The researchers reported that endocannabinoids, naturally occurring chemicals found in the brain that are similar to the active compounds in marijuana, helped trigger a dramatic improvement in mice with a condition similar to Parkinson's.
In the study a drug already used to treat Parkinson's disease was combined with an experimental compound that can boost the level of endocannabinoids in the brain. When they used the combination in the mice they were moving around freely in 15 minutes.
But researchers cautioned that their findings don't mean smoking marijuana could be therapeutic for Parkinson's disease.
Researchers focused on an area of the brain called the striatum. The activity of neurons in the striatum relies on the chemical dopamine and a shortage of dopamine can lead to Parkinson's disease.
In their examination of two types of mouse striatum cells, it was found that a particular form of adaptation occurs in one cell type but not in the other. One of the cells is thought to be involved in activating motion, while the other is thought to be involved in restraining unwanted movement.
When there is not enough dopamine, it seems that the cells which restrict motion become dominant, making it harder for a person to move.
The researchers tested a drug called quinpirole, which mimics dopamine, resulting in a small improvement in mice.
It was only when they added a drug that slows the enzymatic breakdown of endocannabinoids in the brain, URB597 that the results were striking. URB597 is being developed by Kadmus Pharmaceuticals.