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Effects of mercury intoxication on the response of horizontal cells of the retina of thraira fish (Hoplias malabaricus)

Texto completo
Autor(es):
C.L. Tanan ; D.F. Ventura ; J.M. de Souza ; S.R. Grotzner ; M. Mela ; A. Gouveia Jr. ; C.A. Oliveira-Ribeiro
Número total de Autores: 7
Tipo de documento: Artigo Científico
Fonte: Brazilian Journal of Medical and Biological Research; v. 39, n. 7, p. 987-995, Jul. 2006.
Resumo

Methyl mercury (MeHg) is highly neurotoxic, affecting visual function in addition to other central nervous system functions. The effect of mercury intoxication on the amplitude of horizontal cell responses to light was studied in the retina of the fish Hoplias malabaricus. Intracellular responses were recorded from horizontal cells of fish previously intoxicated with MeHg by intraperitoneal injection (IP group) or by trophic exposure (T group). Only one retina per fish was used. The doses of MeHg chloride administered to the IP group were 0.01, 0.05, 0.1, 1.0, 2.0, and 6.0 mg/kg. The amplitudes of the horizontal cell responses were lower than control in individuals exposed to 0.01 (N = 4 retinas), 0.05 (N = 2 retinas) and 0.1 mg/kg (N = 1 retina), whereas no responses were recorded in the 1.0, 2.0, and 6.0 mg/kg groups. T group individuals were fed young specimens of Astyanax sp previously injected with MeHg corresponding to 0.75 (N = 1 retina), 0.075 (N = 8 retinas) or 0.0075 (N = 4 retinas) mg/kg fish body weight. After 14 doses, one every 5 days, the amplitude of the horizontal cell response was higher than control in individuals exposed to 0.075 and 0.0075 mg/kg, and lower in individuals exposed to 0.75 mg/kg. We conclude that intoxication with MeHg affects the electrophysiological response of the horizontal cells in the retina, either reducing or increasing its amplitude compared to control, and that these effects are related to the dose and/or to the mode of administration. (AU)

Processo FAPESP: 02/12733-8 - Perdas sensoriais causadas pela intoxicação mercurial: estudos psicofísicos e neurofisiológicos em pacientes e em modelos animais
Beneficiário:Dora Selma Fix Ventura
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 03/02700-8 - Estudo eletrofisiológico dos efeitos de intoxicação mercurial em retina de peixe
Beneficiário:Christiane Lopes Tanan
Linha de fomento: Bolsas no Brasil - Mestrado