a hormone or neurotransmitter, CHNO, related to epinephrine, that is used medically to constrict blood vessels and to stop bleeding: it is secreted by the adrenal medulla or liberated at nerve endings to help transmit nerve impulses
Origin of norepinephrinesee nor-
A substance, C8H11NO3, both a hormone and neurotransmitter, that is secreted by the adrenal medulla and the nerve endings of the sympathetic nervous system and causes vasoconstriction and increases in heart rate, blood pressure, and the sugar level of the blood. Also called noradrenaline .
From nor- +"Ž epinephrine.