What is the primary mechanism by which cocaine produces euphoria?

• A. Increases serotonin synthesis
• B. Blocks the NMDA receptor
• C. Blocks the reuptake of dopamine
• D. Increases GABA release

Answer: (C)

Cocaine produces euphoria mainly by blocking dopamine reuptake. By inhibiting the dopamine transporter, it prevents dopamine from being cleared from the synapse, causing a surge of dopamine in the mesolimbic reward pathway, especially in the nucleus accumbens. This prolonged dopaminergic signaling strongly activates dopamine receptors and reinforces rewarding feelings, driving the euphoric experience.

Cocaine also blocks reuptake of serotonin and norepinephrine, which can contribute to mood elevation and arousal, but the intense euphoria is most directly tied to the dopamine surge in the brain’s reward circuitry.

Other mechanisms listed don’t fit the effect: increasing serotonin synthesis isn’t how cocaine works, blocking NMDA receptors isn’t its primary action, and increasing GABA release would generally dampen neural activity rather than produce the heightened reward state associated with cocaine.