Nutrition Bytes

Epidemiological studies have long established that smokers and coffee drinkers experience a decreased incidence of Parkinson's Disease (PD), a progressive neurodegenerative disorder for which there is no cure. Only recently have studies begun to explain these associations through plausible biological mechanisms, which in turn have helped further characterize the onset and progression of PD. Nicotinic acetylcholine receptors are present in dopaminergic neurons in the substantia nigra, and stimulation by nicotine has been shown to alleviate Parkinsonian symptoms as well as decelerate the progressive loss of dopaminergic neurons (10). A2A adenosine receptors are co-localized with dopamine receptors in GABA-ergic neurons in the striatum, and the presence of caffeine as an A2A adenosine receptor antagonist leads to symptomatic and neuroprotective benefits similar to nicotine (17). The elucidation of nicotine, caffeine, and their differing mechanisms of receptor interaction have provided valuable insights into the development of Parkinson's Disease, and may lead to novel preventive treatments and therapies.