Endocannabinoid CB1 receptors are involved in antiepileptogenic effect of low frequency electrical stimulation during perforant path kindling in rats.

“Administration of low-frequency electrical stimulation (LFS) at the kindling site has an antiepileptogenic effect. In the present study, we investigated the role of cannabinoid receptors type 1 (CB1) in mediating the inhibitory effects of LFS on the development of perforant path kindled seizures.

RESULTS:

Application of LFS had inhibitory effect on development of kindled seizures (kindling rate). Microinjection of AM281 (0.5 μg/μl) immediately after the last kindling stimulation (before LFS application) reduced the inhibitory effect of LFS on the kindling rate and suppressed the effects of LFS on potentiation (increasing the magnitude) of both population spike amplitude and population excitatory postsynaptic potential slope during kindling acquisition. AM281 pretreatment also prevented the effects of LFS on kindling-induced increase in early and late paired pulse depression. The higher dose of AM281 (2 μg/μl) failed to exert the effects observed with its lower dose (0.5 μg/μl). In addition, there was a decreased CB1 receptors immunostaining in kindled animals compared to control. However, application of LFS following kindling stimulations led to overexpression of CB1 receptors in the dentate gyrus.

CONCLUSION:

Obtained results showed that activation of overexpressed cannabinoid CB1 receptors by endogenous cannabinoids may have a role in mediating the inhibitory effect of LFS on perforant path kindled seizures.” https://www.ncbi.nlm.nih.gov/pubmed/29800824 https://www.sciencedirect.com/science/article/pii/S0920121117304291?via%3Dihub]]>

Review of the neurological benefits of phytocannabinoids.

“Numerous physical, psychological, and emotional benefits have been attributed to marijuana since its first reported use in 2,600 BC in a Chinese pharmacopoeia. The phytocannabinoids, cannabidiol (CBD), and delta-9-tetrahydrocannabinol (Δ9-THC) are the most studied extracts from cannabis sativa subspecies hemp and marijuana. CBD and Δ9-THC interact uniquely with the endocannabinoid system (ECS). Through direct and indirect actions, intrinsic endocannabinoids and plant-based phytocannabinoids modulate and influence a variety of physiological systems influenced by the ECS.

METHODS:

In 1980, Cunha et al. reported anticonvulsant benefits in 7/8 subjects with medically uncontrolled epilepsy using marijuana extracts in a phase I clinical trial. Since then neurological applications have been the major focus of renewed research using medical marijuana and phytocannabinoid extracts.

RESULTS:

Recent neurological uses include adjunctive treatment for malignant brain tumors, Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, neuropathic pain, and the childhood seizure disorders Lennox-Gastaut and Dravet syndromes. In addition, psychiatric and mood disorders, such as schizophrenia, anxiety, depression, addiction, postconcussion syndrome, and posttraumatic stress disorders are being studied using phytocannabinoids.

CONCLUSIONS:

In this review we will provide animal and human research data on the current clinical neurological uses for CBD individually and in combination with Δ9-THC. We will emphasize the neuroprotective, antiinflammatory, and immunomodulatory benefits of phytocannabinoids and their applications in various clinical syndromes.” https://www.ncbi.nlm.nih.gov/pubmed/29770251 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5938896/]]>

Control of excessive neural circuit excitability and prevention of epileptic seizures by endocannabinoid signaling

“Progress in research on endocannabinoid signaling has greatly advanced our understanding of how it controls neural circuit excitability in health and disease. In general, endocannabinoid signaling at excitatory synapses suppresses seizures by inhibiting glutamate release. In contrast, endocannabinoid signaling promotes seizures by inhibiting GABA release at inhibitory synapses. The physiological distribution of endocannabinoid signaling molecules becomes disrupted with the development of epileptic focus in patients with mesial temporal lobe epilepsy and in animal models of experimentally induced epilepsy. Augmentation of endocannabinoid signaling can promote the development of epileptic focus at initial stages. However, at later stages, increased endocannabinoid signaling delays it and suppresses spontaneous seizures. Thus, the regulation of endocannabinoid signaling at specific synapses that cause hyperexcitability during particular stages of disease development may be effective for treating epilepsy and epileptogenesis.” https://link.springer.com/article/10.1007/s00018-018-2834-8 http://www.x-mol.com/paper/661834]]>

Efficacy of CBD-enriched medical cannabis for treatment of refractory epilepsy in children and adolescents – An observational, longitudinal study.

Cover image volume 40, Issue 5 “The objective of this observational study was to evaluate the efficacy of medical cannabis for the treatment of refractory epilepsy. Fifty-seven patients (age 1-20 years) with epilepsy of various etiologies were treated with Cannabis oil extract (CBD/THC ratio of 20:1) for at least 3 months (Median follow up time-18 months). Forty-Six Patients were included in the efficacy analysis. Average CBD dose was11.4 mg/kg/d. Twenty-six patients (56%) had ≤50% reduction in mean monthly seizure frequency. There was no statistically significant difference in response rate among various epilepsy etiologies, and cannabis strain used. Younger age at treatment onset (<10 years) and higher CBD dose (>11 mg/kg/d) were associated with better response to treatment. Adverse reactions were reported in 46% of patients and were the main reason for treatment cessation. Our results suggest that adding CBD-enriched cannabis extract to the treatment regimen of patients with refractory epilepsy may result in a significant reduction in seizure frequency according to parental reports.”
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