title: Serotonin as a putative scavenger of hypohalous acid in the brain.
abstract: Neurodegenerative disorders represent the culmination of numerous insults including oxidative stress. The long etiology of most of these disorders suggests that lessening the effects of one or more of the insults could significantly delay disease onset. Antioxidants have been tested as possible therapeutics for neurodegenerative disorders, but with little success. Here we report that serotonin acts as a scavenger of hypochlorous acid (HOCl) in the brain. Serotonin was shown to prevent the oxidation of 2-thio-5-nitrobenzoate by HOCl in a biphasic manner. The first phase was a partial scavenging that occurred at concentrations of serotonin that exceeded those of HOCl. (1)H-NMR studies indicated that HOCl chlorinates both the aryl and akyl nitrogen atoms of serotonin. Thus, the oxidation of 2-thio-5-nitrobenzoate that occurred during the first phase of scavenging is likely due to the formation of serotonergic chloramines. A second phase of scavenging occurred at concentrations of HOCl that exceeded those of serotonin. Under these conditions, the chlorinated serotonin polymerized and formed inert aggregates. Serotonin was further shown to prevent the loss of cells and cellular α-ketoglutarate dehydrogenase complex activity caused by HOCl. Extracellular concentrations of serotonin in the brain can be elevated with selective serotonin reuptake inhibitors and suggests that such compounds could be used to increase the cerebral antioxidant capacity. Acute administration of selective serotonin reuptake inhibitors to mice treated with endotoxin partially mitigated sickness behavior and protein chlorination in the brain. These observations suggest that serotonin may act to suppress chlorinative stress in the brain.
authors.affiliation: Department of Neurosciences, Winthrop University Hospital, 222 Station Plaza, Mineola, NY 11501, USA. Electronic address: mike.m.kalogiannis@hofstra.edu.
authors.forename: Mike
authors.initials: M
authors.lastname: Kalogiannis
authors.affiliation: Department of Radiology, University of Pennsylvania, 317 Anatomy Chemistry Building, 3620 Hamilton Walk, Pennsylvania, PA 19104, USA. Electronic address: delikatn@mail.med.upenn.edu.
authors.forename: E James
authors.initials: EJ
authors.lastname: Delikatny
authors.affiliation: Department of Neurosciences, Winthrop University Hospital, 222 Station Plaza, Mineola, NY 11501, USA; Department of Biochemistry and Molecular Biology, New York Medical College, Basic Sciences, 15 Dana Road, Valhalla, NY 10595, USA. Electronic address: Thomas_Jeitner@nymc.edu.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jeitner
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D016166:Free Radical Scavengers / Q000378:metabolism* / Q000494:pharmacology; D054879:Halogenation; D006801:Humans; D006997:Hypochlorous Acid / Q000378:metabolism*; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism; D008297:Male; D051379:Mice; D018384:Oxidative Stress; D012701:Serotonin / Q000378:metabolism* / Q000494:pharmacology; D000074084:THP-1 Cells
chemical_list: D016166:Free Radical Scavengers; D012701:Serotonin; D006997:Hypochlorous Acid; D007655:Ketoglutarate Dehydrogenase Complex
keywords: Antioxidant; Brain; Hypochlorous acid; Myeloperoxidase; Neurodegenerative diseases; Serotonin