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.

Current Issue

“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.

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
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