Science has continually shown that people are less likely to develop Parkinsonís disease (PD) if theyíve been drinking plenty of coffee.† Studies have also found that caffeine intake could help to mitigate some of the symptoms of PD after someone has already developed the disease.†
This month, an editorial in the most recent issue of the journal Movement Disorders asks if coffee could also help to limit the uncontrollable movements called dyskinesias that are often a side effect of levodopa, the gold standard Parkinsonís drug. Research seems to say it could indeed, explains Peter Jenner, PhD, a professor of pharmacology at Londonís King College. Only, we donít really know why.†
Jenner cites a retrospective analysis of a study called CALM-PD from Anne-Marie Wills, MD, and colleagues that was also published in the latest issue of Movement Disorders, and which found that caffeine intake may lessen a personís risk of developing these levodopa-induced dyskinesias. Study authors believe that the reason this happens is related to a brain chemical called adenosine.
Adenosine is currently a target of interest in the PD field; in fact, The Michael J. Fox Foundation (MJFF) is currently supporting several projects targeting adenosine as a treatment for PD.† The bulk of the research surrounds a specific adenosine receptor called A2a, which, when inhibited, seems to enhance dopamineís effect in a particular area of the brain where dopamine has become depleted due to PD. At the same time, scientists think, the effect of another brain chemical called glutamate, which when perturbed is thought to cause a troubling side effect called dyskinesia, may also be inhibited through this process. Companies are currently looking at drugs that inhibit A2a receptors in people with PD, but itís possible that coffee also could have a similar effect to these potential drugs in development.
Thereís still a lot we donít know about why inhibiting adenosine receptors could help to alleviate a personís PD symptoms, or the dyskinesias resulting from taking Parkinsonís medication. In fact, writes Jenner, weíre not even sure if drinking coffee is preventative, or if it helps to alleviate dyskinesia and/or motor symptoms once someone is already experiencing the disease.† And Jenner suggests that the real target of focus might be a different adenosine receptor altogether, called A1. We just donít know yet.†
Still, the science is compelling. Weíll continue to keep you updated on research into adenosine in this space.