Background
Alpha-1-adrenergic receptors (alpha-1-ARs) are members of the G protein-coupled receptor superfamily. There are 3 alpha-1-AR subtypes: alpha-1A, -1B and -1D, all of which signal through the Gq/11 family of G-proteins. The alpha-adrenergic receptor (AR) subtypes (alpha(1a), alpha(1b), and alpha(1d)) mediate some physiological effects of epinephrine and norepinephrine. The alpha1-AR subtypes are expressed in several organs like brain or heart in which they modulate a diversity of functional effects such as modulation of neurotransmission, vasoconstriction, etc.