agonist

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agonist

 [ag´o-nist]
in pharmacology, a drug that has affinity for the cellular receptors of another drug or natural substance and that produces a physiological effect.

ag·o·nist

(ag'on-ist),
1. Denoting a muscle in a state of contraction, with reference to its opposing muscle, or antagonist.
2. A drug capable of combining with receptors to initiate drug actions; it possesses affinity and intrinsic activity.
[G. agōn, a contest]

agonist

(ăg′ə-nĭst)
n.
1. Physiology A contracting muscle that is resisted or counteracted by another muscle, the antagonist.
2. A substance that can combine with a receptor on a cell to initiate signal transduction.

Agonist

Anatomy Agonist muscle, prime mover. A muscle that causes a particular movement to occur, creating a normal range of movement in a joint by contracting; a muscle which moves in one general direction.
Molecular biology A ligand which binds a receptor at a site adjacent to the active site.
Pharmacology Agonist medication. A chemical entity that does not naturally occur in the body and acts on one or more receptors (e.g., mu, delta, and kappa opiate receptors) by structural mimicry of the receptors’ natural ligand(s). It may be an agonist or partial agonist for a particular receptor, promoting a receptor-mediated biological response, often by competing with another substance (usually the natural or native substance) at the same receptor. A partial agonist produces less than the maximum effect even if given in a concentration sufficient to bind with all available receptors.

agonist

Pharmacology A substance that promotes a receptor-mediated biologic response, often by competing with another substance at the same receptor. Cf Antagonist.

ag·o·nist

(ag'ŏn-ist)
1. A muscle (or group of muscles) whose contraction produces a specific action with reference to its antagonist muscle (or muscles).
2. A drug capable of combining with receptors to initiate drug actions; it possesses affinity and intrinsic activity.
[G. agōn, a contest]

agonist

1. A molecule, such as a HORMONE, NEUROTRANSMITTER or drug, that attaches (binds) to a cell receptor site to produce an effect on the cell. Many drugs are agonists having an effect similar or identical to natural body agonists. Other drugs act on the receptor in a blocking role and are antagonists. An antagonist is a molecule that interferes with or prevents the action of the agonist.
2. A contracting muscle that is opposed by contraction of another associated muscle, the antagonist.

agonist

  1. a substance capable of binding to a molecular target on the cell surface (RECEPTOR) to elicit a biological response. Examples include HORMONES and DRUGS.
  2. a muscle which initiates a response or change in position of a body part acting against an ANTAGONISTIC MUSCLE.

Agonist

A medication that has an affinity for and stimulates the activity of cell receptors that are normally stimulated by naturally occurring substances, including melatonin.

agonist 

1. An agonistic muscle.
2. A substance (e.g. a drug, hormone or neurotransmitter) that binds with a cell receptor to initiate a physiological response similar to that produced by the natural neurotransmitter or hormone. Example: pilocarpine, which mimics the effect of acetylcholine acting on cholinergic receptors. See antagonist.

ag·o·nist

(ag'ŏn-ist)
1. Denoting a muscle in a state of contraction, with reference to its opposing muscle, or antagonist.
2. A drug capable of combining with receptors to initiate drug actions; it possesses affinity and intrinsic activity.
[G. agōn, a contest]
References in periodicals archive ?
The unique presynaptic 5-HT1A partial agonism of vilazodone is similar to that of buspirone, in which both drugs initially inhibit serotonin synthesis and neuronal firing.
Aripiprazole's proposed mechanism of action on dopamine receptors is that of partial agonism, (1) rather than antagonism, as is the case for other SGAs.
Similar to all antidepressants, vilazodone's mechanism of action is not fully understood, but is thought to be related to its inhibition of serotonin (ie, 5-HT) reuptake and partial agonism of 5-HT1A receptors.