Serotonin metabolites suggest new human therapy pathways

This latest discovery gives cause for excitement because the enzymes that exist in mammals convert serotonin into harmless metabolites. Future treatments of nervous system disorders could exploit these pathways so that only a specific pathway in a specific tissue is affected.

The latest research titled: "Characterization of novel serotonin biochemical pathways for potential therapeutic applications,"​ appears in the August issue of the Journal of Neurochemistry​ and was presented last month at the American Chemical Society's 228th National Meeting in Philadelphia.

In the study, researchers demonstrated that in the marine mollusk, the metabolite 5-HT sulfate forms from Serotonin (5-HT) uptake and metabolism in the central ganglia but not in the hemolymph (circulatory fluid in invertebrates, comparable to the blood system in mammals). In addition 5-HT sulfate was also found in the visceral nerve and eye.

In addition, 5-hydroxyindole acetic acid, another metabolite of serotonin, while not detected in hemolymph, formed in higher quantities than 5-HT sulfate in the eye and visceral nerve. As systemic 5-HT sulfate appears not to originate from the optic region or from systemic 5-HT, the researchers concluded that 5-HT sulfate likely to derive from the nervous system.

Many pharmaceutical treatments restore the pathways by preventing the cellular uptake of serotonin, where it is converted to other metabolites, or by directly inhibiting the enzymes responsible for the molecular conversion.

The drug therapies are used to treat disruptions of serotonin signalling pathways, which are thought to occur in disorders such as depression, anxiety, sudden infant death syndrome, attention deficit hyperactivity disorder and irritable bowel syndrome.

Because serotonin is distributed throughout the body, pharmaceuticals intended