Which neurotransmitter plays a significant role in both central and peripheral nervous systems?

Norepinephrine is a neurotransmitter that has a vital role in both the central and peripheral nervous systems. In the central nervous system, it is involved in regulating mood, arousal, and attention, influencing various behavioral and emotional responses. In the peripheral nervous system, particularly in the sympathetic division, norepinephrine acts as a key neurotransmitter that helps mediate the "fight or flight" response. This response prepares the body for stressful situations by increasing heart rate, blood flow to muscles, and other physiological changes.

Dopamine primarily functions in the central nervous system, influencing reward, motivation, and motor control but does not have a significant role in the peripheral nervous system. Serotonin is essential for mood regulation and other functions but is more localized to the central nervous system, influencing emotional states and other homeostatic processes. GABA is the main inhibitory neurotransmitter in the central nervous system, primarily affecting neural activity and signaling within the brain and does not have a notable role in the peripheral nervous system.