Category Archives: Epilepsy

An electrophysiological analysis of the anticonvulsant action of cannabidiol on limbic seizures in conscious rats.

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Abstract

“The effects of cannabidiol (CBD) on electrically evoked kindled seizures were studied in conscious, unrestrained rats with chronically implanted cortical and limbic electrodes, and the results were compared with those of delta 9-tetrahydrocannabinol (delta 9-THC), phenytoin (PHT), and ethosuximide (ESM). All drugs were anticonvulsant, but there were marked differences in their effects on afterdischarge (AD) threshold, duration, and amplitude. CBD, like PHT and delta 9-THC, elevated the AD threshold; in contrast, ESM decreased the threshold but suppressed AD spread. CBD, however, also resembled ESM inasmuch as both drugs decreased AD duration and amplitude. Electrophysiologically, the antiseizure effects of CBD were a combination of those of PHT and ESM. The combination of effects may account for the observation that CBD was the most efficacious of the drugs tested against limbic ADs and convulsions. Other properties of CBD were also noted: For example, compared with delta 9-THC, it is a much more selective anticonvulsant vis-à-vis motor toxicity. CBD also lacks the CNS excitatory effects produced by delta 9-THC, PHT, and ESM. These characteristics, combined with its apparently unique set of electrophysiological properties, support the suggestion that CBD has therapeutic potential as an antiepileptic.”

http://www.ncbi.nlm.nih.gov/pubmed/477630

Cannabidiol–antiepileptic drug comparisons and interactions in experimentally induced seizures in rats.

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Abstract

“A comparison of the anticonvulsant and neurotoxic effects of cannabidiol (CBD), delta 9tetrahydrocannabinol, cannabinol and antiepileptic drugs (phenytoin, phenobarbital, carbamazepine, chlordiazepoxide, clonazepam, ethosuximide and trimethadione) was made in rats. Median effective potencies (ED 50 values) for maximal electroshock, audiogenic seizures and TD50 values for a rotor rod neurotoxicity test were calculated. Additionally, the interactive effects of CBD and the antiepileptic drugs against maximal electroshock and audiogenic seizures were studied. Each drug was given orally at peak effect time. CBD was an effective and relatively potent anticonvulsant in both maximal electroshock and audiogenic seizure tests. The anticonvulsant potency of phenytoin was significantly increased when combined with phenobarbital, CBD and phenobarbital plus CBD. Additionally, CBD reliably reduced the anticonvulsant potencies of chlordiazepoxide, clonazepam, trimethadione and ethosuximide. These data indicate that CBD is an effective anticonvulsant with a specificity more comparable to drugs clinically effective in major than minor seizures. Furthermore, it appears that CBD enhances the anticonvulsant effects of the former and reduces the effects of the latter types of antiepileptic drugs.”

http://www.ncbi.nlm.nih.gov/pubmed/850145

Epileptiform seizures in domestic fowl. V. The anticonvulsant activity of delta9-tetrahydrocannabinol.

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Abstract

“The anticonvulsant activity of delta9-tetrahydrocannabinol (delta9-THC) has been determined against seizures induced in epileptic chickens by intermittent photic stimulation (IPS) and in epileptic and nonepileptic chickens by Metrazol. Intravenous administration of the drug reduced both the severity and incidence of seizures evoked by IPS in epileptic chickens. This anticonvulsant action was accompanied by a reduction in frequency of inter-ictal slow-wave high-voltage electroencephalographic activity and by the absence of spiking during IPS. delta9-THC did not affect the incidence of Metrazol-induced seizures in epileptic or nonepileptic chickens.”

http://www.ncbi.nlm.nih.gov/pubmed/1222370

Anticonvulsant activity of delta9-tetrahydrocannabinol compared with three other drugs.

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Abstract

“Delta9-tetrahydrocannabinol (THC) was compared with diphenylhydantoin (DPH), phenobarbital (PB) and chlordiazepoxide (CDP) using several standard laboratory procedures to determine anticonvulsant activity in mice, i.e., the maximal electroshock test (MES), and seizures induced by pentylenetetrazol, strychnine and nicotine. In the MES test, THC was the least potent and DPH the most potent blocker of hind limb tonic extensor convulsions whereas THC was the most potent and DPH the least potent in increasing the latency to this response and in preventing mortality. Seizures and mortality induced by pentylenetetrazol or by strychnine were enhanced by THC and DPH and were blocked by PB and CDP. In the test with nicotine, none of the four anticonvulsant agents prevented seizures; DPH was the only one which failed to increase latency; THC and DPH were less potent than PB and CDP in preventing mortality. THC most closely resembled DPH in the tests with chemical convulsant agents, but a sedative action of THC, resembling that of PB and CDP, was indicated by low ED5 0 for increased latency and for prevention of mortality in the MES test.”

http://www.ncbi.nlm.nih.gov/pubmed/1253828

Marijuana use and epilepsy: prevalance in patients of a tertiary care epilepsy center.

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Abstract

“The authors sought to determine the prevalence of marijuana use in patients with epilepsy by performing a telephone survey in a tertiary care epilepsy center. Twenty-one percent of subjects had used marijuana in the past year with the majority of active users reporting beneficial effects on seizures. Twenty-four percent of all subjects believed marijuana was an effective therapy for epilepsy. Despite limited evidence of efficacy, many patients with epilepsy believe marijuana is an effective therapy for epilepsy and are actively using it.”

http://www.ncbi.nlm.nih.gov/pubmed/15184622

Cannabidiol exerts anti-convulsant effects in animal models of temporal lobe and partial seizures.

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    “Cannabis sativa has been associated with contradictory effects upon seizure states despite its medicinal use by numerous people with epilepsy. We have recently shown that the phytocannabinoid cannabidiol (CBD) reduces seizure severity and lethality in the well-established in vivo model of pentylenetetrazole-induced generalised seizures, suggesting that earlier, small-scale clinical trials examining CBD effects in people with epilepsy warrant renewed attention… These results extend the anti-convulsant profile of CBD; when combined with a reported absence of psychoactive effects, this evidence strongly supports CBD as a therapeutic candidate for a diverse range of human epilepsies.”

http://www.ncbi.nlm.nih.gov/pubmed/22520455

Cannabidiol Displays Antiepileptiform and Antiseizure Properties In Vitro and In Vivo

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“CBD is the major nonpsychoactive component of Cannabis sativa whose structure was first described by Mechoulam and Shvo (1963); CBD has recently attracted renewed interest for its therapeutic potential in a number of disease states. CBD has been proposed to possess anticonvulsive, neuroprotective, and anti-inflammatory properties in humans.”

 “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…. These findings suggest that CBD acts, potentially in a CB1 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.”

“In conclusion, our data in separate in vitro models of epileptiform activity and, in particular, the beneficial reductions in seizure severity caused by CBD in an in vivo animal model of generalized seizures suggests that earlier, small-scale clinical trials for CBD in untreated epilepsy warrant urgent renewed investigation.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2819831/

Cannabidivarin is anticonvulsant in mouse and rat.

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“Phytocannabinoids in Cannabis sativa have diverse pharmacological targets extending beyond cannabinoid receptors and several exert notable anticonvulsant effects. For the first time, we investigated the anticonvulsant profile of the phytocannabinoid cannabidivarin (CBDV) in vitro and in in vivo seizure models.”

 

“CONCLUSIONS AND IMPLICATIONS:

These results indicate that CDBV is an effective anticonvulsant across a broad range of seizure models, does not significantly affect normal motor function and therefore merits further investigation in chronic epilepsy models to justify human trials.”

http://www.ncbi.nlm.nih.gov/pubmed/22970845

Δ⁹-Tetrahydrocannabivarin suppresses in vitro epileptiform and in vivo seizure activity in adult rats.

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“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.”

“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.”

http://www.ncbi.nlm.nih.gov/pubmed/20196794

On the application of cannabis in paediatrics and epileptology.

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Abstract

“An initial report on the therapeutic application of delta 9-THC (THC) (Dronabinol, Marinol) in 8 children resp. adolescents suffering from the following conditions, is given: neurodegenerative disease, mitochondriopathy, posthypoxic state, epilepsy, posttraumatic reaction. THC effected reduced spasticity, improved dystonia, increased initiative (with low dose), increased interest in the surroundings, and anticonvulsive action. The doses ranged from 0.04 to 0.12 mg/kg body weight a day. The medication was given as an oily solution orally in 7 patients, via percutaneous gastroenterostomy tube in one patient. At higher doses disinhibition and increased restlessness were observed. In several cases treatment was discontinued and in none of them discontinuing resulted in any problems. The possibility that THC-induced effects on ion channels and transmitters may explain its therapeutic activity seen in epileptic patients is discussed.”

http://www.ncbi.nlm.nih.gov/pubmed/15159680