Biomarkers

Target: Norepinephrine

Norepinephrine is the precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic. Norepinephrine is elevated in the urine of people who consume bananas. Norepinephrine is also a microbial metabolite; urinary noradrenaline is produced by Escherichia, Bacillus, and Saccharomyces (PMID: 24621061). Norepinephrine release is lowest during sleep, rises during wakefulness, and reaches much higher levels during situations of stress or danger, in the so-called fight-or-flight response.Norepinephrine is widely used as an injectable drug for the treatment of critically low blood pressure. It is classified as a sympathomimetic drug as it leads to increasing heart rate and force and constricting blood vessels.Norepinephrine is found in alcoholic beverages, banana peels and pulp (Musa paradisiaca), red plum fruit (Prunus domestica), orange pulp (Citrus sinensis), potato tubers (Solanum tuberosum), and whole purslane (Portulaca oleracea). P. oleracea is the richest of these sources. Norepinephrine has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). In adult (>18 years old) with uremia, blood levels of norepinephrine are significantly elevated at a concentration of 0.012 +/- 0.005 μM (PMID: 22626821) compared to normal adults at a concentration of 0.001 +/- 0.0004 μM (PMID: 22626821). Norepinephrine has also been identified as a biomarker for subarachnoid hemorrhage where blood concentrations of norepinephrine is significantly elevated in adults >18 years old at 0.0037 +/- 0.00048 μM (PMID: 12121816) compared to normal adults at a concentration of 0.0016 +/- 0.00012 μM (PMID: 12121816). Norepinephrine levels have also been associated with heat stress and its effects on working memory, choice reaction time and mood state (PMID: 16309771). In adults (>18 years old) with heat stress, blood norepinephrine is reduced at a concentration of 0.001 +/- 0.0013 μM (PMID: 16309771) compared to normal adults at a concentration of 0.0070 (0.0034-0.011) μM (PMID: 16324927). Additionally, norepinephrine has shown to be associated with hypothyroidism where cerebrospinal fluid levels of norepinephrine in adults (>18 years old) is shown to be significantly reduced at a concentration of 0.00005 (0.00003-0.00007) μM (PMID: 9849813) compared to normal adults at a concentration of 0.02 (0.0096-0.031) μM (PMID: 12834252).