title: Melatonin and structurally-related compounds protect synaptosomal membranes from free radical damage.
abstract: Since biological membranes are composed of lipids and proteins we tested the in vitro antioxidant properties of several indoleamines from the tryptophan metabolic pathway in the pineal gland against oxidative damage to lipids and proteins of synaptosomes isolated from the rat brain. Free radicals were generated by incubation with 0.1 mM FeCl(3), and 0.1 mM ascorbic acid. Levels of malondialdehyde (MDA) plus 4-hydroxyalkenal (4-HDA), and carbonyl content in the proteins were measured as indices of oxidative damage to lipids and proteins, respectively. Pinoline was the most powerful antioxidant evaluated, with melatonin, N-acetylserotonin, 5-hydroxytryptophan, 5-methoxytryptamine, 5-methoxytryptophol, and tryptoline also acting as antioxidants.
authors.affiliation: Department of Pharmacology and Physiology, University of Zaragoza, Spain. tarodmaul@hotmail.com
authors.forename: Sergio
authors.initials: S
authors.lastname: Millán-Plano
authors.forename: Eduardo
authors.initials: E
authors.lastname: Piedrafita
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Miana-Mena
authors.forename: Lorena
authors.initials: L
authors.lastname: Fuentes-Broto
authors.forename: Enrique
authors.initials: E
authors.lastname: Martínez-Ballarín
authors.forename: Laura
authors.initials: L
authors.lastname: López-Pingarrón
authors.forename: María A
authors.initials: MA
authors.lastname: Sáenz
authors.forename: Joaquín J
authors.initials: JJ
authors.lastname: García
mesh_terms: D006916:5-Hydroxytryptophan / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D002243:Carbolines / Q000378:metabolism; D005609:Free Radicals / Q000633:toxicity*; D007425:Intracellular Membranes / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000737:chemistry / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism; D014364:Tryptophan / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002243:Carbolines; D005609:Free Radicals; D018696:Neuroprotective Agents; D014364:Tryptophan; D006916:5-Hydroxytryptophan; D008550:Melatonin