Which term describes a compound that covalently binds with the receptor, permanently blocking it from producing a signal?

Which term describes a compound that covalently binds with the receptor, permanently blocking it from producing a signal?

• A. Competitive antagonist
• B. Noncompetitive antagonist
• C. Physiological antagonist
• D. Irreversible antagonist

Answer: (D)

Permanent blockade of a receptor happens when the antagonist forms a covalent bond to the receptor, inactivating it so it can no longer transmit a signal. That covalent, irreversible attachment is the hallmark of an irreversible antagonist. Because the receptor is covalently bound, removing the drug doesn’t quickly restore function; recovery depends on making new receptors. In contrast, competitive antagonists bind reversibly to the same site and can be displaced by more agonist, while noncompetitive antagonists often bind elsewhere or impair signaling in a way that isn’t easily reversed by increasing agonist. Physiological antagonists oppose the agonist’s effect through a different system or pathway rather than by blocking the same receptor. The description given—covalent binding causing permanent receptor inactivation—best fits irreversibile antagonist.

Permanent blockade of a receptor happens when the antagonist forms a covalent bond to the receptor, inactivating it so it can no longer transmit a signal. That covalent, irreversible attachment is the hallmark of an irreversible antagonist. Because the receptor is covalently bound, removing the drug doesn’t quickly restore function; recovery depends on making new receptors. In contrast, competitive antagonists bind reversibly to the same site and can be displaced by more agonist, while noncompetitive antagonists often bind elsewhere or impair signaling in a way that isn’t easily reversed by increasing agonist. Physiological antagonists oppose the agonist’s effect through a different system or pathway rather than by blocking the same receptor. The description given—covalent binding causing permanent receptor inactivation—best fits irreversibile antagonist.