Efaroxan hydrochloride promotes insulin secretion, at a site distinct from I1 or I2 (the putative I3 receptor) in vitro. Efaroxan hydrochloride is a potent, highly selective α2-AR adrenoceptor antagonist and imidazoline I1 receptor ligand (pKi values are 7.87, 7.42, 5.74, 7.28 and < 5 for α2A-AR , α2B-AR , α2C-AR , Ι1 and Ι2 receptors, respectively).