Possible role of serotoninergic system in the neurobehavioral impairment induced by acute methylmercury exposure in zebrafish ( Danio rerio )

• Published in: Neurotoxicology and teratology 2011-11, Vol.33 (6), p.727-734
• Main Authors: Maximino, Caio, Araujo, Juliana, Leão, Luana Ketlen Reis, Grisolia, Alan Barroso Araújo, Oliveira, Karen Renata Matos, Lima, Monica Gomes, Batista, Evander de Jesus Oliveira, Crespo-López, Maria Elena, Gouveia, Amauri, Herculano, Anderson Manoel
• Format: Article
• Language: English
• Subjects: Animals; Anxiety; Anxiety - chemically induced; Anxiety - metabolism; Anxiety - physiopathology; Behavior, Animal - drug effects; Brain - drug effects; Brain - metabolism; Chromatography, High Pressure Liquid; Danio rerio; Disease Models, Animal; Dose-Response Relationship, Drug; Emergency; Female; Freshwater; Lipid Peroxidation - drug effects; Male; Medical Education; Mercury Poisoning, Nervous System - physiopathology; Methylmercury; Methylmercury Compounds - toxicity; Oxidative stress; Oxidative Stress - drug effects; Serotonin; Serotonin - metabolism; Subcellular Fractions - metabolism; Zebrafish; Zebrafish - metabolism; Zebrafish - physiology
• ISSN: 0892-0362; 1872-9738
• DOI: 10.1016/j.ntt.2011.08.006

Abstract Adult zebrafish were treated acutely with methylmercury (1.0 or 5.0 μg g − 1 , i.p.) and, 24 h after treatment, were tested in two behavioral models of anxiety, the novel tank and the light/dark preference tests. At the smaller dose, methylmercury produced a marked anxiogenic profile in both tests, while the greater dose produced hyperlocomotion in the novel tank test. These effects were accompanied by a decrease in extracellular levels of serotonin, and an increase in extracellular levels of tryptamine-4,5-dione, a partially oxidized metabolite of serotonin. A marked increase in the formation of malondialdehyde, a marker of oxidative stress, accompanied these parameters. It is suggested that methylmercury-induced oxidative stress produced mitochondrial dysfunction and originated tryptamine-4,5-dione, which could have further inhibited tryptophan hydroxylase. These results underscore the importance of assessing acute, low-level neurobehavioral effects of methylmercury.