Have high affinity for pre and postsynaptic D2 and 5-HT1a receptors. This property is typical of which drug class?

• A. Antagonists
• B. Inverse agonists
• C. Partial agonists
• D. Reuptake inhibitors

Answer: (C)

The key idea is how partial agonists work. A drug class that binds with high affinity to both presynaptic autoreceptors and postsynaptic D2 receptors, as well as to 5-HT1A receptors, and activates them only partially, fits partial agonists. Because these agents produce a submaximal receptor response, they can modulate dopamine and serotonin signaling rather than fully block it. Activation of presynaptic D2 autoreceptors reduces dopamine synthesis and release, while activation of postsynaptic D2 receptors modulates downstream signaling; a partial agonist at both sites can dampen excessive dopaminergic activity when the system is overactive and maintain activity when it’s low. Simultaneously, partial agonism at 5-HT1A receptors contributes to mood and anxiety effects, aligning with the profile of drugs that stabilize symptoms rather than produce full antagonism. An example is aripiprazole, known for D2 and 5-HT1A partial agonism. Thus, this binding and functional profile is characteristic of partial agonists.