Dictionary > Agonist

Agonist

Definition
noun, plural: agonists
(pharmacology) A molecule that combines with a receptor on a cell to trigger physiological reaction. An example is an acetylcholine being the agonist that combines with the cholinergic receptor.
(histology) A muscle that contracts while another muscle relaxes, e.g. when bending the elbow the biceps are the agonist.
Supplement
(pharmacology) There are different kinds of agonists:

  • Full agonists have an affinity for and activate a receptor.
  • Partial agonists bind and activate a receptor but have only partial efficacy at the receptor (compared with full agonists).
  • Inverse agonists reverse constitutive activity of receptors.
  • Co-agonists work with other co-agonists to produce the desired effect together.

Word origin: From the Greek αγωνιστής (agōnistēs), contestant; champion; rival < αγων (agōn), contest, combat; exertion, struggle < αγω (agō), I lead, lead towards, conduct; drive.

Related forms: agonistic (adjective).

Related phrases: physiological agonist.

Compare: antagonist.

See also: agonism.


You will also like...

Schematic diagram of bacterial lactose operon
Gene Action – Operon Hypothesis

Learn how the way genes control and determine every aspect of the body. This lesson uses lac operon as an example. ..

..

Community Patterns

Learn about community patterns and the ecological factors influencing these patterns. Revisit some of the ecosystems you..

The Human Physiology
The Human Physiology

Physiology is the study of how living organisms function. Thus, human physiology deals specifically with the physiologic..

Digestion and Absorption of Food
Digestion and Absorption of Food

The gastrointestinal system breaks down particles of ingested food into molecular forms by enzymes through digestion and..

Developmental Biology
Developmental Biology

Developmental biology is a biological science that is primarily concerned with how a living thing grows and attains matu..

Biological Cell Defense
Biological Cell Defense

Organisms employ different strategies to boost its defenses against antigens. Humans have an immune system to combat pat..