title: Insights into neurosensory toxicity of mercury in fish eyes stemming from tissue burdens, oxidative stress and synaptic transmission profiles.
abstract: This study aims to contribute to fill a knowledge gap related with Hg effects in fish eyes. As a pioneering strategy, Hg bioaccumulation in eye wall of the wild grey mullet (Liza aurata) was assessed, together with oxidative stress and synaptic transmission profiles. This approach was complemented by the characterisation of environmental contamination (both in water and sediment). Sampling was conducted in winter and summer in two sites of a Portuguese coastal lagoon (Aveiro lagoon): Largo do Laranjo (LAR) - located in an Hg contaminated/confined area; São Jacinto (SJ) - closer to the lagoon inlet and selected as reference site. Levels of total Hg (tHg), inorganic Hg (iHg) and methylmercury (MeHg) in eye wall were higher at LAR than SJ, both in winter and summer, reflecting the environmental contamination patterns. Moreover, fish caught at LAR in winter showed a significant decrease of catalase and superoxide dismutase activities, in line with the occurrence of peroxidative damage. A different spatial pattern was recorded in summer, being characterised by the increment of glutathione peroxidase and glutathione reductase activities at LAR, as well as total glutathione content, preventing the occurrence of lipid peroxidation. Also in summer, a significant decrease of acetylcholinesterase activity was recorded in fish eyes at LAR, pointed out Hg as an anticholinergic agent. Besides Hg, water salinity had probably an indirect effect on spatial and winter-summer variation patterns of AChE. Current data pointed out that Hg (in iHg and MeHg forms) could exert ocular toxicity both by the promotion of oxidative stress and by the interference with neurotransmission processes.
authors.affiliation: Biology Department and CESAM, Aveiro University, 3810-193 Aveiro, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Pereira
authors.affiliation: Biology Department and CESAM, Aveiro University, 3810-193 Aveiro, Portugal.
authors.forename: Sofia
authors.initials: S
authors.lastname: Guilherme
authors.affiliation: Biology Department and CESAM, Aveiro University, 3810-193 Aveiro, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Brandão
authors.affiliation: IPMA - Portuguese Institute for the Sea and Atmosphere, Av. Brasília, 1449-006 Lisbon, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Raimundo
authors.affiliation: Biology Department and CESAM, Aveiro University, 3810-193 Aveiro, Portugal.
authors.forename: Maria Ana
authors.initials: MA
authors.lastname: Santos
authors.affiliation: Biology Department and CESAM, Aveiro University, 3810-193 Aveiro, Portugal.
authors.forename: Mário
authors.initials: M
authors.lastname: Pacheco
authors.affiliation: Biology Department and CESAM, Aveiro University, 3810-193 Aveiro, Portugal; IPMA - Portuguese Institute for the Sea and Atmosphere, Av. Brasília, 1449-006 Lisbon, Portugal. Electronic address: pkpereira@ua.pt.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Pereira
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D005123:Eye / Q000737:chemistry; D005128:Eye Diseases / Q000139:chemically induced / Q000662:veterinary*; D005393:Fish Diseases / Q000139:chemically induced*; D005399:Fishes; D019015:Geologic Sediments / Q000737:chemistry; D008628:Mercury / Q000633:toxicity*; D012623:Seawater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Fish eyes; Mercury; Neurotransmission; Ocular toxicity; Oxidative stress