Definition of "norepinephrine" []

• A substance, C8H11NO3, both a hormone and neurotransmitter, secreted by the adrenal medulla and the nerve endings of the sympathetic nervous system to cause vasoconstriction and increases in heart rate, blood pressure, and the sugar level of the blood. Also called noradrenaline. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "This result is due to several factors: a direct release of norepinephrine from storage vesicles, the blockage of reuptake of norepinephrine once it has been released into the synaptic cleft and a decrease in norepinephrine metabolism due to inability of MAO to break down norepinephrine."
• "According to a study conducted by Alec Roy, M.D. formerly at the National Institute on Alcohol Abuse and Alcoholism, norepinephrine is secreted under stress, arousal, or thrill, so pathological gamblers gamble to make up for their underdosage."
• "Ondansetron, which indirectly blocks an adrenaline-like brain hormone called norepinephrine, appears to have fewer side effects than Inderal."