THIS PAGE IS UNDER CONSTRUCTION There are three subtypes of adrenergic alpha-2 receptors– alpha 2A, alpha 2B, and alpha 2C. Clonidine binds to all three subtypes while guanfacine binds more selectively to alpha 2A receptors (Scahill, 2009). ADR2A is the most prevalent noradrenergic receptor in the prefrontal cortex (Arnsten et al.,1996). Related Pages References Arnsten AF….