antagonist

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antagonist

1. any muscle that opposes the action of another
2. a drug that counteracts the effects of another drug

antagonist

[an′tag·ə‚nist]
(biochemistry)
A molecule that bears sufficient structural similarity to a second molecule to compete with that molecule for binding sites on a third molecule.
(pharmacology)
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.
(physiology)
A muscle that contracts with, and limits the action of, another muscle, called an agonist, with which it is paired.
References in classic literature ?
The antagonist of Grantmesnil, instead of bearing his lance-point fair against the crest or the shield of his enemy, swerved so much from the direct line as to break the weapon athwart the person of his opponent a circumstance which was accounted more disgraceful than that of being actually unhorsed; because the latter might happen from accident, whereas the former evinced awkwardness and want of management of the weapon and of the horse.
in striking the helmet and shield of their antagonist firmly and strongly, with the lance held in a direct line, so that the weapon might break unless the champion was overthrown.
Having expressed himself thus confidently, he reined his horse backward down the slope which he had ascended, and compelled him in the same manner to move backward through the lists, till he reached the northern extremity, where he remained stationary, in expectation of his antagonist.
De Grantmesnil's horse, which was young and violent, reared and plunged in the course of the career so as to disturb the rider's aim, and the stranger, declining to take the advantage which this accident afforded him, raised his lance, and passing his antagonist without touching him, wheeled his horse and rode back again to his own end of the lists, offering his antagonist, by a herald, the chance of a second encounter.
And in the air are no streets, no channels, no point where one can say of an antagonist, "If he wants to reach my capital he must come by here.
They were declared to be aerial torpedo-boats, and the aeronaut was supposed to swoop close to his antagonist and cast his bombs as he whirled past.
Another German burnt, and one badly deflated by the prow of an antagonist, flopped out of action southward.
So it was that though Sing passed within a few paces of the unconscious man he neither saw nor heard aught of him or his antagonists.
Both Number Twelve and Number Three had assured him that the beasts had not recaptured her, for they had seen the entire band flee madly through the jungle after hearing the report of the single shot which had so terrorized Bulan's antagonists.
But as we strained and struggled about the tree into which Tars Tarkas was clambering with infinite difficulty, I suddenly caught a glimpse over the shoulder of my antagonist of the great swarm of pursuers that now were fairly upon me.
As he fell he saw a black streak shoot above him and another lion close upon his antagonist.
Kala could not understand, for the voice of Bolgani had at last been raised in the agony of suffering and death, but no sound had come to her by which she possibly could determine the nature of his antagonist.