A substance that acts like another substance and therefore stimulates an action. Agonist is the opposite of antagonist. Antagonists and agonists are key players in the chemistry of the human body and in pharmacology.

A compound that is similar to LHRH (luteinizing hormone-releasing hormone) in structure and is able to it performs its action(s). Luteinizing hormone-releasing hormone is a naturally occurring hormone that controls sex hormones in both men and women. Thus, an LHRH agonist serves in a manner similar to LHRH to control the same sex hormones. An agoni [..]

A drug or substance that binds to a receptor inside a cell or on its surface and causes the same action as the substance that normally binds to the receptor.

antonym antagonist Substance which binds to cell receptors normally responding to a naturally occurring substance and which produces an effect similar to that of the natural substance. Note 1: A parti [..]

Any substance that causes a certain effect by attaching itself to the right receptor.

1876, in writings on Greek drama, from Greek agonistes, literally "combatant in the games" (see agony).

A chemical entity that binds to a receptor and activates it, mimicking the action of the natural (or abused) substance that binds there.

A ligand that binds to a receptor and alters the receptor state resulting in a biological response.

A partial agonist is an agonist that produces a maximal response that is less than the maximal response produced by another agonist acting at the same receptors on the same tissue, as a result of lowe [..]

A full agonist is an agonist that produces the largest maximal response of any known agonist that acts on the same receptor.

An inverse agonist is a ligand that by binding to a receptor reduces the fraction of receptors in an active conformation, thereby reducing basal activity. This can occur if some of the receptors are i [..]

In receptor-ligand interactions, an agonist is a molecule that binds receptor and fully induces post-receptor signalling events. The opposite of antagonist.

 A neurotransmitter, a drug or other molecule that stimulates receptors to produce a desired reaction. 

The "prime mover" or muscle of reference. agonistic behavior

noun. 1. a neurotransmitter, narcotic, chemical, or other stimulant that ties itself to a receptor spot and elicits a reaction, hence creating a physical event or modification- a narcotic which operat [..]

prime mover (pop)

An agonist is a chemical or a drug that binds to receptors in the brain and causes a reaction. A receptor is the part of a nerve that receives and reads chemical signals. It then transmits the informa [..]

A chemical substance capable of activating a given receptor.

A drug, hormone or transmitter substance that forms a complex with a receptor site that is capable of triggering an active response from a cell.

1. A molecule, usually a drug, that binds a receptor molecule and initiates a response like that of another molecule, usually a neurotransmitter. Compare antagonist (definition 1). 2. A muscle that moves a body part in the same general way as the muscle of interest; a synergistic muscle. Compare antagonist (definition 2). See also synergist.

A drug that increases neurotransmitter activity by directly stimulating the nerve cell receptors.

(n) the principal character in a work of fiction(n) someone involved in a contest or battle (as in an agon)(n) a muscle that contracts while another relaxes(n) (biochemistry) a drug that can combine w [..]

1) A substance that triggers a physiological response when it combines with a receptor. 2) A muscle whose contraction is opposed by another muscle.

Definition: (AG-on-ist) A drug that triggers an action from a cell or another drug or hormone. Compare to antagonist which blocks or nullifies an action.

An agonist is an agent, usually a pharmaceutical product, which acts to increase the normal effect of a cell. For example, an agonist that binds to a cell membrane opening enzyme may work to increase [..]

Any molecule that improves the activity of a different molecule; e.g., a hormone, which acts as an agonist when it binds to its receptor, thus triggering a biochemical response.

Illustrated Glossary of Organic Chemistry Agonist: A drug that has a strong affinity for the receptor and triggers the receptor when bound. Heroin (shown here) is an opioid receptor agonist.

Endogenous compounds and Drugs that specifically stimulate Serotonin 5-HT1 Receptors. Included under this heading are agonists for one or more of the specific 5-HT1 Receptor subtypes.

Endogenous compounds and Drugs that specifically stimulate Serotonin 5-HT2 Receptors. Included under this heading are agonists for one or more of the specific 5-HT2 receptor subtypes.

Endogenous compounds and Drugs that specifically stimulate Serotonin 5-HT3 RECEPTORS.

Endogenous compounds and Drugs that specifically stimulate Serotonin 5-HT4 RECEPTORS.

Drugs that bind to and activate Adrenergic Receptors.

Drugs that selectively bind to and activate alpha Adrenergic Receptors.

Drugs that selectively bind to and activate beta-Adrenergic Receptors.

Agents that increase Calcium influx into Calcium Channels of excitable Tissues. This causes Vasoconstriction in Vascular Smooth Muscle and/or Cardiac Muscle Cells as well as stimulation of Insulin rel [..]

Drugs that bind to and activate Cholinergic Receptors.

Drugs that bind to and activate Dopamine Receptors.

Drugs that bind to and activate Excitatory Amino Acid receptors.

Endogenous compounds and Drugs that bind to and activate GABA-A Receptors.

Endogenous compounds and Drugs that bind to and activate GABA-B Receptors.

Endogenous compounds and Drugs that bind to and activate gamma-Aminobutyric Acid Receptors (Receptors, GABA).

Drugs that bind to and activate Histamine Receptors. Although they have been suggested for a variety of clinical applications Histamine agonists have so far been more widely used in Research than ther [..]

Drugs that bind to and activate muscarinic Cholinergic Receptors (Receptors, Muscarinic). Muscarinic agonists are most commonly used when it is desirable to increase Smooth Muscle tone, especially in [..]

Agents that destroy Bone Marrow activity. They are used to prepare Patients for Bone Marrow Transplantation or Stem Cell Transplantation.

Drugs that bind to and activate nicotinic Cholinergic Receptors (Receptors, Nicotinic). Nicotinic agonists act at postganglionic Nicotinic Receptors, at Neuroeffector Junctions in the Peripheral Nervo [..]

Endogenous compounds and Drugs that bind to and activate Serotonin Receptors. Many Serotonin receptor agonists are used as Antidepressants; Anxiolytics; and in the treatment of Migraine Disorders.

A drug or other chemical that can bind to a receptor or cell to trigger a response typical of a naturally occurring substance.

a drug that increases neurotransmitter activity by stimulating the receptors of a neurotransmitter directly.

1.) A neurotransmitter, drug, or other molecule that stimulates receptors to produce a desired reaction. 2.) A muscle that moves a joint in an intended direction.

A drug that triggers an action from a cell or another drug.

Substance which changes the properties of cells via receptors at the cell membranes.

A ligand that binds a receptor at a site adjacent to the active site.

1. <anatomy> A prime mover. 2. <pharmacology> A drug that has affinity for and stimulates physiologic activity at cell receptors normally stimulated by naturally occurring substances, thus triggering a biochemical response. (18 Nov 1997)

A drug which binds to a receptor and activates it, producing a pharmacological response (e.g. contraction, relaxation, secretion, enzyme activation, etc.).

An agent that has affinity for a receptor and intrinsic activity at that receptor.

Someone involved in a contest or battle (as in an agon). The muscle that contracts while the other relaxes. ''When bending the elbow, the biceps is the agonist.'' (biochemistry) A molecule tha [..]

A drug that imitates a neurotransmitter. Dopamine agonists are drugs that imitate the