Science finds a way for medical cannabis to relieve pain without side effects

Scientists may have developed a molecule which could allow medical cannabis to provide pain relief without any side effects.

Many people live with chronic pain, and in some cases, cannabis can provide relief. 

But the drug also can significantly impact memory and other cognitive functions. 

Now, researchers have developed a peptide that, in mice, allowed THC to fight pain without the side effects.

According to the US Centres for Disease Control and Prevention (CDC) around 20 percent of adults in the states experienced chronic pain in 2019. 

In some studies, medical cannabis has been helpful in relieving pain from migraines, neuropathy, cancer and other conditions, but the side effects can present hurdles for widespread therapeutic use.

Previously, researchers identified two peptides [molecules which are made up of amino acids] that disrupt an interaction between a receptor that is the target of THC and another that binds serotonin, a neurotransmitter that regulates learning, memory and other cognitive functions. 

When the researchers injected the peptides into the brains of mice, the mice had fewer memory problems caused by THC. 

Now, this team, led by Rafael Maldonado, David Andreu and colleagues, has gone one step further to improve these peptides to make them smaller, more stable, orally active and able to cross the blood-brain barrier.

Based on data from molecular dynamic simulations, the researchers designed two peptides that were less than half the length of the original ones but preserved their receptor binding and other functions. 

They also optimised the peptide sequences for improved cell entry, stability and ability to cross the blood-brain barrier. 

Then, the researchers gave the most promising peptide to mice orally, along with a THC injection, and tested the mice’s pain threshold and memory. 

Mice treated with both THC and the optimised peptide reaped the pain-relieving benefits of THC and also showed improved memory compared with mice treated with THC alone. 

Importantly, multiple treatments with the peptide did not evoke an immune response. 

Reporting in the American Chemical Society’s Journal of Medicinal Chemistry, researchers say that these findings suggest the optimised peptide is an ideal drug candidate for reducing cognitive side effects from cannabis-based pain management.

The abstract that accompanies this paper can be viewed here.