Epinephrine (INN) () or adrenaline (European Pharmacopoeia and BAN) (), sometimes spelled "epinephrin" or "adrenalin" respectively, is a hormone when carried in the blood and a neurotransmitter when it is released across a neuronal synapse. It is a catecholamine, a sympathomimetic monoamine derived from the amino acids phenylalanine and tyrosine. The Latin roots ad-+renes and the Greek roots epi-+nephros both literally mean "on/to the kidney" (referring to the adrenal gland, which sits atop the kidneys and secretes epinephrine). Epinephrine is sometimes shortened to epi or to EP in medical jargon.
In May 1886, William Bates reported the discovery of a substance produced by the adrenal gland in the New York Medical Journal. Epinephrine was isolated and identified in 1895 by Napoleon Cybulski, a Polish physiologist. The discovery was repeated in 1897 by John Jacob Abel.Aronson JK (2000). " Where name and image meet" - the argument for "adrenaline". British Medical Journal 320,