Irreversible antagonists tend to decrease the maximal response because they reduce the number of available receptors.

Irreversible antagonists tend to decrease the maximal response because they reduce the number of available receptors.

• A. Increase
• B. No change
• C. Maximal response is unpredictable
• D. Decrease

Answer: (D)

Irreversible antagonists bind permanently to receptors, inactivating them and reducing the pool of receptors that can be activated by an agonist. With fewer available receptors, the system’s ceiling for response—its maximal effect—drops, so you can’t reach the same maximum as before. This contrasts with reversible competitive antagonists, which mainly shift the dose–response curve to require more agonist without changing the maximum. The outcome here is a decreased maximal response.

Irreversible antagonists bind permanently to receptors, inactivating them and reducing the pool of receptors that can be activated by an agonist. With fewer available receptors, the system’s ceiling for response—its maximal effect—drops, so you can’t reach the same maximum as before. This contrasts with reversible competitive antagonists, which mainly shift the dose–response curve to require more agonist without changing the maximum. The outcome here is a decreased maximal response.