CNS depressants work by which mechanism?

• A. Inhibiting nerve impulse transmission to the CNS
• B. Stimulating CNS activity
• C. Blocking peripheral nerves only
• D. Increasing sympathetic discharge

Answer: (A)

CNS depressants reduce brain and spine activity by dampening neural signaling within the central nervous system. They typically enhance inhibitory pathways (like GABA) or suppress excitatory signaling, so nerve impulses are less likely to propagate through the CNS. This slowing of transmission leads to sedation, sleep, or anesthesia, depending on dose. That’s why the statement that CNS depressants work by inhibiting nerve impulse transmission to the CNS is the best description. They don’t primarily stimulate CNS activity, they don’t act only on peripheral nerves, and they don’t increase sympathetic discharge; in fact, they often lower overall CNS and sympathetic activity.