Which of the following neurotransmitters is NOT released at sympathetic neuroeffector junctions?

• A. Serotonin
• B. Acetylcholine
• C. Dopamine
• D. Norepinephrine

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by understanding the sympathetic nervous system. It is part of the autonomic nervous system and is responsible for the 'fight or flight' response. Neurotransmitters released at sympathetic neuroeffector junctions play a key role in transmitting signals to target organs.
2. Step 2: Identify the primary neurotransmitters associated with the sympathetic nervous system. Norepinephrine is the main neurotransmitter released at most sympathetic neuroeffector junctions, while acetylcholine is released at preganglionic synapses.
3. Step 3: Consider dopamine. Dopamine can act as a neurotransmitter in certain sympathetic pathways, particularly in the renal system, where it influences blood flow and kidney function.
4. Step 4: Evaluate serotonin. Serotonin is primarily associated with the central nervous system and is involved in mood regulation, sleep, and appetite. It is not typically released at sympathetic neuroeffector junctions.
5. Step 5: Conclude that serotonin is the neurotransmitter that is NOT released at sympathetic neuroeffector junctions, based on its primary role in the central nervous system rather than the autonomic nervous system.