Since the airing of former Surgeon General Nominee Sanjay Gupta’s documentary “Weed” on CNN in July we’ve seen a large shift in public attitudes of how medical cannabis is perceived. How was this shift in attitude achieved? The documentary certainly hits a soft spot and follows the story of six year old Charlotte Figi and her battle with Dravet’s Syndrome, a severe form of childhood epilepsy that resulted in hundreds of seizures a week. Already being on tons of prescription medications that hardly alleviated her seizures, Charlotte’s parents were running out of options. They had heard of successes using cannabis, in particular the non-psychoactive component cannabidiol (CBD) but were reluctant to give cannabis to their five year old daughter. However with the increasing severity of her seizures they were willing to try anything. The Figi’s gave first gave their daughter cannabis when she was five and the results were miraculous, causing her to go from up to three hundred grand mal seizures a week to only two to three in a month. Since the release of the documentary, many parents with children diagnosed with similar childhood epilepsy disorders are advocating for this treatment, hoping for a similar outcome in their own kids.
Elucidating the mechanism of action of cannabidiols
Eighty percent of patients with Dravet’s syndrome have a mutation in the gene SCNA1 which provides the instructions for the production of a subunit of a sodium ion channel protein found in the brain. These channels allow for the generation of electrical impulses in the brain which are controlled by the opening and closing of ion channels. When opened these ion channels allow for the flow of positively charged sodium resulting in the propagation of an electrical signal. However when SCN1A is mutated it causes changes in the structure of the ion channel produced causing perturbations in its function. How cannabidiols modulate these perturbations in ion channel function is still unclear however it appears to inhibit seizure spread in the central nervous system through a non-cannabinoid type 1 receptor (CB1R) response.
Current and future research
Since the discovery of CBD’s effectiveness to treat seizures, other chemically related compounds in the cannabis plant are being researched for similar purposes. One such compound is another cannabinoid called cannabidivarin or CBDV which is nearly identical to CBD and has been patented for the treatment of epilepsy by GW Pharmaceuticals. A recent study conducted by The University of Reading researchers investigated CBDV’s anti-epileptic properties by inducing seizures in rats using a compound called pentylenetetrazole (PTZ). They found that the administration of CBDV suppressed changes in gene expression of epilepsy related genes induced by PTZ and also reduced seizure severity. These findings in animal models support the further development of CBDV as a treatment for epilepsy.