While no genes for monoamine receptors, transporters, or synthesis enzymes contributed to enriched neurotransmission in the ADHD models, the gene for the inwardly rectifying potassium channel GRIK2 (KCNJ6) activated by D2 DA receptors was upregulated, and eight genes downstream of DA receptors were downregulated. This evidence concerns the gene GRIK2 and attention deficit-hyperactivity disorder.