agonist
noun
ag·o·nist ˈa-gə-nist 
1
: one that is engaged in a struggle
2
[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 sense 2b 
Example Sentences
Recent Examples on the Web Autobahn’s drug candidate is a thyroid hormone receptor beta agonist, which the company says could have uses beyond treatment-resistant depression. 
Mike Freeman, San Diego Union-Tribune, 9 Sep. 2022 While its exact recipe is proprietary, the adjuvant contains something called a TLR7/8 agonist: small molecules that stimulate immune cells to activate an immune response. Wired, 28 July 2022 Some men have had an increase in the blood pressure with mirabegron (the other available beta-3 agonist), so that is worth keeping an eye on. Dr. Keith Roach, oregonlive, 30 June 2022 The inhaler will contain medication to keep your lungs from going haywire, like a short-acting beta-agonist to open up your airways. Ashley Abramson, SELF, 26 May 2022 In June of last year, the Food and Drug Administration (FDA) approved Novo Nordisk’s obesity drug Wegovy, a GLP-1 receptor agonist, which is also administered once-weekly through subcutaneous injection. Joshua Cohen, Forbes, 1 May 2022 Methadone is an opioid agonist that reduces cravings and withdrawal symptoms by activating opioid receptors. Sarah Fielding, Health.com, 17 Nov. 2021 The most common treatments for acute migraine include the triptan (selective 5-hydroxytryptamine serotonin receptor agonist) class of medicines. Joshua Cohen, Forbes, 3 Oct. 2021 Opioid agonist therapies, including methadone and suboxone, can also suppress testosterone. Alia E. Dastagir, USA TODAY, 23 July 2021 See More
Mike Freeman, San Diego Union-Tribune, 9 Sep. 2022 While its exact recipe is proprietary, the adjuvant contains something called a TLR7/8 agonist: small molecules that stimulate immune cells to activate an immune response. Wired, 28 July 2022 Some men have had an increase in the blood pressure with mirabegron (the other available beta-3 agonist), so that is worth keeping an eye on. Dr. Keith Roach, oregonlive, 30 June 2022 The inhaler will contain medication to keep your lungs from going haywire, like a short-acting beta-agonist to open up your airways. Ashley Abramson, SELF, 26 May 2022 In June of last year, the Food and Drug Administration (FDA) approved Novo Nordisk’s obesity drug Wegovy, a GLP-1 receptor agonist, which is also administered once-weekly through subcutaneous injection. Joshua Cohen, Forbes, 1 May 2022 Methadone is an opioid agonist that reduces cravings and withdrawal symptoms by activating opioid receptors. Sarah Fielding, Health.com, 17 Nov. 2021 The most common treatments for acute migraine include the triptan (selective 5-hydroxytryptamine serotonin receptor agonist) class of medicines. Joshua Cohen, Forbes, 3 Oct. 2021 Opioid agonist therapies, including methadone and suboxone, can also suppress testosterone. Alia E. Dastagir, USA TODAY, 23 July 2021 See More Word History
Etymology
borrowed from Late Latin agōnista, borrowed from Greek agōnistḗs, from agōnízesthai "to contend, fight" + -istēs -ist entry 1 — more at agonize
First Known Use
1658, in the meaning defined at sense 1
Medical Definition
agonist
noun
ag·o·nist ˈag-ə-nəst
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 sense a, synergist sense 22
: 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
binding of adrenergic agonists
compare antagonist sense b