Tag Archives: treatment

Compound in cannabis may help treat epilepsy, researchers say

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“British researchers have determined that a little-studied chemical in the cannabis plant could lead to effective treatments for epilepsy, with few to no side effects.

The team at Britain’s University of Reading, working with GW Pharmaceuticals and Otsuka Pharmaceuticals, tested cannabidivarin, or CBDV, in rats and mice afflicted with six types of epilepsy and found it “strongly suppressed seizures” without causing the uncontrollable shaking and other side effects of existing anti-epilepsy drugs.

The casual use of marijuana — or cannabis — to control seizures dates back to ancient times. Its most prominent component, THC, is among those shown in animal studies to have strong anti-convulsant properties…”

http://articles.latimes.com/2012/sep/14/news/la-sn-cannabis-cbdv-epilepsy-20120914

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-demand activation of the endocannabinoid system in the control of neuronal excitability and epileptiform seizures.

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Abstract

“Neurons intensively exchange information among each other using both inhibitory and excitatory neurotransmitters. However, if the balance of excitation and inhibition is perturbed, the intensity of excitatory transmission may exceed a certain threshold and epileptic seizures can occur. As the occurrence of epilepsy in the human population is about 1%, the search for therapeutic targets to alleviate seizures is warranted. Extracts of Cannabis sativa have a long history in the treatment of various neurological diseases, including epilepsy. However, cannabinoids have been reported to exert both pro- and anti-convulsive activities. The recent progress in understanding the endogenous cannabinoid system has allowed new insights into these opposing effects of cannabinoids. When excessive neuronal activity occurs, endocannabinoids are generated on demand and activate cannabinoid type 1 (CB1) receptors. Using mice lacking CB1 receptors in principal forebrain neurons in a model of epileptiform seizures, it was shown that CB1 receptors expressed on excitatory glutamatergic neurons mediate the anti-convulsive activity of endocannabinoids. Systemic activation of CB1 receptors by exogenous cannabinoids, however, are anti- or pro-convulsive, depending on the seizure model used. The pro-convulsive activity of exogenous cannabinoids might be explained by the notion that CB1 receptors expressed on inhibitory GABAergic neurons are also activated, leading to a decreased release of GABA, and to a concomitant increase in seizure susceptibility. The concept that the endogenous cannabinoid system is activated on demand suggests that a promising strategy to alleviate seizure frequency is the enhancement of endocannabinoid levels by inhibiting the cellular uptake and the degradation of these endogenous compounds.”

http://www.ncbi.nlm.nih.gov/pubmed/15450934

The Endocannabinoid System Controls Key Epileptogenic Circuits in the Hippocampus

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“Balanced control of neuronal activity is central in maintaining function and viability of neuronal circuits. The endocannabinoid system tightly controls neuronal excitability. Here, we show that endocannabinoids directly target hippocampal glutamatergic neurons to provide protection against acute epileptiform seizures in mice. Functional CB1 cannabinoid receptors are present on glutamatergic terminals of the hippocampal formation, colocalizing with vesicular glutamate transporter 1 (VGluT1). Conditional deletion of the CB1 gene either in cortical glutamatergic neurons or in forebrain GABAergic neurons, as well as virally induced deletion of the CB1 gene in the hippocampus, demonstrate that the presence of CB1 receptors in glutamatergic hippocampal neurons is both necessary and sufficient to provide substantial endogenous protection against kainic acid (KA)-induced seizures. The direct endocannabinoid-mediated control of hippocampal glutamatergic neurotransmission may constitute a promising therapeutic target for the treatment of disorders associated with excessive excitatory neuronal activity.”

“In conclusion, our study reveals a mechanism through which the endocannabinoid system is able to provide on-demand protection against acute behavioral seizures. CB1 expression on hippocampal glutamatergic circuits accounts for this protection and might represent a suitable target for the treatment of neurological disorders associated with excessive neuronal excitation.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1769341/

The Endogenous Cannabinoid System Regulates Seizure Frequency and Duration in a Model of Temporal Lobe Epilepsy

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“Several lines of evidence suggest that cannabinoid compounds are anticonvulsant. However, the anticonvulsant potential of cannabinoids and, moreover, the role of the endogenous cannabinoid system in regulating seizure activity has not been tested in an in vivo model of epilepsy that is characterized by spontaneous, recurrent seizures. Here, using the rat pilocarpine model of epilepsy, we show that the marijuana extract Δ9-tetrahydrocannabinol (10 mg/kg) as well as the cannabimimetic, 4,5-dihydro-2-methyl-4(4-morpholinylmethyl)-1-(1-naphthalenyl-carbonyl)-6H-pyrrolo[3,2,1-i,j]quinolin-6-one [R(+)WIN55,212 (5 mg/kg)], completely abolished spontaneous epileptic seizures. Conversely, application of the cannabinoid CB1 receptor (CB1) antagonist, N-(piperidin-1-yl-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamidehydrochloride (SR141716A), significantly increased both seizure duration and frequency. In some animals, CB1 receptor antagonism resulted in seizure durations that were protracted to a level consistent with the clinical condition status epilepticus… These data indicate not only anticonvulsant activity of exogenously applied cannabinoids but also suggest that endogenous cannabinoid tone modulates seizure termination and duration through activation of the CB1 receptor… By demonstrating a role for the endogenous cannabinoid system in regulating seizure activity, these studies define a role for the endogenous cannabinoid system in modulating neuroexcitation and suggest that plasticity of the CB1 receptor occurs with epilepsy.”

“Characterized by spontaneously recurrent seizures, epilepsy is one of the most common neurological conditions. Understanding the factors that contribute to seizure initiation and termination has important implications for our ability to treat epilepsy and for the potential development of novel anticonvulsant agents. Previous evidence has suggested that the endogenous cannabinoid system may be a novel locus of anticonvulsant activity in the brain. Using the maximal electroshock model of short-term seizure, our laboratory determined that cannabinoid compounds block seizure spread via a cannabinoid CB1 receptor-dependent mechanism. Further study revealed that application of a CB1 receptor antagonist lowered the electroshock seizure threshold, indicating that elimination of endogenous cannabinoid tone at the CB1 receptor may increase seizure susceptibility.”

“The CB1 receptor is the most highly expressed G-protein-coupled receptor in brain and has been implicated in regulation of neuronal excitability. The endogenous cannabinoids, arachidonylethanolamine and 2-arachidonylglycerol (2-AG), are synthesized “on demand” in response to sustained neuronal depolarization and elevated intracellular calcium levels; both of these events occur with seizure activity. The neuronal hyperexcitability that accompanies seizure discharge may stimulate endogenous cannabinoid synthesis and subsequently result in CB1 receptor activation. In light of cannabinoid effects on neurotransmission, increased CB1 receptor activation could influence seizure activity. However, no studies have evaluated the role of the endogenous cannabinoid system in an intact model of epilepsy.”

“This study was initiated to evaluate the role of the CB1 receptor and the endogenous cannabinoid system in regulating seizure activity in a long-term model of epilepsy. We used the pilocarpine model of temporal lobe, partial-complex epilepsy; a rat model of acquired, refractory epilepsy that produces spontaneous recurrent seizures for the lifetime of the animal. The pilocarpine model has been shown to closely resemble human refractory partial-complex epilepsy. In this study, seizure frequency and duration were determined by continuous electrographic and video recording of each epileptic animal. The CB1 receptor agonists R(+)WIN55,212 and Δ9-tetrahydrocannabinol (THC) were evaluated for anticonvulsant efficacy. In addition to agonist effects on seizure activity, the effect of CB1 receptor antagonism on seizure frequency and duration was evaluated using the specific antagonist SR141716A. Hippocampal levels of 2-AG during short-term, pilocarpine-induced seizures were measured to determine whether a correlation exists between endogenous cannabinoid synthesis and seizure activity. In addition, Western blot and immunohistochemical analyses were used to evaluate hippocampal CB1 receptor protein expression in the brains of chronically epileptic and sham control rats. The findings presented suggest an anticonvulsant role for the endogenous cannabinoid system and demonstrate that long-term plasticity of the CB1 receptor occurs with epilepsy.”

“Therapeutic Implications for Cannabinoids in the Treatment of Epilepsy. Seizures in patients with refractory, partial-complex epilepsy can be difficult to control despite the use of currently available anticonvulsant medications and surgical interventions. Therefore, there is a clear need for the development of more effective anticonvulsant agents. Some epilepsy patients, seeking alternative treatments, have perceived improvement with marijuana. This has prompted several countries to consider the legalization of marijuana for epilepsy treatment. The pilocarpine model represents a refractory epileptic condition that is not readily treated by conventional anticonvulsants. Our results demonstrate that activation of the CB1 receptor by cannabinoid drugs and possibly endogenous ligands significantly alters seizure activity and is more effective than conventional anticonvulsants in treating the refractory seizures produced in the pilocarpine model. Although the dose dependence and long-term effects of cannabinoid administration on epilepsy must be further investigated, the results presented here provide evidence that warrants a comprehensive assessment of cannabinoid use in the control of refractory epilepsy via the use of animal models and placebo-controlled clinical trials. Although the psychoactive side effects of cannabinoids make their use in the treatment of epilepsy impractical, understanding the mechanisms of endogenous cannabinoid-mediated anticonvulsant action may lead to the development of novel compounds that do not manifest behavioral toxicity. Further investigation of the cannabinoid anticonvulsant phenomenon may illuminate novel therapeutic targets for the treatment of temporal lobe epilepsy as well as more clearly define the physiological function of the endogenous cannabinoid system in brain.”

http://jpet.aspetjournals.org/content/307/1/129.long

Marijuana, endocannabinoids, and epilepsy: Potential and challenges for improved therapeutic intervention.

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Abstract

  “Phytocannabinoids isolated from the cannabis plant have broad potential in medicine that has been well recognized for many centuries. It is presumed that these lipid soluble signaling molecules exert their effects in both the central and peripheral nervous system in large part through direct interaction with metabotropic cannabinoid receptors. These same receptors are also targeted by a variety of endogenous cannabinoids including 2-arachidonoyl glycerol and anandamide. Significant effort over the last decade has produced an enormous advance in our understanding of both the cellular and the synaptic physiology of endogenous lipid signaling systems. This increase in knowledge has left us better prepared to carefully evaluate the potential for both natural and synthetic cannabinoids in the treatment of a variety of neurological disorders. In the case of epilepsy, long standing interest in therapeutic approaches that target endogenous cannabinoid signaling systems are, for the most part, not well justified by available clinical data from human epileptics. Nevertheless, basic science experiments have clearly indicated a key role for endogenous cannabinoid signaling systems in moment to moment regulation of neuronal excitability. Further it has become clear that these systems can both alter and be altered by epileptiform activity in a wide range of in vitro and in vivo models of epilepsy. Collectively these observations suggest clear potential for effective therapeutic modulation of endogenous cannabinoid signaling systems in the treatment of human epilepsy, and in fact, further highlight key obstacles that would need to be addressed to reach that goal.”

http://www.ncbi.nlm.nih.gov/pubmed/22178327

Marijuana: an effective antiepileptic treatment in partial epilepsy? A case report and review of the literature.

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Abstract

“Although more data are needed, animal studies and clinical experience suggest that marijuana or its active constituents may have a place in the treatment of partial epilepsy. Here we present the case of a 45-year-old man with cerebral palsy and epilepsy who showed marked improvement with the use of marijuana. This case supports other anecdotal data suggesting that marijuana use may be a beneficial adjunctive treatment in some patients with epilepsy. Although challenging because of current federal regulations, further studies are needed to examine the role of marijuana in the treatment of this disorder.”

http://www.ncbi.nlm.nih.gov/pubmed/17609644

Suppression of fibroblast metalloproteinases by ajulemic acid, a nonpsychoactive cannabinoid acid.

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Abstract

   “Production of matrix metalloproteinases (MMP) in joint tissue of patients with inflammatory arthritis facilitates cartilage degradation and bone erosion, and leads to joint deformities and crippling. Thus, MMPs are important targets for agents designed to treat inflammatory arthritis. Oral administration of ajulemic acid (AjA), a synthetic, nonpsychoactive cannabinoid acid, prevents joint tissue injury in rats with adjuvant arthritis. AjA binds to and activates PPARgamma directly. Therefore, we investigated the influence of AjA on MMP production in human fibroblast-like synovial cells (FLS), and examined the role of PPARgamma in the mechanism of action of AjA. FLS, treated or not with a PPARgamma antagonist, were treated with AjA then stimulated with TNFalpha or IL-1alpha. Release of MMPs-1, 3, and 9 was measured by ELISA. The influence of AjA on MMP-3 release from stimulated PPARgamma positive (PPAR+/-) and PPARgamma null (PPAR-/-) mouse embryonic fibroblasts (MEF) was also examined. Addition of AjA to FLS suppressed production of MMPs whether or not PPARgamma activation was blocked. Secretion of MMP-3 was also suppressed by AjA in both TNFalpha- and IL-1alpha-stimulated PPARgamma+/- and PPARgamma-/- MEF. Suppression of MMP secretion from FLS by AjA appears to be PPARgamma independent. Prevention by AjA of joint tissue injury and crippling in the rat adjuvant arthritis model may be explained in large part by inhibition of MMPs. These results suggest that AjA may be useful for treatment of patients with rheumatoid arthritis and osteoarthritis.”

http://www.ncbi.nlm.nih.gov/pubmed/16927387

Ajulemic acid (IP-751): Synthesis, proof of principle, toxicity studies, and clinical trials

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Abstract

  “Ajulemic acid (CT-3, IP-751, 1′,1′-dimethylheptyl-Delta8-tetrahydrocannabinol-11-oic acid) (AJA) has a cannabinoid-derived structure; however, there is no evidence that it produces psychotropic actions when given at therapeutic doses. In a variety of animal assays, AJA shows efficacy in models for pain and inflammation. Furthermore, in the rat adjuvant arthritis model, it displayed a remarkable action in preventing the destruction of inflamed joints. A phase-2 human trial with chronic, neuropathic pain patients suggested that AJA could become a useful drug for treating this condition. Its low toxicity, particularly its lack of ulcerogenicity, further suggests that it will have a highly favorable therapeutic index and may replace some of the current anti-inflammatory/analgesic medications. Studies to date indicate a unique mechanism of action for AJA that may explain its lack of adverse side effects.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2751505/

Activation of peripheral cannabinoid CB1 and CB2 receptors suppresses the maintenance of inflammatory nociception: a comparative analysis

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“Effects of locally administered agonists and antagonists for cannabinoid CB1 and CB2 receptors on mechanical and thermal hypersensitivity were compared after the establishment of chronic inflammation.”

“Cannabinoids act locally through distinct CB1 and CB2 mechanisms to suppress mechanical hypersensitivity after the establishment of chronic inflammation, at doses that produced modest changes in thermal hyperalgesia. Additive antihyperalgesic effects were observed following prophylactic co-administration of the CB1– and CB2-selective agonists. Our results suggest that peripheral cannabinoid antihyperalgesic actions may be exploited for treatment of inflammatory pain states.”

“In summary, our results demonstrate that selective activation of CB1 or CB2 receptors in the inflamed paw is sufficient to suppress tactile allodynia and mechanical hyperalgesia. This suppression is observed under conditions in which only a partial suppression of thermal hyperalgesia was observed. Collectively, our data suggest that peripheral cannabinoid analgesic mechanisms may be exploited to suppress the tactile hypersensitivity observed in chronic inflammatory pain states.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2042894/