Adenosine A(2A) Receptor Occupancy by Caffeine After Coffee Intake in Parkinson's Disease

BACKGROUND: Coffee intake can decrease the risk for Parkinson's disease (PD). Its beneficial effects are allegedly mediated by caffeine through adenosine A(2A) receptor (A(2A)R) antagonist action. OBJECTIVE: We aimed to calculate occupancy rates of striatal A(2A)Rs by caffeine after coffee intake in PD. METHODS: Five patients with PD underwent (11)C‐preladenant positron emission tomography scanning at baseline and after intake of coffee containing 129.5 mg (n = 3) or 259 mg (n = 2) of caffeine. Concurrently, serum caffeine levels were measured. RESULTS: The mean serum caffeine level (μg/mL) was 0.374 at baseline and increased to 4.48 and 8.92 by 129.5 and 259 mg of caffeine, respectively. The mean occupancy rates of striatal A(2A)Rs by 129.5 and 259 mg of caffeine were 54.2% and 65.1%, respectively. CONCLUSIONS: A sufficient A(2A)R occupancy can be obtained by drinking a cup of coffee, which is equivalent to approximately 100 mg of caffeine. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.