Which term describes a drug that increases the effects of a neurotransmitter by mimicking the neurotransmitter or promoting its release?

• A. Antagonist
• B. Inhibitor
• C. Agonist
• D. Blocker

Answer: (C)

An agonist is the term for a drug that increases the effects of a neurotransmitter by binding to its receptors and triggering the same response as the natural ligand. By mimicking the neurotransmitter or promoting its release, an agonist enhances signaling at the synapse, leading to a stronger or more prolonged effect.

An antagonist, by contrast, binds to receptors but blocks activation, reducing signaling. An inhibitor lowers the activity of enzymes or transporters, which can change neurotransmitter levels, but it doesn’t directly activate receptors. A blocker generally refers to something that obstructs receptor or channel function rather than activating it.