title: Effects of acute exposure to exogenous ammonia on cerebral monoaminergic neurotransmitters in juvenile Solea senegalensis.
abstract: The present study explored the potential role of brain catecholaminergic and serotoninergic systems as neuronal targets for the toxicological effects of acute ammonia exposure (0.28 mg l(-1) of un-ionized ammonia for 12 and 24 h) in juvenile sole (Solea senegalensis). In addition, plasma cortisol levels were measured. The results showed significant increases in their concentrations that were similar after 12 and 24 h of exposure. These data indicate that acute exposure (12 and 24 h) to ammonia initiates a typical stress response in the Senegalese sole, with stimulation of the hypothalamus-pituitary-interrenal axis. The concentrations of dopamine (DA), serotonin (5-hydroxytryptamine; 5-HT) and noradrenaline (NA), and their metabolites, 3, 4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxy-3-indoleacetic acid (5HIAA), were measured in the hypothalamus, telencephalon and optic tectum. The main changes induced by acute exposure to ammonia were decreases in the concentrations of 5-HT and DA, which were significant in most of the brain regions studied. The ratios of 5-HIAA/5-HT and DOPAC/DA increased in all regions and at all times studied, although in the case of the DOPAC/DA ratio, the increases were only significant in the hypothalamus (24 h exposure) and in the optic tectum (12 and 24 h exposure). These changes indicated that exposure to ammonia elicited time-dependent increases in serotoninergic and dopaminergic activity in the hypothalamus, telencephalon and optic tectum.
authors.affiliation: Departamento de Fisiología, Facultad de Biología, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: R A
authors.initials: RA
authors.lastname: Weber
authors.forename: J J Pérez
authors.initials: JJ
authors.lastname: Maceira
authors.forename: M J
authors.initials: MJ
authors.lastname: Mancebo
authors.forename: J B
authors.initials: JB
authors.lastname: Peleteiro
authors.forename: L O García
authors.initials: LO
authors.lastname: Martín
authors.forename: M
authors.initials: M
authors.lastname: Aldegunde
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000641:Ammonia / Q000633:toxicity*; D000643:Ammonium Chloride / Q000633:toxicity; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D001923:Brain Chemistry; D004298:Dopamine / Q000378:metabolism; D005412:Flatfishes / Q000502:physiology*; D006854:Hydrocortisone / Q000097:blood; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008018:Life Cycle Stages / Q000187:drug effects / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D015306:Biogenic Monoamines; D018377:Neurotransmitter Agents; D014874:Water Pollutants, Chemical; D000643:Ammonium Chloride; D015102:3,4-Dihydroxyphenylacetic Acid; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D000641:Ammonia; D004298:Dopamine; D006854:Hydrocortisone; D009638:Norepinephrine