Pronunciation: (nôr"ep-u-nef'rin, -rēn),[key] —n. 1. Also called noradrenaline.Physiol.a neurotransmitter, released by adrenergic nerve terminals in the autonomic and possibly the central nervous system, that has such effects as constricting blood vessels, raising blood pressure, and dilating bronchi.
2. Pharm.a commercial form of this substance used for emergency treatment of lowered blood pressure.