Julius Axelrod (1912-2004) was awarded one-third of the 1970 Nobel Prize in Physiology or Medicine for his work on the release, reuptake and storage of the neurotransmitters epinephrine and norepinephrine (also known as adrenaline and noradrenaline). While studying monoamine oxidase inhibitors, Axelrod discovered that, when two neurons interact with each other through a junction called synapse, epinephrine and norepinephrine are recaptured by the pre-synaptic nerve ending after being released in the synapse and recycled for later transmission. He hypothesized that epinephrine is kept in tissues in an inactive form and is released by the nervous system when needed. In addition, he found that norepinephrine could be neutralized by an enzyme, catechol-O-methyltransferase, which he named and isolated. The discovery of this enzyme proved important in understanding the nervous system and in developing psychiatric drugs.