Norepinephrine
Main Entry: nor·epi·neph·rine
Pronunciation: n r- ep- - nef-r n, -r n
Function: noun
: A catecholamine C8H11NO3 that is the chemical means of transmission across synapses in postganglionic neurons of the sympathetic nervous system and in some parts of the central nervous system, is a vasopressor hormone of the adrenal medulla, and is a precursor of epinephrine in its major biosynthetic pathway -- called also arterenol, nor adrenaline
Norepinephrine is a neurotransmitter in the brain that increases arousal and boosts moods. It is overabundant during mania (a severe feeling of highness), and is scarce during depression. Norepinephrine helps with emergencies: it tells the stress hormones to appear, raises blood pressure, speeds up the metabolism, raises body temperature, affects the lungs, and makes us alert and focused, basically the fight or flight response. It helps with memory and learning. All of these things are good if we're in danger, but when we just stay put every day in stress, these responses cause wear and tear on the body and we can run out of norepinephrine--and that's not good.
In humans, if norepinephrine levels stay high or spike, they may feel irritable, fear, anxiety, and even panic. High norepinephrine levels can bring on the symptoms of a panic attack, which sometimes can feel like they are coming out of the blue. Our heartbeat speeds up, our skin constricts, blood pressure increases, we may feel a loss of breath and dizziness, and our digestive system shuts down. Sometimes there are even visual disturbances.
We want norepinephrine to help us be awake and alert, but if the levels of norepinephrine don't drop down at night, we can't get restful rapid-eye-movement (REM) sleep, which is the deepest most beneficial sleep. Lack of REM sleep can have disastrous long-term consequences on mood and our whole body.
Norepinephrine plays a role in hot flashes and night sweats too. They don't have all the answers to hot flashes, but they know that luteinizing hormone (a hormone that signals the ovaries) surges (probably trying to get the missing or sleeping ovaries to DO something, ANYthing). With the surge, norepinephrine in the hypothalamus rises. The hypothalamus is trying to regulate the body's temperature and sleep. So, one of the awful things that they think might be happening is that it's the actual act of entering REM sleep--which we NEED--that triggers the hot flash. Without REM sleep, we feel tired, foggy, and depressed. So high norepinephrine can seem like depression as well as anxiety.
However, if norepinephrine levels are low, we're even more likely to be depressed. Tricyclic antidepressants work by maintaining higher levels of norepinephrine. The presence of estrogen, especially estradiol, has a mixed effect on norepinephrine levels so the effect of HRT on anxiety is unpredictable. But it's clear that the lack of estrogen has a huge effect. HRT stops the loss. The adrenal glands also produce norepinephrine, so adrenal health is important too in helping out.
Psychology 6th Edition. David G. Meyers. Nov. 5 2005. Worth Publishers. Copyright ©2001
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