With the endocannabinoid system and its interaction with the CBD, ∆-9-THC and ∆-8-THC covered, let us have a look at a cannabinoid many in the cannabis industry have been searching for like King Arthur's knights sought the Holy Grail: the "primitive" phytocannabinoid tetrahydrocannabivarin (THCV).
Phytocannabinoid: delta-9-tetrahydrocannabivarin (∆-9-THCV)
THCV is present in trace to very low percentages in most modern cannabis. At one time in wild strains, it was present in more equitable levels with other cannabinoids. Cross breeding of cannabis, mostly to create high THC cultivars, resulted in low levels of THCV being produced. Currently, chemovars high in THCV are very rare. Interest in the medical properties of this cannabinoid are making the industry take notice and some cultivators are working to develop and a few have produced useful higher THCV chemovars and are producing concentrates. Expect to see much more about this phytocannabinoid in the future.
The acidic version of tetrahydrocannabivarin called THCV-A is the form produced by the cannabis plant. Like the other phytocannabinoids, decarboxylation yields the active form, ∆-9-THCV which interacts with the endocannabinoid system. It is a type of tetrahydrocannabinol which, of course, differs in chemical structure from the familiar ∆-9-THC. The difference may seem small, with THCV having a shorter side chain composed of three carbon atoms compared to the five carbon side chain of THC. As we have seen with the ∆-8-THC variety of tetrahydrocannabinol, a very small modification of structure caused by the movement of chemical bonds results in differences in how it interacts with the endocannabinoid receptors and the effects produced. The much bigger difference of two carbon atoms in the length of the side chains makes ∆-9-THCV behave quite differently than THC.
THCV has some characteristics of both the AEA and 2-AG endocannabinoids. The phytocannabinoid interacts with the CB1 receptor; but at the lower dose range found in modern cultivars (strains), it does not activate the receptor. It instead blocks THC from being able to access CB1 and can block some of THC's euphoric effects. In high dose ranges, ∆-9-THCV activates the CB1 receptor producing a more intense but shorter lasting euphoric effect than ∆-9-THC. THCV has been the only phytocannabinoid found to directly partially activate the CB2 receptor, suggesting a significant role in regulating inflammation. Interestingly, tetrahydrocannabivarin also shows activity at the 5-HT (serotonin) receptor which is the target for many antidepressants.
The medical benefits of tetrahydrocannabivarin have not been as well studied as THC and CBD because of the relative scarcity of the drug. There has been research showing THCV to be an appetite suppressant, have anxiolytic (anti-anxiety) effects, be anti-convulsive and have effects on metabolism which decrease blood sugar levels. The anti-inflammatory and neuroprotective properties of ∆-9-THCV suggest a role in the treatment of Parkinson's disease, multiple sclerosis and other neurodegenerative conditions.
Today, THCV is not very available to medical cannabis patients at concentrations which make exploring the possible benefits practical. In the future, THCV cultivars and concentrates will be further developed and refined. That said, understanding how it interacts with the endocannabinoid system can let one use the subtle effects of THCV to optimize medical cannabis treatment. Look to strains with THCV to decrease some of the euphoric (the high) effects of ∆-9-THC. Although dose ranges are unknown for controlling blood sugar levels, diabetic patients should consider THCV containing chemovars preferred to take advantage of any possible benefits. Patients with poor appetite or cachexia should avoid THCV strains due to the camabinoid's appetite suppressing effects. Neurodegenerative patients should also consider THCV chemovars as preferred when choosing between chemovars with appropriate cannabinoid and terpene profiles for their condition.
Back to the Big Picture and Chemovar Considerations
THCV is of course a very small piece of the cannabinoid puzzle, but one which will become larger as the industry develops chemovars and products with high concentrations of tetrahydrocannabivarin. As it becomes more widely available, the medical benefits and range of effective doses will be better defined. At the concentrations present in most cannabis today, it is useful for moderating the psychoactive effects of THC. With the potential to decrease appetite, THCV containing chemovars are best avoided in patients with cachexia or poor appetite as a symptom. The potential effects on stabilizing blood sugar levels make a chemovar with THCV a preferred choice for diabetics while those with neurodegenerative conditions should also consider its presence as a plus.
Brian Nichol MD