Putative endogenous neurotransmitter at imidazoline receptors; displaces clonidine at α2-adrenergic and at imidazoline receptors; blocks NMDA-activated ion channels in hippocampal neurons.
(+)-Isomer is a selective α-adrenoceptor antagonist; (−)-isomer is an imidazoline ligand that induces insulin secretion, mediated by the blockade of ATP-sensitive potassium channels in pancreatic β cells; I1 imidazoline binding site antagonist.