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(T/EH039) In vitro dichlorvos toxicity to cultured marine fish ( S. aurata and D. labrax) using cholinesterase activity as effect criteria. Varó, Inmaculada1, Amat, Francisco1, Navarro, Juan Carlos1, Guilhermino, Lucia2, 1 2 ABSTRACT- The in vitro toxicity of the organophosphorous (OPs) pesticide dichlorvos to two species of cultured marine fish (Sparus aurata and Dicentrarchus labrax) using cholinesterase (ChE) as effect criteria was investigated. The characterisation of the ChE using different substrates and specific inhibitors, and the normal range of activity in brain and muscle homogenates of non-exposed individuals, were previously determined for both species. In brain and muscle, acetylthiocholine is the substrate preferred in both species of fish. Eserine sulfate and BW284C51 significantly inhibited the brain enzyme activity at low concentrations ( Key words: Cholinesterase, marine fish, pesticide toxicity, biomarker |
M range), and Iso-OMPA had no significant effect. These results indicate that in the brain the predominant ChE form was acetylcholinesterase (AChE). In muscle, the three inhibitors had significant effect on the enzyme activity of S. aurata, whereas in D. labrax muscle, eserine and BW284C51 inhibited the enzyme activity. No effect was observed with Iso-OMPA. These findings suggest that in the muscle of S.aurata both butyrylcholinesterase (BChE) and AChE are present. In contrast, ChE activity comprised AChE in D. labrax muscle. The values of normal ChE activity in brain and muscle were 47.78 ± 1.02 and 24.61 ±0.66 U/mg protein respectively for S. aurata, and 52.68 ±1.37 and 16.43 ± 0.9 U/mg protein for D. labrax. Dichlorvos inhibited the activity of ChE in vitro from brain and muscle.