The FAAH inhibitor URB597 suppresses hippocampal maximal dentate afterdischarges and restores seizure-induced impairment of short and long-term synaptic plasticity.

“Synthetic cannabinoids and phytocannabinoids have been shown to suppress seizures both in humans and experimental models of epilepsy.

However, they generally have a detrimental effect on memory and memory-related processes. Here we compared the effect of the inhibition of the endocannabinoid (eCB) degradation versus synthetic CB agonist on limbic seizures induced by maximal dentate activation (MDA) acute kindling. Moreover, we investigated the dentate gyrus (DG) granule cell reactivity and synaptic plasticity in naïve and in MDA-kindled anaesthetised rats.

We found that both the fatty acid amide hydrolase (FAAH) inhibitor URB597 and the synthetic cannabinoid agonist WIN55,212-2 displayed AM251-sensitive anti-seizure effects. WIN55,212-2, dose-dependently (0.5-2 mg/kg, i.p.) impaired short-term plasticity (STP) and long-term potentiation (LTP) at perforant path-DG synapses in naïve rats. Strikingly, URB597 (1 mg/kg, i.p.) was devoid of any deleterious effects in normal conditions, while it prevented seizure-induced alterations of both STP and LTP.

Our evidence indicates that boosting the eCB tone rather than general CB1 activation might represent a potential strategy for the development of a new class of drugs for treatment of both seizures and comorbid memory impairments associated with epilepsy.”

https://www.ncbi.nlm.nih.gov/pubmed/28894217

https://www.nature.com/articles/s41598-017-11606-1

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Anticonvulsant effect of cannabinoid receptor agonists in models of seizures in developing rats.

Epilepsia

“Although drugs targeting the cannabinoid system (e.g., CB1 receptor agonists) display anticonvulsant efficacy in adult animal models of seizures/epilepsy, they remain unexplored in developing animal models. However, cannabinoid system functions emerge early in development, providing a rationale for targeting this system in neonates.

We examined the therapeutic potential of drugs targeting the cannabinoid system in three seizure models in developing rats.

The mixed CB1/2 agonist and the CB1-specific agonist, but no other drugs, displayed anticonvulsant effects against clonic seizures in the DMCM model. By contrast, both CB1 and CB2 antagonism increased seizure severity. Similarly, we found that the CB1/2 agonist displayed antiseizure efficacy against acute hypoxia-induced seizures (automatisms, clonic and tonic-clonic seizures) and tonic-clonic seizures evoked by PTZ.

Early life seizures represent a significant cause of morbidity, with 30-40% of infants and children with epilepsy failing to achieve seizure remission with current pharmacotherapy. Identification of new therapies for neonatal/infantile epilepsy syndromes is thus of high priority.

These data indicate that the anticonvulsant action of the CB system is specific to CB1 receptor activation during early development and provide justification for further examination of CB1 receptor agonists as novel antiepileptic drugs targeting epilepsy in infants and children.” https://www.ncbi.nlm.nih.gov/pubmed/28691158

http://onlinelibrary.wiley.com/doi/10.1111/epi.13842/abstract

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Trial of Cannabidiol for Drug-Resistant Seizures in the Dravet Syndrome

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“BACKGROUND

The Dravet syndrome is a complex childhood epilepsy disorder that is associated with drug-resistant seizures and a high mortality rate. We studied cannabidiol for the treatment of drug-resistant seizures in the Dravet syndrome.

METHODS

In this double-blind, placebo-controlled trial, we randomly assigned 120 children and young adults with the Dravet syndrome and drug-resistant seizures to receive either cannabidiol oral solution at a dose of 20 mg per kilogram of body weight per day or placebo, in addition to standard antiepileptic treatment. The primary end point was the change in convulsive-seizure frequency over a 14-week treatment period, as compared with a 4-week baseline period.

RESULTS

The median frequency of convulsive seizures per month decreased from 12.4 to 5.9 with cannabidiol, as compared with a decrease from 14.9 to 14.1 with placebo (adjusted median difference between the cannabidiol group and the placebo group in change in seizure frequency, −22.8 percentage points; 95% confidence interval [CI], −41.1 to −5.4; P=0.01). The percentage of patients who had at least a 50% reduction in convulsive-seizure frequency was 43% with cannabidiol and 27% with placebo (odds ratio, 2.00; 95% CI, 0.93 to 4.30; P=0.08). The patient’s overall condition improved by at least one category on the seven-category Caregiver Global Impression of Change scale in 62% of the cannabidiol group as compared with 34% of the placebo group (P=0.02). The frequency of total seizures of all types was significantly reduced with cannabidiol (P=0.03), but there was no significant reduction in nonconvulsive seizures. The percentage of patients who became seizure-free was 5% with cannabidiol and 0% with placebo (P=0.08). Adverse events that occurred more frequently in the cannabidiol group than in the placebo group included diarrhea, vomiting, fatigue, pyrexia, somnolence, and abnormal results on liver-function tests. There were more withdrawals from the trial in the cannabidiol group.

CONCLUSIONS

Among patients with the Dravet syndrome, cannabidiol resulted in a greater reduction in convulsive-seizure frequency than placebo and was associated with higher rates of adverse events. (Funded by GW Pharmaceuticals; ClinicalTrials.gov number, NCT02091375.)”

http://www.nejm.org/doi/10.1056/NEJMoa1611618

“Cannabinoids for Epilepsy — Real Data, at Last”  http://www.nejm.org/doi/full/10.1056/NEJMe1702205

“Cannabidiol (CBD) Significantly Reduces Convulsive Seizure Frequency in Dravet Syndrome (DS): Results of a Multi-center, Randomized, Double-blind, Placebo-controlled Trial (GWPCARE1)” http://files.shareholder.com/downloads/AMDA-1TW341/201889199x0x919787/73B57FA6-CD45-4ABB-8C89-87EFEA36B4ED/1332B_AES_Poster_Dravet_Part_B_.pdf

“EPILEPSY AND MARIJUANA: CANNABIS DRUG REDUCES DRAVET SYNDROME SEIZURES IN LARGE-SCALE CLINICAL TRIAL” http://www.newsweek.com/cannabis-marijuana-dravet-syndrome-epilepsy-clinical-trial-614982

“Study proves medicinal cannabis can help children with severe epilepsy, researchers say” http://www.abc.net.au/news/2017-05-25/scientific-study-medicinal-cannabis-helps-children-with-epilepsy/8556180
 
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Cannabidiol in Medical Marijuana: Research Vistas and Potential Opportunities.

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“The high and increasing prevalence of medical marijuana consumption in the general population invites the need for quality evidence regarding its safety and efficacy. Herein, we synthesize extant literature pertaining to the phytocannabinoid cannabidiol (CBD) and its brain effects.

The principle phytocannabinoid Δ9-tetrahydrocannabinol (Δ9-THC) and CBD are the major pharmacologically active cannabinoids. The effect of CBD on brain systems as well as on phenomenological measures (e.g. cognitive function) are distinct and in many cases opposite to that of Δ9-THC.

Cannabidiol is without euphoriant properties, and exerts antipsychotic, anxiolytic, anti-seizure, as well as anti-inflammatory properties.

It is essential to parcellate phytocannabinoids into their constituent moieties as the most abundant cannabinoid have differential effects on physiologic systems in psychopathology measures. Disparate findings and reports related to effects of cannabis consumption reflect differential relative concentration of Δ9-THC and CBD.

Existing literature, notwithstanding its deficiencies, provides empirical support for the hypothesis that CBD may exert beneficial effects on brain effector systems/substrates subserving domain-based phenomenology. Interventional studies with purified CBD are warranted with a call to target-engagement proof-of-principle studies using the research domain criteria (RDoC) framework.” https://www.ncbi.nlm.nih.gov/pubmed/28501518

http://www.sciencedirect.com/science/article/pii/S1043661817303559

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Evaluation of Cannabidiol in Animal Seizure Models by the Epilepsy Therapy Screening Program (ETSP).

Neurochemical Research

“Cannabidiol (CBD) is a cannabinoid component of marijuana that has no significant activity at cannabinoid receptors or psychoactive effects. There is considerable interest in CBD as a therapy for epilepsy.

Almost a third of epilepsy patients are not adequately controlled by clinically available anti-seizure drugs (ASDs). Initial studies appear to demonstrate that CBD preparations may be a useful treatment for pharmacoresistant epilepsy.

The National Institute of Neurological Disorders and Stroke (NINDS) funded Epilepsy Therapy Screening Program (ETSP) investigated CBD in a battery of seizure models using a refocused screening protocol aimed at identifying pharmacotherapies to address the unmet need in pharmacoresistant epilepsy. Applying this new screening workflow, CBD was investigated in mouse 6 Hz 44 mA, maximal electroshock (MES), corneal kindling models and rat MES and lamotrigine-resistant amygdala kindling models.

Following intraperitoneal (i.p.) pretreatment, CBD produced dose-dependent protection in the acute seizure models; mouse 6 Hz 44 mA (ED50 164 mg/kg), mouse MES (ED50 83.5 mg/kg) and rat MES (ED50 88.9 mg/kg). In chronic models, CBD produced dose-dependent protection in the corneal kindled mouse (ED50 119 mg/kg) but CBD (up to 300 mg/kg) was not protective in the lamotrigine-resistant amygdala kindled rat. Motor impairment assessed in conjunction with the acute seizure models showed that CBD exerted seizure protection at non-impairing doses.

The ETSP investigation demonstrates that CBD exhibits anti-seizure properties in acute seizure models and the corneal kindled mouse. However, further preclinical and clinical studies are needed to determine the potential for CBD to address the unmet needs in pharmacoresistant epilepsy.”  https://www.ncbi.nlm.nih.gov/pubmed/28478594

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Cannabinoids and epilepsy — Introduction.

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“Over the past five years, the lay press and families of children with catastrophic epilepsies popularized the use of cannabis and cannabinoids to treat seizures. Many state legislatures have responded to the pressure from lay groups and have legalized medical cannabis, which is now available to a majority of people in the United States. Patients throughout the world are also obtaining and using cannabinoids to treat their epilepsy. There is an enormous dissociation between the widespread use of cannabis-based therapies to treat diverse epilepsies and our understanding about the efficacy and safety of different cannabinoids in treating different epilepsy syndromes.”  http://www.epilepsybehavior.com/article/S1525-5050(17)30042-2/abstract

http://www.thctotalhealthcare.com/category/epilepsy-2/

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Brain cannabinoid systems as targets for the therapy of neurological disorders.

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“Unprecedented developments in cannabinoid research within the past decade include discovery of a brain (CB1) and peripheral (CB2) receptor; endogenous ligands, anandamide, and 2-arachidonylglycerol; cannabinoid drug-induced partial and inverse agonism at CB1 receptors, antagonism of NMDA receptors and glutamate, and antioxidant activity; and preferential CB1 receptor localization in areas subserving spasticity, pain, abnormal involuntary movements, seizures, and amnesia. These endogenous structures and chemicals and mechanisms are potentially new pathophysiologic substrates, and targets for novel cannabinoid treatments, of several neurological disorders.” https://www.ncbi.nlm.nih.gov/pubmed/9974182 

“Endocannabinoid System in Neurological Disorders.” https://www.ncbi.nlm.nih.gov/pubmed/27364363
“Cannabinoids in the Treatment of Neurological Disorders” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4604187/
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Cannabinoids in treatment-resistant epilepsy: A review.

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“Treatment-resistant epilepsy (TRE) affects 30% of epilepsy patients and is associated with severe morbidity and increased mortality.

Cannabis-based therapies have been used to treat epilepsy for millennia, but only in the last few years have we begun to collect data from adequately powered placebo-controlled, randomized trials (RCTs) with cannabidiol (CBD), a cannabis derivative.

Previously, information was limited to case reports, small series, and surveys reporting on the use of CBD and diverse medical marijuana (MMJ) preparations containing: tetrahydrocannabinol (THC), CBD, and many other cannabinoids in differing combinations.

These RCTs have studied the safety and explored the potential efficacy of CBD use in children with Dravet Syndrome (DS) and Lennox-Gastaut Syndrome (LGS).

The role of the placebo response is of paramount importance in studying medical cannabis products given the intense social and traditional media attention, as well as the strong beliefs held by many parents and patients that a natural product is safer and more effective than FDA-approved pharmaceutical agents.

We lack valid data on the safety, efficacy, and dosing of artisanal preparations available from dispensaries in the 25 states and District of Columbia with MMJ programs and online sources of CBD and other cannabinoids. On the other hand, open-label studies with 100mg/ml CBD (Epidiolex®, GW Pharmaceuticals) have provided additional evidence of its efficacy along with an adequate safety profile (including certain drug interactions) in children and young adults with a spectrum of TREs.

Further, Phase 3 RCTs with Epidiolex support efficacy and adequate safety profiles for children with DS and LGS at doses of 10- and 20-mg/kg/day. This article is part of a Special Issue titled “Cannabinoids and Epilepsy”.”

https://www.ncbi.nlm.nih.gov/pubmed/28188044

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Treatment of Dravet Syndrome.

“Dravet syndrome is among the most challenging electroclinical syndromes. There is a high likelihood of recurrent status epilepticus; seizures are medically refractory; and patients have multiple co-morbidities, including intellectual disability, behaviour and sleep problems, and crouch gait. Additionally, they are at significant risk of sudden unexplained death.

This review will focus predominantly on the prophylactic medical management of seizures, addressing both first-line therapies (valproate and clobazam) as well as second-line (stiripentol, topiramate, ketogenic diet) or later options (levetiracetam, bromides, vagus nerve stimulation). Sodium channel agents-including carbamazepine, oxcarbazepine, phenytoin and lamotrigine-should be avoided, as they typically exacerbate seizures.

Several agents in development may show promise, specifically fenfluramine and cannabidiol, but they need further evaluation in randomized, controlled trials.

In addition to prophylactic treatment, all patients need home-rescue medication and a status epilepticus protocol that can be carried out in their local hospital. Families must be counselled on non-pharmacologic strategies to reduce seizure risk, including avoidance of triggers that commonly induce seizures (including hyperthermia, flashing lights and patterns).

In addition to addressing seizures, holistic care for a patient with Dravet syndrome must involve a multidisciplinary team that includes specialists in physical, occupational and speech therapy, neuropsychology, social work and physical medicine.”

http://www.ncbi.nlm.nih.gov/pubmed/27264138

http://www.thctotalhealthcare.com/category/dravet-syndome/

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Colocalization of cannabinoid receptor 1 with somatostatin and neuronal nitric oxide synthase in rat brain hippocampus.

“Somatostatin (SST), a growth hormone inhibitory peptide, is expressed in different parts of the brain and functions as a neurotransmitter and neuromodulator. In the central nervous system (CNS), SST inhibits Ca2+ influx and regulates neuronal excitability in the hippocampus, the brain region which plays a major role in seizure, as well as cognitive and memory function.

Much like SST, cannabinoid receptor 1 (CB1 receptor) is also widely distributed in the CNS, associated with memory function ad exerts inhibitory effects on seizure.

It is unknown whether overlapping functional activities of SST and CB1 receptor are also associated with coexpression in the hippocampus.

In the present study, we determined the colocalization between SST and CB1 receptor in adult rat brain hippocampus. In the CNS, the majority of SST positive interneurons coexpress neuronal nitric oxide synthase (nNOS). Accordingly, colocalization studies were also performed to determine whether nNOS positive neurons display comparable colocalization with CB1 receptor.

The findings suggested that SST and nNOS are expressed in most interneurons whereas CB1 receptor is present in both interneurons and projection neurons in hippocampal regions. The distinct neuronal populations either expressing CB1 receptor, SST and nNOS alone or colocalization were observed in a region specific manner.

Taken together, the observations described here anticipate the possibility of crosstalk between somatostatin subtypes and CB1 receptor in regulation of physiological activities in the hippocampus.”

http://www.ncbi.nlm.nih.gov/pubmed/26115586

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