(nor‵ep‵ĭ-nef'rĭn )

1. A hormone produced by the adrenal (suprarenal) medulla, similar in chemical and pharmacological properties to epinephrine but chiefly a vasoconstrictor with little effect on cardiac output.
2. A neurotransmitter released by most sympathetic postganglionic neurons and by some neurons of the brain. A disturbance in its metabolism at important brain sites has been implicated in affective disorders. It is used to manage severe hypotension, esp. in patients with neurogenic or septic shock.

n. bitartrate A stand ardized preparation of norepinephrine. The former name was levarterenol bitartrate.