 2011; 133:79-97. [PMID: 21924288 DOI: 10.1016/j.pharmthera.2011.09.002] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 08/20/2011] [Indexed: 10/17/2022]
Abstract
The Cannabis sativa herb contains over 100 phytocannabinoid (pCB) compounds and has been used for thousands of years for both recreational and medicinal purposes. In the past two decades, characterisation of the body's endogenous cannabinoid (CB) (endocannabinoid, eCB) system (ECS) has highlighted activation of central CB(1) receptors by the major pCB, Δ(9)-tetrahydrocannabinol (Δ(9)-THC) as the primary mediator of the psychoactive, hyperphagic and some of the potentially therapeutic properties of ingested cannabis. Whilst Δ(9)-THC is the most prevalent and widely studied pCB, it is also the predominant psychotropic component of cannabis, a property that likely limits its widespread therapeutic use as an isolated agent. In this regard, research focus has recently widened to include other pCBs including cannabidiol (CBD), cannabigerol (CBG), Δ(9)tetrahydrocannabivarin (Δ(9)-THCV) and cannabidivarin (CBDV), some of which show potential as therapeutic agents in preclinical models of CNS disease. Moreover, it is becoming evident that these non-Δ(9)-THC pCBs act at a wide range of pharmacological targets, not solely limited to CB receptors. Disorders that could be targeted include epilepsy, neurodegenerative diseases, affective disorders and the central modulation of feeding behaviour. Here, we review pCB effects in preclinical models of CNS disease and, where available, clinical trial data that support therapeutic effects. Such developments may soon yield the first non-Δ(9)-THC pCB-based medicines.
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Affiliation(s)
- Andrew J Hill
- School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6UB, United Kingdom
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86
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Serrano A, Parsons LH. Endocannabinoid influence in drug reinforcement, dependence and addiction-related behaviors. Pharmacol Ther 2011; 132:215-41. [PMID: 21798285 DOI: 10.1016/j.pharmthera.2011.06.005] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 06/17/2011] [Indexed: 12/12/2022]
Abstract
The endogenous cannabinoid system is an important regulatory system involved in physiological homeostasis. Endocannabinoid signaling is known to modulate neural development, immune function, metabolism, synaptic plasticity and emotional state. Accumulating evidence also implicates brain endocannabinoid signaling in the etiology of drug addiction which is characterized by compulsive drug seeking, loss of control in limiting drug intake, emergence of a negative emotional state in the absence of drug use and a persistent vulnerability toward relapse to drug use during protracted abstinence. In this review we discuss the effects of drug intake on brain endocannabinoid signaling, evidence implicating the endocannabinoid system in the motivation for drug consumption, and drug-induced alterations in endocannabinoid function that may contribute to various aspects of addiction including dysregulated synaptic plasticity, increased stress responsivity, negative affective states, drug craving and relapse to drug taking. Current knowledge of genetic variants in endocannabinoid signaling associated with addiction is also discussed.
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Affiliation(s)
- Antonia Serrano
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA
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87
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Brents LK, Reichard EE, Zimmerman SM, Moran JH, Fantegrossi WE, Prather PL. Phase I hydroxylated metabolites of the K2 synthetic cannabinoid JWH-018 retain in vitro and in vivo cannabinoid 1 receptor affinity and activity. PLoS One 2011; 6:e21917. [PMID: 21755008 PMCID: PMC3130777 DOI: 10.1371/journal.pone.0021917] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 06/08/2011] [Indexed: 01/17/2023] Open
Abstract
Background K2 products are synthetic cannabinoid-laced, marijuana-like drugs of abuse, use of which is often associated with clinical symptoms atypical of marijuana use, including hypertension, agitation, hallucinations, psychosis, seizures and panic attacks. JWH-018, a prevalent K2 synthetic cannabinoid, is structurally distinct from Δ9-THC, the main psychoactive ingredient in marijuana. Since even subtle structural differences can lead to differential metabolism, formation of novel, biologically active metabolites may be responsible for the distinct effects associated with K2 use. The present study proposes that K2's high adverse effect occurrence is due, at least in part, to distinct JWH-018 metabolite activity at the cannabinoid 1 receptor (CB1R). Methods/Principal Findings JWH-018, five potential monohydroxylated metabolites (M1–M5), and one carboxy metabolite (M6) were examined in mouse brain homogenates containing CB1Rs, first for CB1R affinity using a competition binding assay employing the cannabinoid receptor radioligand [3H]CP-55,940, and then for CB1R intrinsic efficacy using an [35S]GTPγS binding assay. JWH-018 and M1–M5 bound CB1Rs with high affinity, exhibiting Ki values that were lower than or equivalent to Δ9-THC. These molecules also stimulated G-proteins with equal or greater efficacy relative to Δ9-THC, a CB1R partial agonist. Most importantly, JWH-018, M2, M3, and M5 produced full CB1R agonist levels of activation. CB1R-mediated activation was demonstrated by blockade with O-2050, a CB1R-selective neutral antagonist. Similar to Δ9-THC, JWH-018 and M1 produced a marked depression of locomotor activity and core body temperature in mice that were both blocked by the CB1R-preferring antagonist/inverse agonist AM251. Conclusions/Significance Unlike metabolites of most drugs, the studied JWH-018 monohydroxylated compounds, but not the carboxy metabolite, retain in vitro and in vivo activity at CB1Rs. These observations, combined with higher CB1R affinity and activity relative to Δ9-THC, may contribute to the greater prevalence of adverse effects observed with JWH-018-containing products relative to cannabis.
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Affiliation(s)
- Lisa K. Brents
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Emily E. Reichard
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Sarah M. Zimmerman
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Jeffery H. Moran
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- Public Health Laboratory, Arkansas Department of Health, Little Rock, Arkansas, United States of America
| | - William E. Fantegrossi
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Paul L. Prather
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- * E-mail:
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88
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Pro-epileptic effects of the cannabinoid receptor antagonist SR141716 in a model of audiogenic epilepsy. Epilepsy Res 2011; 96:250-6. [PMID: 21733658 DOI: 10.1016/j.eplepsyres.2011.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 06/09/2011] [Accepted: 06/11/2011] [Indexed: 01/06/2023]
Abstract
Endocannabinoid system and its CB1 receptors are suggested to provide endogeneous protection against seizures. The present study examines whether CB1 receptors contribute to resistance to seizures and kindling epileptogenesis in a model of audiogenic epilepsy. Three groups of Wistar rats were used: rats unsusceptible to audiogenic seizures, rats with acquired resistance to audiogenic seizures and rats with reproducible audiogenic running seizures. Chronic treatment with the CB1 receptor antagonist SR141716 (5 daily dosing of 30mg/kg) did not change innate resistance to audiogenic seizures in non-epileptic rats but reverted acquired seizure resistance in rats which lost their epileptic sensitivity with repeated testing. In the latter rats, audiogenic running seizures reappeared for at least two weeks after the end of treatment. In rats with reproducible seizure response, acutely, SR lengthened audiogenic seizures due to prolongation or appearance, de novo, of post-running limbic clonus without any effect on running seizure per se. This limbic component mimicked audiogenic kindling and indicated propagation of sound-induced brainstem seizure to the limbic forebrain. After chronic SR administration the incidence of the limbic clonus remained to be increased for at least two weeks. The present study supports the hypothesis about a role of CB1 receptors in endogeneous anticonvulsive mechanisms of the brain.
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89
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Wendt H, Soerensen J, Wotjak CT, Potschka H. Targeting the endocannabinoid system in the amygdala kindling model of temporal lobe epilepsy in mice. Epilepsia 2011; 52:e62-5. [PMID: 21627644 DOI: 10.1111/j.1528-1167.2011.03079.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The endocannabinoid system can be considered as a putative target to affect ictogenesis as well as the generation of a hyperexcitable epileptic network. Therefore, we evaluated the effect of a CB1 receptor agonist (WIN55.212-2) and of an inhibitor of the enzymatic degradation of the endocannabinoid anandamide (fatty acid hydrolase inhibitor URB597) in the amygdala kindling model of temporal lobe epilepsy. Only minor effects on seizure thresholds and seizure parameters without a clear dose-dependency were observed in fully kindled mice. When evaluating the impact on kindling acquisition, WIN55.212-2 significantly delayed the progression of seizure severity. In contrast, URB597 did not affect the development of seizures in the kindling paradigm. Analysis of cell proliferation and neurogenesis during the kindling process revealed that URB597 significantly reduced the number of newborn neurons. These data give first evidence that CB1-receptor activation might render a disease-modifying approach. Future studies are necessary that further analyze the role of CB1 receptors and to confirm the efficacy of CB1-receptor agonists in other models of chronic epilepsy.
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Affiliation(s)
- Hannes Wendt
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Koeniginstrasse 16, Munich, Germany
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90
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Goffin K, Van Paesschen W, Van Laere K. In vivo activation of endocannabinoid system in temporal lobe epilepsy with hippocampal sclerosis. Brain 2011; 134:1033-40. [DOI: 10.1093/brain/awq385] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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91
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Luszczki JJ, Misiuta-Krzesinska M, Florek M, Tutka P, Czuczwar SJ. Synthetic cannabinoid WIN 55,212-2 mesylate enhances the protective action of four classical antiepileptic drugs against maximal electroshock-induced seizures in mice. Pharmacol Biochem Behav 2011; 98:261-7. [PMID: 21238473 DOI: 10.1016/j.pbb.2011.01.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 12/31/2010] [Accepted: 01/08/2011] [Indexed: 11/18/2022]
Abstract
The aim of this study was to determine the effect of WIN 55,212-2 mesylate (WIN--a non-selective cannabinoid CB1 and CB2 receptor agonist) on the protective action of four classical antiepileptic drugs (carbamazepine, phenytoin, phenobarbital, and valproate) in the mouse maximal electroshock seizure (MES) model. The results indicate that WIN (10 mg/kg, i.p.) significantly enhanced the anticonvulsant action of carbamazepine, phenytoin, phenobarbital and valproate in the MES test in mice. WIN (5 mg/kg) potentiated the anticonvulsant action of carbamazepine and valproate, but not that of phenytoin or phenobarbital in the MES test in mice. However, WIN administered alone and in combination with carbamazepine, phenytoin, phenobarbital and valproate significantly reduced muscular strength in mice in the grip-strength test. In the passive avoidance task, WIN in combination with phenobarbital, phenytoin and valproate significantly impaired long-term memory in mice. In the chimney test, only the combinations of WIN with phenobarbital and valproate significantly impaired motor coordination in mice. In conclusion, WIN enhanced the anticonvulsant action of carbamazepine, phenytoin, phenobarbital and valproate in the MES test. However, the utmost caution is advised when combining WIN with classical antiepileptic drugs due to impairment of motor coordination and long-term memory and/or reduction of skeletal muscular strength that might appear during combined treatment.
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Affiliation(s)
- Jarogniew J Luszczki
- Department of Pathophysiology, Medical University of Lublin, Jaczewskiego 8, PL 20-090 Lublin, Poland.
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92
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Guggenhuber S, Monory K, Lutz B, Klugmann M. AAV vector-mediated overexpression of CB1 cannabinoid receptor in pyramidal neurons of the hippocampus protects against seizure-induced excitoxicity. PLoS One 2010; 5:e15707. [PMID: 21203567 PMCID: PMC3006205 DOI: 10.1371/journal.pone.0015707] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 11/19/2010] [Indexed: 11/19/2022] Open
Abstract
The CB1 cannabinoid receptor is the most abundant G-protein coupled receptor in the brain and a key regulator of neuronal excitability. There is strong evidence that CB1 receptor on glutamatergic hippocampal neurons is beneficial to alleviate epileptiform seizures in mouse and man. Therefore, we hypothesized that experimentally increased CB1 gene dosage in principal neurons would have therapeutic effects in kainic acid (KA)-induced hippocampal pathogenesis. Here, we show that virus-mediated conditional overexpression of CB1 receptor in pyramidal and mossy cells of the hippocampus is neuroprotective and moderates convulsions in the acute KA seizure model in mice. We introduce a recombinant adeno-associated virus (AAV) genome with a short stop element flanked by loxP sites, for highly efficient attenuation of transgene expression on the transcriptional level. The presence of Cre-recombinase is strictly necessary for expression of reporter proteins or CB1 receptor in vitro and in vivo. Transgenic CB1 receptor immunoreactivity is targeted to glutamatergic neurons after stereotaxic delivery of AAV to the dorsal hippocampus of the driver mice NEX-cre. Increased CB1 receptor protein levels in hippocampal lysates of AAV-treated Cre-mice is paralleled by enhanced cannabinoid-induced G-protein activation. KA-induced seizure severity and mortality is reduced in CB1 receptor overexpressors compared with AAV-treated control animals. Neuronal damage in the hippocampal CA3 field is specifically absent from AAV-treated Cre-transgenics, but evident throughout cortical areas of both treatment groups. Our data provide further evidence for a role of increased CB1 signaling in pyramidal hippocampal neurons as a safeguard against the adverse effects of excessive excitatory network activity.
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Affiliation(s)
- Stephan Guggenhuber
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Krisztina Monory
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- * E-mail: (MK); (BL)
| | - Matthias Klugmann
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- * E-mail: (MK); (BL)
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93
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Zurolo E, Iyer A, Spliet W, Van Rijen P, Troost D, Gorter J, Aronica E. CB1 and CB2 cannabinoid receptor expression during development and in epileptogenic developmental pathologies. Neuroscience 2010; 170:28-41. [DOI: 10.1016/j.neuroscience.2010.07.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 06/30/2010] [Accepted: 07/02/2010] [Indexed: 01/15/2023]
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94
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Tree K, Caravagna C, Hilaire G, Peyronnet J, Cayetanot F. Anandamide centrally depresses the respiratory rhythm generator of neonatal mice. Neuroscience 2010; 170:1098-109. [PMID: 20800658 DOI: 10.1016/j.neuroscience.2010.08.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 08/02/2010] [Accepted: 08/19/2010] [Indexed: 11/26/2022]
Abstract
Endogenous cannabinoid receptors are widely distributed throughout the CNS, including the brainstem, and modulate a variety of functions, including breathing. In adult rats, activation of cannabinoid 1 receptors has been shown to depress breathing. Here in neonatal mice, we used in vitro electrophysiology, pharmacology, and immunohistochemistry to analyse the central effects of the endocannabinoid anandamide (AEA) on the activity of the medullary respiratory rhythm generator (RRG). First of all, in vitro electrophysiology on medullary preparations has revealed that bath application of AEA (30 μM, 15 min) significantly depressed respiratory activity. Secondly, applying pre-treatments with alpha-1 (Prazosin, 5 μM, 10 min) and alpha-2 (Yohimbine, 5 μM, 10 min) adrenoceptor antagonists prior to AEA application abolished the AEA-induced depression of the RRG. Finally, immunostaining revealed a dense network of fibres positive for the cannabinoid 1 receptor in the ventrolateral medulla (VLM), a region known to contain both the RRG and the modulatory A1/C1 catecholaminergic group. Moreover, cannabinoid 1 receptor positive fibres were found in close apposition with A1/C1 catecholaminergic cells, identified by the presence of tyrosine hydroxylase. In regard of our electrophysiological, pharmacological and immunostaining results, we conclude that AEA has a central depressive effect on the neonatal RRG, probably via the medullary A1/C1 catecholaminergic neurons which are already known to modulate the respiratory rhythm generator.
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Affiliation(s)
- K Tree
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille CRN2M, Département de Physiologie Neurovégétative (PNV), Université Paul Cézanne Aix Marseille III, Faculté des Sciences et Techniques St. Jérôme, UMR, 6231 CNRS, Marseille, France
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95
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Selective reduction of cholecystokinin-positive basket cell innervation in a model of temporal lobe epilepsy. J Neurosci 2010; 30:8993-9006. [PMID: 20592220 DOI: 10.1523/jneurosci.1183-10.2010] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Perisomatic inhibition from basket cells plays an important role in regulating pyramidal cell output. Two major subclasses of CA1 basket cells can be identified based on their expression of either cholecystokinin (CCK) or parvalbumin. This study examined their fates in the mouse pilocarpine model of temporal lobe epilepsy. Overall, immunohistochemical labeling of GABAergic boutons in the pyramidal cell layer of CA1 was preserved in the mouse model. However, CCK-labeled boutons in this layer were chronically reduced, whereas parvalbumin-containing boutons were conserved. Immunohistochemistry for cannabinoid receptor 1 (CB(1)), another marker for CCK-containing basket cells, also labeled fewer boutons in pilocarpine-treated mice. Hours after status epilepticus, electron microscopy revealed dark degenerating terminals in the pyramidal cell layer with lingering CCK and CB(1) immunoreactivity. In mice with recurrent seizures, carbachol-induced enhancement of spontaneous IPSCs (sIPSCs) originating from CCK-containing basket cells was accordingly reduced in CA1 pyramidal cells. By suppressing sIPSCs from CCK-expressing basket cells, a CB(1) agonist reverted the stimulatory effects of carbachol in naive mice to levels comparable with those observed in cells from epileptic mice. The agatoxin-sensitive component of CA1 pyramidal cell sIPSCs from parvalbumin-containing interneurons was increased in pilocarpine-treated mice, and miniature IPSCs were reduced, paralleling the decrease in CCK-labeled terminals. Altogether, the findings are consistent with selective reduction in perisomatic CA1 pyramidal cell innervation from CCK-expressing basket cells in mice with spontaneous seizures and a greater reliance on persisting parvalbumin innervation. This differential alteration in inhibition may contribute to the vulnerability of the network to seizure activity.
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96
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Zheng Y, Stiles L, Hamilton E, Smith PF, Darlington CL. The effects of the synthetic cannabinoid receptor agonists, WIN55,212-2 and CP55,940, on salicylate-induced tinnitus in rats. Hear Res 2010; 268:145-50. [PMID: 20630477 DOI: 10.1016/j.heares.2010.05.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 05/20/2010] [Accepted: 05/24/2010] [Indexed: 11/25/2022]
Abstract
Previous studies in animals and humans have shown that, in some cases at least, anti-epileptic drugs can reduce the severity of tinnitus. Given that cannabinoid receptor agonists have been shown to exert anti-epileptic effects in some circumstances, we investigated whether two synthetic CB(1)/CB(2) receptor agonists, WIN55,212-2, and CP55,940, could inhibit the behavioural manifestations of salicylate-induced tinnitus in rats in a conditioned suppression task. We found that neither WIN55,212-2 (3.0 mg/kg s.c) nor CP55,940 (0.1 or 0.3 mg/kg s.c), significantly reduced conditioned behaviour associated with tinnitus. However, both 3 mg/kg WIN55,212-2 and 0.3 mg/kg CP55,940 did significantly increase tinnitus-related behaviour compared to the vehicle control groups. These results suggest that cannabinoid receptor agonists may not be useful in the treatment of salicylate-induced tinnitus and that at certain doses, they could actually exacerbate the condition.
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Affiliation(s)
- Yiwen Zheng
- Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago Medical School, PO Box 913, Dunedin, New Zealand.
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97
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Hill AJ, Weston SE, Jones NA, Smith I, Bevan SA, Williamson EM, Stephens GJ, Williams CM, Whalley BJ. Δ⁹-Tetrahydrocannabivarin suppresses in vitro epileptiform and in vivo seizure activity in adult rats. Epilepsia 2010; 51:1522-32. [PMID: 20196794 DOI: 10.1111/j.1528-1167.2010.02523.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE We assessed the anticonvulsant potential of the phytocannabinoid Δ⁹-tetrahydrocannabivarin (Δ⁹-THCV) by investigating its effects in an in vitro piriform cortex (PC) brain slice model of epileptiform activity, on cannabinoid CB1 receptor radioligand-binding assays and in a generalized seizure model in rats. METHODS Δ⁹-THCV was applied before (10 μm Δ⁹-THCV) or during (10-50 μm Δ⁹-THCV) epileptiform activity induced by Mg²(+) -free extracellular media in adult rat PC slices and measured using multielectrode array (MEA) extracellular electrophysiologic techniques. The actions of Δ⁹-THCV on CB1 receptors were examined using [³H]SR141716A competition binding and [³⁵S]GTPγS assays in rat cortical membranes. Effects of Δ⁹-HCV (0.025-2.5 mg/kg) on pentylenetetrazole (PTZ)-induced seizures in adult rats were also assessed. RESULTS After induction of stable spontaneous epileptiform activity, acute Δ⁹ -THCV application (≥ 20 μm) significantly reduced burst complex incidence and the amplitude and frequency of paroxysmal depolarizing shifts (PDSs). Furthermore, slices pretreated with 10 μm Δ⁹-THCV prior to induction of epileptiform activity exhibited significantly reduced burst complex incidence and PDS peak amplitude. In radioligand-binding experiments, Δ⁹-THCV acted as a CB1 receptor ligand, displacing 0.5 nm [³H]SR141716A with a Ki∼290 nm, but exerted no agonist stimulation of [³⁵S]GTPγS binding. In PTZ-induced seizures in vivo, 0.25 mg/kg Δ⁹-THCV significantly reduced seizure incidence. DISCUSSION These data demonstrate that Δ⁹-THCV exerts antiepileptiform and anticonvulsant properties, actions that are consistent with a CB1 receptor-mediated mechanism and suggest possible therapeutic application in the treatment of pathophysiologic hyperexcitability states.
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Affiliation(s)
- Andrew J Hill
- School of Pharmacy, University of Reading, Whiteknights, Reading, Berkshire, UK
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98
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Jones NA, Hill AJ, Smith I, Bevan SA, Williams CM, Whalley BJ, Stephens GJ. Cannabidiol displays antiepileptiform and antiseizure properties in vitro and in vivo. J Pharmacol Exp Ther 2009; 332:569-77. [PMID: 19906779 DOI: 10.1124/jpet.109.159145] [Citation(s) in RCA: 230] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Plant-derived cannabinoids (phytocannabinoids) are compounds with emerging therapeutic potential. Early studies suggested that cannabidiol (CBD) has anticonvulsant properties in animal models and reduced seizure frequency in limited human trials. Here, we examine the antiepileptiform and antiseizure potential of CBD using in vitro electrophysiology and an in vivo animal seizure model, respectively. CBD (0.01-100 muM) effects were assessed in vitro using the Mg(2+)-free and 4-aminopyridine (4-AP) models of epileptiform activity in hippocampal brain slices via multielectrode array recordings. In the Mg(2+)-free model, CBD decreased epileptiform local field potential (LFP) burst amplitude [in CA1 and dentate gyrus (DG) regions] and burst duration (in all regions) and increased burst frequency (in all regions). In the 4-AP model, CBD decreased LFP burst amplitude (in CA1 only at 100 muM CBD), burst duration (in CA3 and DG), and burst frequency (in all regions). CBD (1, 10, and 100 mg/kg) effects were also examined in vivo using the pentylenetetrazole model of generalized seizures. CBD (100 mg/kg) exerted clear anticonvulsant effects with significant decreases in incidence of severe seizures and mortality compared with vehicle-treated animals. Finally, CBD acted with only low affinity at cannabinoid CB(1) receptors and displayed no agonist activity in [(35)S]guanosine 5'-O-(3-thio)triphosphate assays in cortical membranes. These findings suggest that CBD acts, potentially in a CB(1) receptor-independent manner, to inhibit epileptiform activity in vitro and seizure severity in vivo. Thus, we demonstrate the potential of CBD as a novel antiepileptic drug in the unmet clinical need associated with generalized seizures.
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Affiliation(s)
- Nicholas A Jones
- School of Pharmacy, University of Reading, Whiteknights, Reading RG6 6AJ, UK
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Armstrong C, Morgan RJ, Soltesz I. Pursuing paradoxical proconvulsant prophylaxis for epileptogenesis. Epilepsia 2009; 50:1657-69. [PMID: 19552655 DOI: 10.1111/j.1528-1167.2009.02173.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
There are essentially two potential treatment options for any acquired disorder: symptomatic or prophylactic. For acquired epilepsies that follow a variety of different brain insults, there remains a complete lack of prophylactic treatment options, whereas at the same time these epilepsies are notoriously resistant, once they have emerged, to symptomatic treatments with antiepileptic drugs. The development of prophylactic strategies is logistically challenging, both for basic researchers and clinicians. Nevertheless, cannabinoid-targeting drugs provide a very interesting example of a system within the central nervous system (CNS) that can have very different acute and long-term effects on hyperexcitability and seizures. In this review, we outline research on cannabinoids suggesting that although cannabinoid antagonists are acutely proconvulsant, they may have beneficial effects on long-term hyperexcitability following brain insults of multiple etiologies, making them promising candidates for further investigation as prophylactics against acquired epilepsy. We then discuss some of the implications of this finding on future attempts at prophylactic treatments, specifically, the very short window within which prevention may be possible, the possibility that traditional anticonvulsants may interfere with prophylactic strategies, and the importance of moving beyond anticonvulsants-even to proconvulsants-to find the ideal preventative strategy for acquired epilepsy.
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Affiliation(s)
- Caren Armstrong
- Department of Anatomy and Neurobiology, University of California, Irvine, California, USA.
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Romo-Parra H, Misgeld U, Yanovsky Y. Regular firing of a single output neuron reduces its own inhibition through endocannabinoids in substantia nigra pars reticulata of juvenile mice. Neuroscience 2009; 160:596-605. [PMID: 19272417 DOI: 10.1016/j.neuroscience.2009.02.062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 02/25/2009] [Accepted: 02/27/2009] [Indexed: 11/26/2022]
Abstract
Depolarization-induced suppression of inhibition in substantia nigra pars reticulata suggests that burst-like activity but not regular firing suffices to activate presynaptic endocannabinoid CB1 receptors. To more closely determine the type of activity required, we applied gramicidin perforated patch recording under visual control to substantia nigra slices of juvenile mice. We found that evoked inhibitory postsynaptic currents (eIPSCs) were reduced in amplitude by the spontaneous firing of a neuron under study, whereas silencing this neuron enhanced inhibitory responses. Autonomous firing reduced eIPSCs to 78%+/-2% in a time- but not frequency-dependent manner. The phenomenon which we termed firing-induced suppression of inhibition was cannabinoid receptor subtype 1-dependent, whereas adenosine A1 receptors played only a minor role. Depletion of intracellular Ca(2+) stores abolished the firing-induced suppression of inhibition suggesting that Ca(2+) release from internal stores is necessary for the production of endocannabinoids during autonomous firing. We suggest that the Ca(2+) influx during autonomous activity of pars reticulata neurons suffices to selectively dampen incoming inhibition from striatal neurons because it is amplified by ryanodine receptor-mediated Ca(2+) release from intracellular stores.
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Affiliation(s)
- H Romo-Parra
- Institut für Physiologie und Pathophysiologie, Universität Heidelberg, Heidelberg, Germany.
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