Δ 9 -Tetrahydrocannabinol promotes functional remyelination in the mouse brain

Myelin is the protective coating that surrounds nerve fibers and helps electrical signals move efficiently through the brain and spinal cord. Damage to myelin is a major feature of neurological disorders involving demyelination, making the repair of this protective layer an important therapeutic target.

In this mouse study, Δ9-THC promoted the regeneration of oligodendrocytes, the cells responsible for producing myelin, and enhanced remyelination in damaged white matter. THC treatment was also associated with improved recovery of motor function.

The researchers found that these effects involved activation of the CB1 cannabinoid receptor and the maturation of oligodendrocyte precursor cells into myelin-producing cells. The findings suggest that THC may have potential as a compound capable of supporting functional repair after myelin damage.

“Background and purpose: Research on demyelinating disorders aims to find novel molecules that are able to induce oligodendrocyte precursor cell differentiation to promote central nervous system remyelination and functional recovery. Δ9 -Tetrahydrocannabinol (THC), the most prominent active constituent of the hemp plant Cannabis sativa, confers neuroprotection in animal models of demyelination. However, the possible effect of THC on myelin repair has never been studied.

Experimental approach: By using oligodendroglia-specific reporter mouse lines in combination with two models of toxin-induced demyelination, we analysed the effect of THC on the processes of oligodendrocyte regeneration and functional remyelination.

Key results: We show that THC administration enhanced oligodendrocyte regeneration, white matter remyelination and motor function recovery. THC also promoted axonal remyelination in organotypic cerebellar cultures. THC remyelinating action relied on the induction of oligodendrocyte precursor differentiation upon cell cycle exit and via CB1 cannabinoid receptor activation.

Conclusions and implications: Overall, our study identifies THC administration as a promising pharmacological strategy aimed to promote functional CNS remyelination in demyelinating disorders.”

https://pubmed.ncbi.nlm.nih.gov/34216154/

“THC administration following cuprizone-induced demyelination enhanced oligodendrocyte regeneration, white matter remyelination and motor function recovery.”

“THC administration is a promising pharmacological strategy to promote functional CNS remyelination in demyelinating disorders.”

“Our study provides a novel therapeutic advantage of THC-based interventions in multiple sclerosis by promoting remyelination and functional recovery. New clinical trials with improved designs on cannabinoids in people with multiple sclerosis are needed now, considering these compounds as potential remyelinating/disease-modifying drugs to try to overcome previous failures. Our work also suggests that at least part of the neuroprotective action of phytocannabinoids in multiple sclerosis animal models and potentially in patients as well may be due to an enhanced CNS remyelination. Finally, this study also identifies THC as a potent inductor of oligodendrocyte progenitor cell differentiation under demyelination in mice, opening the possibility for this molecule to become a candidate drug to promote oligodendrocyte regeneration and remyelination in the treatment of demyelinating disorders.”

https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/bph.15608

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Anticonvulsant effect of cannabinoid receptor agonists in models of seizures in developing rats.

“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]]>

Guanfacine Attenuates Adverse Effects of Dronabinol (THC) on Working Memory in Adolescent-Onset Heavy Cannabis Users: A Pilot Study.

Image result for journal of neuropsychiatry and clinical neurosciences “The cannabinoid-1 receptor (CB1R) agonist Δ9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, adversely effects working memory performance in humans. The α2A-adrenoceptor (AR) agonist guanfacine improves working memory performance in humans. The authors aimed to determine the effects of short-term (6 days) treatment with guanfacine on adverse cognitive effects produced by THC. Employing a double-blind, placebo-controlled crossover design, the cognitive, subjective, and cardiovascular effects produced by oral THC (20 mg) administration were determined twice in the same cannabis users: once after treatment with placebo and once after treatment with guanfacine (3 mg/day). Although THC increased visual analog scores of subjective effects and heart rate, these increases were similar during treatment with placebo and guanfacine. THC did not significantly affect performance of a recognition memory task or blood pressure while individuals were maintained on either treatment. Although preliminary, these results suggest that guanfacine warrants further testing as a potential treatment for cannabis-induced cognitive deficits.” https://www.ncbi.nlm.nih.gov/pubmed/28641496   http://neuro.psychiatryonline.org/doi/10.1176/appi.neuropsych.16120328 “Guanfacine (brand name Estulic, Tenex and the extended release Intuniv; not to be confused with guaifenesin, an expectorant) is a sympatholytic drug used in the treatment of attention deficit hyperactivity disorder (ADHD), anxiety, and hypertension. It is a selective α2A receptor agonist“ https://en.wikipedia.org/wiki/Guanfacine Related image
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