antagonist(redirected from a-adrenergic antagonist)
Also found in: Dictionary, Thesaurus, Medical, Legal.
Related to a-adrenergic antagonist: Adrenergic agonist
1. any muscle that opposes the action of another
2. a drug that counteracts the effects of another drug
A molecule that bears sufficient structural similarity to a second molecule to compete with that molecule for binding sites on a third molecule.
A drug or other chemical substance capable of reducing the physiological activity of another chemical substance; refers especially to a drug that opposes the action of a drug or other chemical substance on the nervous system by combining with and blocking the nerve receptor.
A muscle that contracts with, and limits the action of, another muscle, called an agonist, with which it is paired.