Researchers found a molecule produced by the brain fights the harmful effects of marijuana in animals.
The molecule, called pregnenolone, prevents THC (the active ingredient in marijuana) from activating the CB1 brain receptor; overstimulation of this receptor is what causes a marijuana "high," an INSERM (Institut national de la santé et de la recherche médicale)news release reported.
The researchers believe this discovery could aid in the treatment of marijuana addiction; which they reported affects 20 million people globally.
About 30 percent of people between the ages of 16 and 24 are reported to be addicted to marijuana. If abused, marijuana can lead to "cognitive deficits and a general loss of motivation," the news release reported.
When THC binds to the CB1 cannabinoid receptors it decreases their ability to "[regulate] food intake, metabolism, cognitive processes and pleasure," the news release reported.
If the CB1 receptors are overstimulated this can eventually lead to substance dependance.
In the past pregnenolone (which is a steroid hormone) has been considered " inactive precursor used to synthesize all the other steroid hormones," this new research disputes that idea. Pregnenolone may actually fight the negative side effects associated with marijuana.
When high doses (higher than those consumed by a regular user) of THC activate the CB1 receptor they also trigger the release pregnenolone. The molecule binds to the same receptors and reduces some of the effects of the substance.
Pregnenolone works to reduce the amount of dopamine (which can lead to dependance) that is released as a result of THC.
The "negative feedback" from pregnenolone revealed an endogenous mechanism that protects the brain from overstimulation of the targeted receptors.
"The role of pregnenolone was discovered when, rats were given equivalent doses of cocaine, morphine, nicotine, alcohol and cannabis and the levels of several brain steroids (pregnenolone, testosterone, allopregnenolone, DHEA etc..) were measured. It was then found that only one drug, THC, increased brain steroids and more specifically selectively one steroid, pregnenolone, that went up 3000 [percent] for a period of two hours," the news release reported.
When pregnenolone synthesis is blocked it is believed to increase the effects of THC; when it is given a boost it blocks the "negative behavioral effects" associated with marijuana use. This experiment has only been performed on animals, but researchers believe a similar effect would be seen in humans.
"Pregnenolone cannot be used as a treatment because it is badly absorbed when administerd orally and once in the blood stream it is rapidly transformed in other steroids," researcher Pier Vincenzo Piazza, said.
The team hopes the finding will bring them a step closer to finding an effective treatment for marijuana dependence.
"We have now developed derivatives of pregnenolone that are well absorbed and stable. They then present the characteristics of compounds that can be used as new class of therapeutic drugs. We should be able to begin clinical trials soon and verify whether we have indeed discovered the first pharmacological treatment for cannabis dependence," Piazza said.