Pharmacology The neurotransmitter secreted by postganglionic sympathetic fibers innervating sweat glands is: (Repeat) A Norepinephrine B Epinephrine C Acetylcholine D Dopamine 💡 Explanation The neurotransmitter secreted by postganglionic sympathetic fibers innervating sweat glands is: (Repeat) ✓ Correct Answer: C. Acetylcholine