Also called norepinephrine, a hormone
produced by the medulla of the adrenal
gland. Along with adrenaline, noradrenaline
effects the fight-or-flight response. It activates the sympathetic
nervous system, which increases the concentration of glucose
in the blood, raises blood pressure and heartbeat rate, and increases muscular
power and resistance to fatigue. Noradrenaline is also one of the principal
neurotransmitters in the nervous system
where it is released from noradrenergic neurons during synaptic transmission.
An injection of noradrenaline may sometimes be given in the emrgency treatment
of shock or severe bleeding.