Category Archives: Epilepsy

The Role of BK Channels in Antiseizure Action of the CB1 Receptor Agonist ACEA in Maximal Electroshock and Pentylenetetrazole Models of Seizure in Mice.

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“The anticonvulsant effect of cannabinoid compound has been shown in various models of seizure. On the other hand, there are controversial findings about the role of large conductance calcium-activated potassium (BK) channels in the pathogenesis of epilepsy. Also, there is no data regarding the effect of co-administration of cannabinoid type 1 (CB1) receptor agonists and BK channels antagonists in the acute models of seizure in mice.

In this study, the effect of arachidonyl-2′-chloroethylamide (ACEA), a CB1 receptor agonist, and a BK channel antagonist, paxilline, either alone or in combination was investigated.

Both pentylenetetrazole (PTZ) and maximal electroshock (MES) acute models of seizure were used to evaluate the protective effects of drugs. Mice were randomly selected in different groups: (i) control group; (ii) groups that received different doses of either paxilline or ACEA; and (iii) groups that received combinations of ACEA and paxillin at different doses. In MES model, prevention of hindlimb tonic extension (HLTE) was considered as protective effect. In PTZ model, the required dose of PTZ (mg/kg) to induce tonic-clonic seizure with loss of righting reflex was considered as seizure threshold. In PTZ model, while administration of ACEA per se (5 and 10 mg/kg) caused protective effect against seizure; however, co-administration of ACEA and ineffective doses of paxilline attenuated the antiseizure effects of paxilline. In MES model, while pretreatment by ACEA showed protective effects against seizure; however, co-administration of paxilline and ACEA caused an antagonistic interaction for their antiseizure properties.

Our results showed a protective effect of ACEA in both PTZ and MES acute models of seizure. This effect was attenuated by co-administration with paxilline, suggesting the involvement of BK channels in antiseizure activity of ACEA.”

https://www.ncbi.nlm.nih.gov/pubmed/28979317

Cannabidiol attenuates seizures and social deficits in a mouse model of Dravet syndrome.

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“Worldwide medicinal use of cannabis is rapidly escalating, despite limited evidence of its efficacy from preclinical and clinical studies. Here we show that cannabidiol (CBD) effectively reduced seizures and autistic-like social deficits in a well-validated mouse genetic model of Dravet syndrome (DS), a severe childhood epilepsy disorder caused by loss-of-function mutations in the brain voltage-gated sodium channel NaV1.1.

The duration and severity of thermally induced seizures and the frequency of spontaneous seizures were substantially decreased. Treatment with lower doses of CBD also improved autistic-like social interaction deficits in DS mice.

Phenotypic rescue was associated with restoration of the excitability of inhibitory interneurons in the hippocampal dentate gyrus, an important area for seizure propagation. Reduced excitability of dentate granule neurons in response to strong depolarizing stimuli was also observed.

The beneficial effects of CBD on inhibitory neurotransmission were mimicked and occluded by an antagonist of GPR55, suggesting that therapeutic effects of CBD are mediated through this lipid-activated G protein-coupled receptor.

Our results provide critical preclinical evidence supporting treatment of epilepsy and autistic-like behaviors linked to DS with CBD. We also introduce antagonism of GPR55 as a potential therapeutic approach by illustrating its beneficial effects in DS mice.

Our study provides essential preclinical evidence needed to build a sound scientific basis for increased medicinal use of CBD.”

https://www.ncbi.nlm.nih.gov/pubmed/28973916

http://www.pnas.org/content/early/2017/09/26/1711351114

Cannabidiol reduced frequency of convulsive seizures in drug resistant Dravet syndrome.

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BMJ Journals

“Study design

Design: Multinational double-blinded placebo-controlled trial. Patients randomised in 1:1 ratio to receive cannabidiol or placebo, in addition to stable antiepileptic treatment regime.

Study question

Setting: Twenty-three centres in Europe and USA.

 Patients: Patients aged 2 years to 18 years with established diagnosis of Dravet syndrome having at least four convulsive seizures during the 28-day baseline period despite regular antiepileptic medication.

Intervention: Adjunctive cannabidiol or placebo oral solution at 20 mg per kilogram of body weight per day.

Primary outcome: Percentage change in median frequency of convulsive seizures per month.

Follow-up period: Outcome measured over a 14-week treatment period in comparison to a 4-week baseline period.

Patient follow-up: One hundred and eight (90%) completed the trial: 85% (52/61) in the cannabidiol group and …”

http://ep.bmj.com/content/early/2017/09/22/archdischild-2017-313700

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

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“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

[Cannabis use in Epilepsy. Current situation in Argentina and abroad].

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“Although at present we have over 20 different types of drugs for epilepsy, 30 to 40% of patients continue to have seizures.

Preliminary data from human studies suggest that cannabis, cannabidiol in particular, is effective in the treatment of some patients with epilepsy.

However, the available data are limited and do not allow defnitive conclusions. Only randomized clinical trials with controlled double-blind, placebo-controlled utilizing secure preparations and one or more cannabinoids, will provide comprehensive information on the effcacy and safety of use.

In order to perform these trials it is necessary to have legislation authorizing the use of cannabis on epilepsy.”

 https://www.ncbi.nlm.nih.gov/pubmed/28898306

Parent use of cannabis for intractable pediatric epilepsy: Everyday empiricism and the boundaries of scientific medicine.

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Social Science & Medicine

“Cannabis is an increasingly sought-after remedy for US children with intractable (biomedically uncontrollable) epilepsy. However, like other complementary-alternative medicine (CAM) modalities, and particularly as a federally illegal, stigmatized substance, it is unsanctioned by mainstream medicine. Parents are largely on their own when it comes to learning about, procuring, dispensing, and monitoring treatments. Exploring how they manage is crucial to better assist them. Moreover, it can illuminate how ‘research’ done on the ground by laypeople variously disrupts and reinforces lay-expert and science-non-science divides. To those ends, in 2016, 25 Southern California parents who used, had used, or sought to use cannabis pediatrically for epilepsy/seizures were interviewed regarding their evidentiary standards, research methods, and aims when trying the drug. Parents generally described their work as experimentation; they saw their efforts as adhering to authorized scientific practices and standards, and as contributing to the authorized medical cannabis knowledge base. Findings subverted assumptions, based on an outdated stereotype of CAM, that cannabis-using parents do not believe in biomedicine. Indeed, parents’ desire for their children’s biomedical demarginalization, combined with biomedical dependency and a high caregiver burden, fueled a collaborative stance. Implications for understanding the boundaries of science are explored, as are norms for parent agency as ill children’s care managers, radicalization among people affected by contested illnesses, and the future of ‘medical marijuana.'”

https://www.ncbi.nlm.nih.gov/pubmed/28865255

http://www.sciencedirect.com/science/article/pii/S0277953617304756?via%3Dihub

 

An Update on Safety and Side Effects of Cannabidiol: A Review of Clinical Data and Relevant Animal Studies.

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Mary Ann Liebert, Inc. publishers

“This literature survey aims to extend the comprehensive survey performed by Bergamaschi et al. in 2011 on cannabidiol (CBD) safety and side effects. Apart from updating the literature, this article focuses on clinical studies and CBD potential interactions with other drugs.

Results: In general, the often described favorable safety profile of CBD in humans was confirmed and extended by the reviewed research. The majority of studies were performed for treatment of epilepsy and psychotic disorders. Here, the most commonly reported side effects were tiredness, diarrhea, and changes of appetite/weight. In comparison with other drugs, used for the treatment of these medical conditions, CBD has a better side effect profile. This could improve patients’ compliance and adherence to treatment. CBD is often used as adjunct therapy. Therefore, more clinical research is warranted on CBD action on hepatic enzymes, drug transporters, and interactions with other drugs and to see if this mainly leads to positive or negative effects, for example, reducing the needed clobazam doses in epilepsy and therefore clobazam’s side effects.

Conclusion: This review also illustrates that some important toxicological parameters are yet to be studied, for example, if CBD has an effect on hormones. Additionally, more clinical trials with a greater number of participants and longer chronic CBD administration are still lacking.”

 https://www.ncbi.nlm.nih.gov/pubmed/28861514
http://online.liebertpub.com/doi/10.1089/can.2016.0034

Even High Doses of Oral Cannabidol Do Not Cause THC-Like Effects in Humans

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Mary Ann Liebert, Inc. publishers

“Cannabidiol (CBD) is a cannabinoid of the cannabis plant devoid of intoxicating effects. It may be of therapeutic value in a large number of diseases, including epilepsy, anxiety disorders, depression, schizophrenic psychosis, inflammatory diseases, dystonia, nausea, and vomiting without causing relevant or severe side effects.

No biosynthetic enzyme or pathway exists in the human body to convert CBD to THC.

This short communication examines the question whether the experimental data presented in a study by Merrick et al. are of clinical relevance. These authors found that cannabidiol (CBD), a major cannabinoid of the cannabis plant devoid of psychotropic effects and of great interest for therapeutic use in several medical conditions, may be converted in gastric fluid into the psychoactive cannabinoids delta-8-THC and delta-9-THC to a relevant degree. They concluded that “the acidic environment during normal gastrointestinal transit can expose orally CBD-treated patients to levels of THC and other psychoactive cannabinoids that may exceed the threshold for a positive physiological response.” They issued a warning concerning oral use of CBD and recommend the development of other delivery methods.

However, the available clinical data do not support this conclusion and recommendation, since even high doses of oral CBD do not cause psychological, psychomotor, cognitive, or physical effects that are characteristic for THC or cannabis rich in THC. On the contrary, in the past decades and by several groups, high doses of oral CBD were consistently shown to cause opposite effects to those of THC in clinical studies. In addition, administration of CBD did not result in detectable THC blood concentrations.

Thus, there is no reason to avoid oral use of CBD, which has been demonstrated to be a safe means of administration of CBD, even at very high doses.”

https://www.ncbi.nlm.nih.gov/pubmed/28861499

http://online.liebertpub.com/doi/full/10.1089/can.2016.0036

“A Conversion of Oral Cannabidiol to Delta9-Tetrahydrocannabinol Seems Not to Occur in Humans.”  https://www.ncbi.nlm.nih.gov/pubmed/28861507

The potential role of cannabinoids in epilepsy treatment.

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“Epilepsy is one of the world’s oldest recognized and prevalent neurological diseases. It has a great negative impact on patients’ quality of life (QOL) as a consequence of treatment resistant seizures in about 30% of patients together with drugs’ side effects and comorbidities. Therefore, new drugs are needed and cannabinoids, above all cannabidiol, have recently gathered attention.

This review summarizes the scientific data from human and animal studies on the major cannabinoids which have been of interest in the treatment of epilepsy, including drugs acting on the endocannabinoid system.

Despite the fact that cannabis has been used for many purposes over 4 millennia, the development of drugs based on cannabinoids has been very slow. Only recently, research has focused on their potential effects and CBD is the first treatment of this group with clinical evidence of efficacy in children with Dravet syndrome; moreover, other studies are currently ongoing to confirm its effectiveness in patients with epilepsy.

On the other hand, it will be of interest to understand whether drugs acting on the endocannabinoid system will be able to reach the market and prove their known preclinical efficacy also in patients with epilepsy.”

https://www.ncbi.nlm.nih.gov/pubmed/28845714   http://www.tandfonline.com/doi/abs/10.1080/14737175.2017.1373019

 

“The role of cannabinoids and endocannabinoid system in the treatment of epilepsy. Cannabis has been used for thousands of years in the treatment of various diseases. Cannabinoids have been shown in preliminary animal model studies and in studies of patients with epilepsy to have antiepileptic activity. ” https://www.degruyter.com/view/j/joepi.ahead-of-print/joepi-2015-0034/joepi-2015-0034.xml
 
“Phytocannabinoids produce anticonvulsant effects through the endocannabinoid system, with few adverse effects.”

Anticonvulsant effect of cannabidiol in the pentylenetetrazole model: Pharmacological mechanisms, electroencephalographic profile, and brain cytokine levels.

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“Cannabidiol (CBD), the main nonpsychotomimetic compound from Cannabis sativa, inhibits experimental seizures in animal models and alleviates certain types of intractable epilepsies in patients.

Here we tested the hypothesis that CBD anticonvulsant mechanisms are prevented by cannabinoid (CB1 and CB2) and vanilloid (TRPV1) receptor blockers. We also investigated its effects on electroencephalographic (EEG) activity and hippocampal cytokines in the pentylenetetrazole (PTZ) model.

Pretreatment with CBD (60mg/kg) attenuated seizures induced by intraperitoneal, subcutaneous, and intravenous PTZ administration in mice. The effects were reversed by CB1, CB2, and TRPV1 selective antagonists (AM251, AM630, and SB366791, respectively). Additionally, CBD delayed seizure sensitization resulting from repeated PTZ administration (kindling). This cannabinoid also prevented PTZ-induced EEG activity and interleukin-6 increase in prefrontal cortex.

In conclusion, the robust anticonvulsant effects of CBD may result from multiple pharmacological mechanisms, including facilitation of endocannabinoid signaling and TRPV1 mechanisms. These findings advance our understanding on CBD inhibition of seizures, EEG activity, and cytokine actions, with potential implications for the development of new treatments for certain epileptic syndromes.”

https://www.ncbi.nlm.nih.gov/pubmed/28821005

http://www.epilepsybehavior.com/article/S1525-5050(17)30322-0/fulltext