Manipulating chemicals in the brain that produce similar effects to marijuana could pave the way for a new treatment for Parkinson’s disease, scientists said on Wednesday.
When they combined a drug already used for Parkinson’s disease with a compound that boosted natural chemicals in the brain similar to the active ingredients in marijuana it relieved symptoms in genetically engineered mice with a similar illness.
“This study points to a potentially new kind of therapy for Parkinson’s disease,” said Robert Malenka of Stanford University School of Medicine in California and a co-author of the study.
“Of course, it is a long, long way to go before this will be tested in humans, but nonetheless, we have identified a new way of potentially manipulating the circuits that are malfunctioning in this disease.”
Although the natural brain chemicals called endocannabinoids are similar to those in marijuana and hashish, the scientists said their findings do not mean that smoking marijuana will ease the symptoms of Parkinson’s disease.
The previously immobile mice who were given the drug combo in the study, reported in the journal Nature, were able to move freely within 15 minutes of having the treatment.
“When we gave either drug alone we didn’t see any significant effect. But after giving the combination of the two drugs together the animals walked around almost to normal levels,” Anatol Kreitzer, a co-author of the study, said in an interview.
“It is a striking difference — about five- or six-fold increase in motor activity,” he added.
Parkinson’s disease is a progressive and irreversible neurodegenerative disease that begins with tremors and poor balance. It occurs when the cells in the brain that control movement and produce dopamine die.
Boxing legend Mohammed Ali and actor Michael J. Fox suffer from Parkinson’s.
The scientists focused their research on an area of the brain called the striatum which is also linked to depression, addiction and obsessive-compulsive disorder.
They studied different types of cells in the striatum marked with a fluorescent protein to determine what they did and how they communicated with each other.
It enabled them to identify two types of cells, which are affected by the chemical dopamine in different ways, that formed circuits involved in movement.
Too little dopamine caused difficulty in movement but when they gave the mice a drug to stimulate the chemical there was a small improvement in the rodents.
Adding another drug that boosted the activity of endocannabinoids caused a major improvement.