Lower affinity for D2 results in faster unbinding. This concept is best described as which phenomenon?

• A. Antagonism
• B. Receptor dissociation
• C. Partial agonism
• D. Dopamine transporter blockade

Answer: (B)

This is about receptor-ligand binding kinetics. Affinity tells how tightly a ligand binds, but the time it stays bound is set by the off-rate. A ligand with lower affinity tends to dissociate from the receptor more quickly, so it has a faster unbinding from the D2 receptor. That unbinding process is called receptor dissociation—the dissociation of the ligand from the receptor. The other terms describe what the ligand does while bound (antagonism blocks signaling, partial agonism provides partial activation) or a different target entirely (dopamine transporter blockade), and none of those specifically describe how fast the ligand leaves the receptor.