Researchers from the University of East Anglia (Norfolk, United Kingdom) and University of Pompeu Fabra (Barcelona, Spain) report that they have found a way of separating the medical benefits of cannabis from its undesirable side effects in mice.

According to the World Health Organization, cannabis is a term used for denoting many psychoactive preparations of the plant Cannabis sativa. The main psychoactive compound of cannabis, also known as marijuana, is delta 9-tetrahydrocannabinol or THC. THC induces memory impairments, dependence, anxiety, etc. in marijuana users. On the other hand, THC has also been shown to reduce tumor growth in patients suffering from cancer. Additional therapeutic effects of THC include neuroprotection and muscle relaxation. This has generated a lot of medical interest for harnessing the therapeutic effects of cannabis, while keeping the cognitive side effects to a minimum.

In the study being discussed here, the research team has elegantly dissected the pathway that THC uses for bestowing psychotic effects on an individual. Their research shows that:

• The cognitive effects of THC are triggered by a pathway involving cannabinoid receptors as well as serotonin receptors.
• The pathways for the cognitive (amnesic) effects of THC are different from those for therapeutic effects; mice lacking serotonin receptors do not show amnesic effects of THC, but its analgesic effect remains intact.
• In the regions of the brain where memories are made, cannabinoid receptors and serotonin receptors work cooperatively.
• If the interaction of cannabinoid-serotonin receptors is blocked, the amnesic effect and memory deficits induced by THC are blocked, while the therapeutic effects remain intact.

“This research is important because it identifies a way to reduce some of what, in medical treatment, are usually thought of as THC’s unwanted side effects, while maintaining several important benefits including pain reduction,” says Dr. McCormick, one of the authors of the research article (as printed in University of East Anglia Press Release). He adds, “Patients should not use cannabis to self-medicate, but I hope that our research will lead to a safe synthetic equivalent being available in the future.”

Written by Mangala Sarkar, Ph.D.