Norepinephrine is a chemical (neurotransmitter) in the brain that sends messages from one area of the brain to another. This chemical is associated with arousal, attention and mood. It regulates or "fight or flight" response.
Norepinephrine is a neurotransmitter or chemical messenger that helps to relay messages from one area of the brain to another. It is involved with arousal, attention and mood. In the body, it is involved with the "fight or flight response."