MAPK3 and brain disorder: On the other hand, epinephrine α2 receptor agonists could counteract hypoxia-induced brain disorders, such as clonidine, which decreases ERK1/2 expression levels and phosphorylates CREB and NF-κB and increases NR2B expression in the hippocampus by acting on NMDA receptors to phosphorylate ERK1/2 [147].