Biosynthesis of NE
Phenylalanine → Tyrosine → L-DOPA → Dopamine → Norepinephrine
That flight or fight response is all about norepinephrine (NE), noradrenaline (NA) and it’s known as both a hormone and a brain neurotransmitter. NE is mainly stored in the neurons (nerve cells) of the sympathetic nervous system with small amounts also stored in adrenal tissue, which lay on top of your kidneys.
As a neurotransmitter, NE passes nerve impulses from one neuron to the next. It’s the primary neurotransmitter in the sympathetic nervous system where it works on the activity of various organs in the body to control blood pressure, heart rate, liver function, and many other functions.
As a hormone, norepinephrine is released into the bloodstream by the adrenal glands and works alongside adrenaline (also known as epinephrine) to give the body sudden energy in times of stress, known as the “fight or flight” response.
Cell bodies of most NE neurons are located in regions of the pons and medulla and the thalamus
Locus coeruleus in the pons – activation leads to increased vigilance and arousal. Targeting NE receptors help with chronic pain and vasomotor symptoms, sexual side effects, and depression. N-E Pain (mnemonic)
Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)
Medications that inhibit the reuptake of norepinephrine and serotonin (which is another neurotransmitter) are called serotonin-norepinephrine reuptake inhibitors (SNRIs). By inhibiting the reuptake of these two neurotransmitters, SNRIs are essential to increasing the levels of norepinephrine and serotonin in the brain. Serotonin makes a person feel good and norepinephrine improves energy and attentiveness.
SNRIs have been found to be effective in treating mood disorders like depression, bipolar disorder, and anxiety disorders. SNRIs are also sometimes prescribed for chronic pain and fibromyalgia.
