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(T/EH041) In vitro and in vivo inhibition of AChE in muscle and eye of white shrimp. García-de la Parra, Luz-Maria1, Bautista-Covarrubias, Juan-Carlos1, Betamcourt-Lozano, Miguel1, Guilhermino, Lucia2, 1 2 ABSTRACT- . It has been demonstrated that organophosphate pesticides can inhibit the activity of cholinesterases (ChEs) in many organisms. Nevertheless, before using this enzyme as environmental biomarker, the ChE forms present in species and in tissue to be used should be performed. In this study, the characterisation of ChEs present in muscle and in eye of the white shrimp (Litopenaeus vannamei) was performed using three different substrates (acetyltiocholine, propionyltiocholine and butiryltiocholine) and three selective inhibitors (eserine sulphate, iso-OMPA and 1,5-bis (4-allyldimethylammoniumphenyl)-pentan-3-one (BW284c51)). Furthermore, the effects of an organophosphate insecticide on L. vannamei ChE activity of muscle and eye were determined both in vitro and in vivo conditions. The rate of substrate hydrolysis of L. vannamei muscle was slower in muscle than in eye for all the substrates. Eserine sulphate and BW284c51 significantly inhibited the enzyme activity at concentrations in the 0.006-0.100 mM range both for muscle and eye. By the contrast, iso-OMPA had no significant effect at concentrations of 1 to 32 mM. The enzyme activity determined in organisms exposed to different concentrations of metamidophos both in vitro and in vivo were dose-dependent in both tissues. Key words: Ecotoxicology, white shrimp, acetylcholinesterase, pesticides |
