Norepinephrine

Norepinephrine is also known as noradrenaline and it is a catecholamine and a phenethylamine. It is released from the medulla of the adrenal glands as a hormone. It is also a neurotransmitter in the central nervous system and sympathetic nervous system. It functions as a stress hormone along with epinephrine, and it is partially responsible for the fight-or-flight response. It directly increasing heart rate, triggers the release of glucose from energy stores, and increases skeletal muscle readiness.