Enables alpha2-adrenergic receptor activity. Involved in adenylate cyclase-inhibiting adrenergic receptor signaling pathway. Predicted to be located in membrane. Predicted to be active in plasma membrane. Is expressed in several structures, including gut; heart; integument; nervous system; and pleuroperitoneal region. Human ortholog(s) of this gene implicated in several diseases, including alcohol dependence; attention deficit hyperactivity disorder; familial partial lipodystrophy; nicotine dependence; and type 2 diabetes mellitus. Orthologous to human ADRA2A (adrenoceptor alpha 2A).