Definition & Meaning of "norepinephrine"

What is "norepinephrine"?

Norepinephrine is released by the adrenal glands and acts as both a hormone and a neurotransmitter. It plays a key role in the body's fight-or-flight response, mobilizing energy reserves and increasing heart rate, blood pressure, and blood flow to the muscles. Norepinephrine also affects mood, attention, and cognition, helping to enhance focus and arousal.