Adrenergic means "working onadrenaline (epinephrine) ornoradrenaline (norepinephrine)"[1][2] (or on theirreceptors). When not further qualified, it is usually used in the sense of enhancing or mimicking the effects of epinephrine and norepinephrine in the body.
Regardingproteins:
Regardingpharmaceutical drugs: