antagonist

Examples of antagonist in the following topics:

• Blocking of Hormone Receptors

  • Once bound, an antagonist will block agonist binding.
  • The term "non-competitive antagonism" (sometimes called non-surmountable antagonists) can be used to describe two distinct phenomena: one in which the antagonist binds to the active site of the receptor, and one in which the antagonist binds to an allosteric site of the receptor.
  • The second form of "non-competitive antagonists" act at an allosteric site.
  • Uncompetitive antagonists differ from non-competitive antagonists in that they require receptor activation by an agonist before they can bind to a separate allosteric binding site.
  • Many antagonists are reversible antagonists that, like most agonists, will bind and unbind a receptor at rates determined by receptor-ligand kinetics.

• How Skeletal Muscles Produce Movements

  • Muscles are arranged in groupings of agonist, antagonist, and synergists that produce and modulate movement.
  • The biceps and triceps muscle groups are an example of an agonist/antagonist pair.
  • During extension, the triceps act as the agonist while the biceps act as the antagonist.
  • The majority of muscles are grouped in pairs, with an antagonist to each agonist muscle.
  • The triceps brachii (not shown) acts as the antagonist.

• Agonists, Antagonists, and Drugs

  • Drugs acting on the acetylcholine system are either agonists to the receptors, stimulating the system, or antagonists, inhibiting it.
  • Agonists increase the level of receptor activation, antagonists reduce it.
  • Beta blockers (sometimes written as β-blockers) or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications.
  • As beta adrenergic receptor antagonists, they diminish the effects of epinephrine (adrenaline) and other stress hormones.
  • Distinguish between the effects of an agonist versus an antagonist in the autonomic nervous system

• Interactions of Hormones at Target Cells

  • Hormones that act to return body conditions to within acceptable limits from opposite extremes are called antagonistic hormones.
  • Hormones that act to return body conditions to within acceptable limits from opposite extremes are called antagonistic hormones.
  • The regulation of blood glucose concentration (through negative feedback) illustrates how the endocrine system maintains homeostasis by the action of antagonistic hormones.
  • These cells control blood glucose concentration by producing the antagonistic hormones insulin and glucagon.

• Electrophilic Substitution of Disubstituted Benzene Rings

  • Thus, the groups may be oriented in such a manner that their directing influences act in concert, reinforcing the outcome; or are opposed (antagonistic) to each other.
  • The products from substitution reactions of compounds having a reinforcing orientation of substituents are easier to predict than those having antagonistic substituents.
  • Substitution reactions of compounds having an antagonistic orientation of substituents require a more careful analysis.

• Divisions of the Autonomic Nervous System

  • This opposition is often viewed as complementary in nature rather than antagonistic.
  • More generally, these two systems should be seen as permanently modulating vital functions, in usually antagonistic fashion, to achieve homeostasis.

• Autonomic Interactions

  • However, this opposition is better termed complementary in nature rather than antagonistic.
  • More generally, these two systems should be seen as permanently modulating vital functions, in usually antagonistic fashion, to achieve homeostasis.

• The Speech to Secure Goodwill

  • Speeches to secure goodwill seek to forge new relationships between previously unknown, antagonistic, or unfamiliar entities.

• Overview of the Parathyroid Glands

  • PTH has effects antagonistic to those of calcitonin by increasing blood calcium levels by stimulating osteoclasts to break down bone and release calcium.

• Auxins, Cytokinins, and Gibberellins

  • The hormones can act in their cell of origin or be transported to other portions of the plant body, with many plant responses involving the synergistic or antagonistic interaction of two or more hormones.
  • In urban areas, GA antagonists are sometimes applied to trees under power lines to control growth and reduce the frequency of pruning.
  • Abscisic acid is a strong antagonist of GA action.