agonist

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noun ag·o·nist \ ˈa-gə-nist \

Definition of agonist

1 :one that is engaged in a struggle

[from antagonist]

a :a muscle that is controlled by the action of an antagonist with which it is paired

b :a chemical substance capable of combining with a specific receptor on a cell and initiating the same reaction or activity typically produced by the binding endogenous substance

dopaminergic agonists

— compare antagonist 2b

Recent Examples of agonist from the Web

This agonist-antagonist muscle pair allowed the body to sense the stretch, torque and speed of a muscle in a realistic way, electrical measurements showed, and in theory, would allow more control over a prosthetic limb.

— karen weintraub, Scientific American, "New Approach to Amputation Could Reduce Phantom Pain," 2 June 2017
Trevena is already studying a compound that acts as a biased-agonist at the delta-opioid receptor as a possible migraine headache medication, according to Violin.

— jon kelvey, Smithsonian, "America’s Long-Overdue Opioid Revolution Is Finally Here," 13 Jan. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'agonist.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of agonist

Late Latin agonista competitor, from Greek agōnistēs, from agōnizesthai to contend, from agōn

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First Known Use: 1658

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Medical Dictionary

agonist

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noun ag·o·nist \ ˈag-ə-nəst \

medical Definition of agonist

1 :a muscle that on contracting is automatically checked and controlled by the opposing simultaneous contraction of another muscle — called also agonist muscle, prime mover; compare antagonist a, synergist 2

2 :a chemical substance (as a drug) capable of combining with a receptor on a cell and initiating the same reaction or activity typically produced by the binding of an endogenous substance