DAO 55:237-245 (2003)  -  doi:10.3354/dao055237

Increased recovery of brain acetylcholinesterase activity in dichlorvos-intoxicated European eels Anguilla anguilla by bath treatment with N-acetylcysteine

Samuel Peña-Llopis1,*, Dolores Ferrando2, Juan B. Peña1

1Institute of Aquaculture Torre de la Sal (CSIC), 12595 Ribera de Cabanes (Castellón), Spain
2Department of Animal Biology (Animal Physiology), Faculty of Biology, University of Valencia, Dr. Moliner-50, 46100 Burjassot (Valencia), Spain

ABSTRACT: Organophosphate (OP) pesticides are widely used as antiparasitic chemicals in finfish aquaculture. However, current antidotes cannot be applied to treat intoxicated fish. We showed in previous studies the importance of glutathione (GSH) metabolism in pesticide resistance of the European eel Anguilla anguilla L. The present work studied the effects of the antioxidant and glutathione pro-drug N-acetyl-l-cysteine (NAC) on the recovery of European eels exposed for 96 h to a sublethal concentration (0.17 mg l-1; 20% of its 96 h LC50) of the OP pesticide dichlorvos (2,2-dichlorovinyl dimethyl phosphate; DDVP). This insecticide and acaricide decreased muscular GSH content and increased oxidised glutathione (GSSG), lowering the GSH:GSSG ratio, which is indicative of a condition of oxidative stress. Acetylcholinesterase (AChE) and glutathione reductase (GR) activities in the brain, which were biomarkers of neurotoxicity and oxidative stress, respectively, were also highly inhibited. Recovery in a 0.5 mM (81.6 mg l-1) NAC concentration ameliorated muscular GSH depletion, GSH:GSSG ratio, and the inhibition of brain AChE and GR activities. Hence, this is the first evidence of improved recovery of organophosphate-poisoned fish by bath treatments.

KEY WORDS: Detoxification · Organophosphorus pesticide · Organophosphate poisoning · Cholinesterase inhibitor · Oxidative stress · N-acetyl-l-cysteine · AChE · Glutathione metabolism

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