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

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

“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

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Could Cannabidiol be a Treatment Option for Intractable Childhood and Adolescent Epilepsy?

 “Epilepsy is an important disease that affects brain function, particularly in those under 3 years old. Uncontrolled seizures can affect cognitive function and quality of life. For these reasons, many trials have been conducted to investigate treatments for pediatric epilepsy. Currently, many antiepileptic drugs are available for the treatment of epilepsy, but cases of intractable epilepsy continue to exist.

In the past, cannabis has been tested as a potential treatment of intractable epilepsy.

Since 2013, 10 epilepsy centers in America have conducted research regarding the efficacy of cannabis to treat epilepsy. Cannabis has many components, including cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). THC has psychoactive properties exerted through its binding of the cannabinoid receptor (CBR) whereas CBD is a CBR antagonist. The inhibition of epilepsy by CBD may therefore be caused by various mechanisms, although the detailed mechanisms of CBD actions have not yet been well defined. In most studies, trial doses of CBD were 2-5 mg/kg/day.

Several such studies have shown that CBD does have efficacy for treatment of epilepsy.

Reported adverse effects of CBD were mostly mild, including drowsiness, diarrhea, and decreased appetite. Severe adverse reactions requiring treatment, such as status epilepticus, have also been reported but it is not clear that this is related to CBD. Furthermore, many previous studies have been limited by an open-label or survey design. In future, double-blind, controlled trials are required and the use of CBD to treat other neurological problems should also be investigated.”  https://www.ncbi.nlm.nih.gov/pubmed/28775950

“Most studies suggest anticonvulsant effects of CBD, and consider most adverse effects to be mild. It must be borne in mind that CBD is still illegal in many contexts. However, it has the potential to treat various neurological problems, including epilepsy.” http://www.j-epilepsy.org/journal/view.php?doi=10.14581/jer.17003

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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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Assessing the role of serotonergic receptors in cannabidiol’s anticonvulsant efficacy.

“Cannabidiol (CBD) is a phytocannabinoid that has demonstrated anticonvulsant efficacy in several animal models of seizure. The current experiment validated CBD’s anticonvulsant effect using the acute pentylenetetrazol (PTZ) model.

While this work further confirms the anticonvulsant efficacy of CBD and supports its application in the treatment of human seizure disorders, additional research on CBD’s mechanism of action must be conducted.”

https://www.ncbi.nlm.nih.gov/pubmed/28624721

http://www.epilepsybehavior.com/article/S1525-5050(17)30122-1/fulltext

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Cannabidiol Treatment for Refractory Seizures in Sturge-Weber Syndrome.

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“Sturge-Weber syndrome results in leptomeningeal vascular malformations, medically refractory epilepsy, stroke(s), and cognitive impairments. Cannabidiol, a cannabinoid without psychoactive properties, has been demonstrated in preclinical models to possibly have anticonvulsant, antioxidant, and neuroprotective actions.

CONCLUSION:

This study suggests that cannabidiol may be well tolerated as adjunctive medication for seizure management and provides initial data supporting further study of cannabidiol in individuals with Sturge-Weber syndrome.”

https://www.ncbi.nlm.nih.gov/pubmed/28454984

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Protective Effects of Cannabidiol against Seizures and Neuronal Death in a Rat Model of Mesial Temporal Lobe Epilepsy.

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“The present study reports the behavioral, electrophysiological, and neuropathological effects of cannabidiol (CBD), a major non-psychotropic constituent of Cannabis sativa, in the intrahippocampal pilocarpine-induced status epilepticus (SE) rat model. Our findings demonstrate anticonvulsant and neuroprotective effects of CBD preventive treatment in the intrahippocampal pilocarpine epilepsy model, either as single or multiple administrations, reinforcing the potential role of CBD in the treatment of epileptic disorders.” https://www.ncbi.nlm.nih.gov/pubmed/28367124

“This study showed that CBD treatment reduces the behavioral severity and oscillatory electrographic changes of SE, the post-ictal lethargy, and the neuronal loss associated with the pilocarpine-induced SE rat model. More studies are needed to understand the specific mechanisms of action related to the neuroprotective and anticonvulsant effects of CBD in epilepsy.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5355474/

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The Direct Actions of Cannabidiol and 2-Arachidonoyl Glycerol at GABAA Receptors.

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“Cannabidiol (CBD) is a major non-intoxicating component of cannabis and possesses anti-epileptic, anxiolytic and anti-hyperalgesic properties.

Despite evidence that some endogenous and synthetic cannabinoids interact with GABAA receptors, no-one has yet investigated the effects of CBD.

Here we used two-electrode voltage clamp electrophysiology to compare the actions of CBD with those of the major central endocannabinoid, 2-arachidonoyl glycerol (2-AG) on human recombinant GABAA receptors (synaptic α1-6βg2 and extrasynaptic α4β2δ) expressed on Xenopus oocytes.

Taken together these results reveal a mode of action of CBD on specifically configured GABAA receptors that may be relevant to the anticonvulsant and anxiolytic effects of the compound.”

https://www.ncbi.nlm.nih.gov/pubmed/28249817

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Cannabidiol Prevents Cerebral Infarction Via a Serotonergic 5-Hydroxytryptamine1A Receptor–Dependent Mechanism

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“Cannabis contains ≈80 different cannabinoids, including the psychoactive component Δ9-tetrahydrocannabinol, and nonpsychoactive components, which include cannabidiol, cannabinol, and cannabigerol.

In those components, cannabidiol, a nonpsychoactive constituent of cannabis, was found to be an anticonvulsant in animal models of epilepsy and in humans with epilepsy. Moreover, cannabidiol has been shown to have antispasmodic, anxiolytic, antinausea, and antirheumatoid arthritic properties. In addition, cannabidiol has been shown to be protective against global and focal ischemic injury.

Cannabidiol has been reported to be a neuroprotectant, but the neuroprotective mechanism of cannabidiol remains unclear. We studied the neuroprotective mechanism of cannabidiol in 4-hour middle cerebral artery (MCA) occlusion mice.

Cannabidiol significantly reduced the infarct volume induced by MCA occlusion in a bell-shaped curve. Similarly, abnormal cannabidiol but not anandamide or methanandamide reduced the infarct volume.

Cannabidiol and abnormal cannabidiol reduced the infarct volume.

These results suggested that the neuroprotective effect of cannabidiol may be related to the increase in CBF through the serotonergic 5-HT1A receptor.”

http://stroke.ahajournals.org/content/36/5/1071

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

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