Cannabis could provide relief to stroke patients

Some mechanisms in the brain targeted by cannabis have been found to have potentials in countering brain cell damage after a stroke.

New research by scientists at the University of Otago in New Zealand has shown that the cannabinoid CB2 receptor appears in the rat brain following a stroke. The findings have been touted as a world-first, and were published recently in the international journal Neuroscience Letters.

The CB2 receptor is a protein produced in response to stroke as part of the body's immune response system. This response causes the inflammation that leads to damage in the area of the brain around where the stroke has occurred, according to John Ashton, a medical researcher at the University’s Department of Pharmacology and Toxicology.

"If the inflammation can be stopped or reduced then it offers the hope of reducing the extent of the damage caused by stroke - and CB2 offers a potential target for such a drug,” he said.

Ashton explained that the active ingredient of cannabis, THC, targets both the CB2 and the related CB1 receptors. But while THC has been known to have some positive effects for pain management, its use is currently severely limited because of how it triggers the psychoactive CB1 receptors in the brain.

"The aim would be to develop a drug that targets the CB2 receptor without affecting CB1," Ashton said, suggesting a pharmaceutical approach similar to that that has already been taken to develop codeine from heroin.

"Heroin and codeine share common targets, but by designing codeine in such a way that it eliminated the psychoactive side-effects seen with heroin, a therapeutically useful drug was developed. There is the potential to do the same with cannabinoids," he said.

Drugs targeting CB2 could also have potential therapeutic use in other conditions involving inflammatory damage to the brain, such as Huntington's Disease and Alzheimer's Disease. There may also be scope to use them in pain management.

More information is available from the University of Otago’s press release.