SLC6A3 and attention deficit-hyperactivity disorder: Pandolfo et al. (2013) tested if chronic caffeine ingestion could improve certain characteristics of ADHD. In a hypertensive rat model of ADHD, they found that chronic caffeine ingestion (2°mg/kg) in ADHD rats negates neuronal circuit dysfunction, normalizes DAT density and function, and showed that the reversal of behavioral deficits in the frontal cortex related to sustained attention, all mediated by the A2A receptors.