Which pairing correctly matches autonomic division to its primary transmitter?

• A. Sympathetic — Norepinephrine; Parasympathetic — Acetylcholine
• B. Sympathetic — Acetylcholine; Parasympathetic — Norepinephrine
• C. Sympathetic — Dopamine; Parasympathetic — Serotonin
• D. Sympathetic — GABA; Parasympathetic — Glutamate

Answer: (A)

Postganglionic transmitters distinguish the autonomic divisions. In the sympathetic pathway, the postganglionic neuron releases norepinephrine to act on adrenergic receptors throughout the body, preparing for rapid, energy‑saving responses. In the parasympathetic pathway, the postganglionic neuron releases acetylcholine to act on muscarinic receptors, promoting slower, restorative activities. Since these are the primary transmitters used by the two divisions for their target organs (with acetylcholine used at the preganglionic synapses for both), pairing sympathetic with norepinephrine and parasympathetic with acetylcholine reflects the standard pattern. There are occasional exceptions, such as sympathetic nerves to sweat glands using acetylcholine, but for the general rule tested here, the described pairing is correct. Transmitters like dopamine, serotonin, GABA, or glutamate are not the typical postganglionic transmitters of either division.