Noradrenaline

Also known as norepinephrine, a hormone secreted by certain nerve endings (principally those of the sympathetic nervous system) and by the medulla (centre) of the adrenal glands. Noradrenaline’s primary function is to help maintain a constant blood pressure by way of stimulating certain blood vessels to constrict (narrow) when the blood pressure falls. For this reason, it may sometimes be injected in the emergency treatment of shock or severe bleeding. (See also adrenaline.)