ADORA2A and attention deficit-hyperactivity disorder: A study in coloboma mice, a mouse model of ADHD (233), reported that the α2C-subtype preferring α2-AR antagonist MK912 (~10-fold selectivity over α2A-AR and α2B-AR) ameliorated NA-dependent hyperactivity (234), while α2A-AR and α2B-AR subtype-preferring drugs were ineffective.