agonist
Học thuậtThân thiện
Definition
- Noun:
- (Biochemistry): A substance (often a drug) that binds to a specific receptor on a cell and triggers a physiological response, mimicking the action of the body's natural substance.
- (Anatomy/Physiology): A muscle that contracts to produce a specific movement. Its action is opposed by an antagonist muscle that relaxes.
- (General): A person engaged in a struggle, contest, or conflict.
- (Literature/Drama): The main character or leading figure in a narrative, such as a play, novel, or film.
Examples of Usage
- Biochemistry:
- Morphine is an agonist that activates opioid receptors in the brain.
- This new drug is a dopamine agonist, used to treat Parkinson's disease.
- Anatomy:
- During a bicep curl, the biceps brachii is the agonist responsible for the flexion.
- The quadriceps acts as the agonist when extending the knee.
- General Contest:
- The two debaters were fierce agonists on the stage.
- Literature:
- Hamlet is the tragic agonist in Shakespeare's play.
- The novel's agonist, a young detective, drives the plot forward.
Advanced Usage
- Inverse Agonist: A type of drug that binds to the same receptor as an agonist but produces the opposite effect by reducing the receptor's baseline activity.
- Some antihistamines are inverse agonists at the histamine receptor.
- Protagonist vs. Agonist: In literary analysis, "protagonist" is the more common term for the main character. "Agonist" is used in this context to specifically emphasize the character's role in the central conflict ("agon").
- While often used interchangeably, the term 'agonist' highlights the character's struggle.
Variants and Related Words
- Antagonist (n):
- (Biochemistry): A substance that blocks or dampens a receptor's response.
- (Anatomy): A muscle that opposes the action of the agonist.
- (Literature): A character who opposes the protagonist/agonist.
- Agonistic (adj): Relating to struggle or conflict; combative.
- Protagonist (n): The leading character or one of the major characters in a story.
Synonyms
- (Biochemistry): Mimetic, activator, stimulant.
- (Anatomy): Prime mover.
- (General): Contender, combatant, adversary.
- (Literature): Protagonist, hero/heroine, main character.
Related Phrases
- Agonist-Antagonist Pair: The functional relationship between opposing muscles, such as the biceps and triceps.
- Smooth movement requires coordination within an agonist-antagonist pair.
- Full/Partial Agonist: (Biochemistry) Describes the strength of a drug's effect at a receptor. A full agonist produces the maximum response; a partial agonist produces a submaximal response even when all receptors are occupied.
Noun
- (biochemistry) a drug that can combine with a receptor on a cell to produce a physiological reaction
- a muscle that contracts while another relaxes
- when bending the elbow the biceps are the agonist
- someone involved in a contest or battle (as in an agon)
- the principal character in a work of fiction