Role of α2-adrenergic receptors in hypertension

This is a brief review of a series of experiments conducted over the past two decades, exploring the role of the α2-adrenergic receptors (α2-AR) in salt-induced hypertension. The data suggest that salt loading alters the activity of central α2-AR, resulting in a hypertensive hyperadrenergic state. Studies to separate the role of each α2-AR subtype (α2A, α2B, and α2C) have used genetically engineered mice with disrupted genes for each subtype, or gene treatment in rats with antisense-oligodeoxynucleotides targeting a specific gene sequence. Taken together, the results of these studies indicate that the α2A-AR is centrally predominant and exerts a tonic sympathoinhibitory function, whereas peripherally it has a vasoconstrictive effect; the α2B-AR is responsible for the central hypertensive sympathoexcitatory response to salt, but is not expressed on vascular wall structures; and the α2C-AR seems to have no hemodynamic function.