Adrenergic alpha2-Agonists

Alpha-2 adrenoceptors are G protein-coupled catecholamine receptors that activate the Gi/o pathway: they inhibit adenylyl cyclase, stimulate ERK1/2 and suppress voltage-gated calcium channels, and presynaptically they mediate feedback inhibition of noradrenaline release from sympathetic and central nerve terminals. Drugs in this class activate that receptor. The FDA-approved veterinary label for dexmedetomidine describes it as a potent non-narcotic alpha-2 adrenoceptor agonist which produces sedation and analgesia, dose dependent in depth and duration, with an initial vasopressor response followed by a compensatory marked decrease in heart rate. A drug belongs here because it activates an alpha-2 receptor; that does not exclude alpha-1 activity, and MED-RT files dexmedetomidine under the alpha-1 agonist class as well.