from The American Heritage® Dictionary of the English Language, 4th Edition
- n. 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.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A neurotransmitter found in the locus coeruleus which is synthesized from dopamine.
from the GNU version of the Collaborative International Dictionary of English
- n. A hormone (C8H11NO3) secreted by the adrenal medulla; it also serves as a neurotransmitter, released at synapses; called also noradrenaline. Chemically it is 2-amino-1-(3,4-dihydroxyphenyl)ethanol. It is a precursor of epinephrine in the body.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a catecholamine precursor of epinephrine that is secreted by the adrenal medulla and also released at synapses
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.
He then went on to study the release of norepinephrine from the adrenergic neurons in the ear artery by cholinergic agonists acting on prejunctional nicotinic receptors.
When blood pressure could not be maintained with a dose of 20 µg per kilogram of body weight per minute for dopamine or a dose of 0.19 µg per kilogram per minute for norepinephrine, open-label norepinephrine, epinephrine, or vasopressin could be added.
Opiates also inhibit the production of a chemical messenger called norepinephrine, which is thought to enhance fear signals in the brain.
Extreme emotions trigger the release of a chemical in the brain called norepinephrine, which is related to adrenaline.
She thinks that these low levels contribute to an accelerated breakdown of the hormone norepinephrine, which is involved in regulating the body's response to stress -- its "fight or flight" response.
In the older, survival part of your brain, a type of adrenaline called norepinephrine triggers the fight-or-flight response, which takes many different forms today.
There's now a drug -- these newer drugs are working on not just serotonin but also norepinephrine, which is another brain chemical responsible for mood.