Protective Agents in Parkinson's Disease: Caffeine and Adenosine A2A Receptor Antagonists

The pharmacologic management of Parkinson’s disease is based on drugs that act on the motor symptoms, whereas there are currently no drugs available that can alter the progressive neurodegeneration of dopaminergic neurons. Based on recent findings suggesting that the adenosinergic system is one of the most interesting in the field of neuroprotection in Parkinson’s disease, this chapter describes the functions of adenosine and its receptors in the central nervous system, with particular emphasis on their role in neurotoxicity/neuroprotection. Results of epidemiologic surveys demonstrating that intake of caffeine, an adenosine A1/A2A receptor antagonist, is inversely correlated with Parkinson’s disease are summarized. Moreover, evidence originating from preclinical studies showing that the antagonism of the adenosine A2A receptor is responsible for the neuroprotective effects of caffeine is also presented. This chapter therefore provides a comprehensive analysis of the current literature concerning the adenosinergic-based neuroprotective intervention strategy for Parkinson’s disease.