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Guilherme Mazui

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What is the Difference Between Inverse Agonist and Antagonist?

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The main difference between inverse agonists and antagonists lies in their effects on receptor activity:

  • Inverse Agonists: These drugs bind to the same receptor-binding site as agonists but produce an effect opposite to that of an agonist. Inverse agonists decrease the constitutive receptor activity, and they can be classified as "full" or "partial" inverse agonists, depending on the degree of their effects. They can also be seen as decreasing the number of active receptors and decreasing signaling, thus behaving as an antagonist.
  • Antagonists: These drugs produce no effect on their own but block the effects of both agonists and inverse agonists. Antagonists bind to the receptor with equal affinity to both active and inactive states, and they do not change the ongoing receptor-mediated response. However, they occupy the receptor population and can reduce the inverse agonist component.

In summary, inverse agonists produce an effect opposite to that of an agonist, while antagonists block the effects of both agonists and inverse agonists without producing any effect on their own.

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  • What is the Difference Between Inverse Agonist and Antagonist?
  • Comparative Table: Inverse Agonist vs Antagonist

    • Comparative Table: Inverse Agonist vs Antagonist

    Here is a table comparing the differences between inverse agonists and antagonists:

    Feature Inverse Agonist Antagonist
    Definition A drug that binds to the same receptor as an agonist but decreases the activity below the basal level. A drug that binds to a receptor and prevents the binding of agonists or inverse agonists, returning the receptor to its basal activity.
    Effect on Receptor Decreases the activity of a particular receptor above its basal level. Returns the receptor to its basal activity.
    Activity in the Absence of Ligand Requires a receptor with a constitutive level of activity without any ligand. Can bind to receptors with or without a constitutive level of activity.
    Types of Antagonists None Competitive antagonists, non-competitive antagonists, uncompetitive antagonists, and silent antagonists.
    Examples ABAA, muopioid, histamine, melanocortin, and beta-adrenergic receptors. Phenoxybenzamine, an irreversible antagonist (alpha-blocker).
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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.