ADORA2A and Alzheimer disease: These effects are exclusively due to the blockade of A1 and A2ARs (and not of other actions, e.g., release of intracellular Ca2+, elicited by toxic concentrations of caffeine only), although the modulation of synaptic plasticity, and the beneficial effects of caffeine in the neurogenerative illnesses AD and PD are caused by A2AR inhibition [48, 49, 132, 141, 142].