What neurotransmitter do sympathetic boutons primarily secrete?

What neurotransmitter do sympathetic boutons primarily secrete?

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

Answer: (C)

Sympathetic boutons primarily secrete norepinephrine, which is the primary neurotransmitter of the sympathetic nervous system. This neurotransmitter is responsible for initiating the "fight or flight" response, preparing the body for action by increasing heart rate, redirecting blood flow to muscles, and releasing energy stores. Norepinephrine works by binding to adrenergic receptors on target organs, leading to various physiological responses that support heightened alertness and physical readiness.

In contrast, acetylcholine is primarily associated with the parasympathetic nervous system and plays a key role in promoting rest and digest functions. Dopamine, while an important neurotransmitter in the brain affecting mood and motor control, is not typically released by sympathetic boutons. Serotonin is mainly involved in regulating mood, sleep, and other functions but is not secreted by sympathetic nerve endings. Hence, the unique role of norepinephrine in activating the sympathetic response is what makes it the correct answer here.