Importance of cholinesterase kinetic parameters in environmental monitoring using estuarine fish

• Published in: Chemosphere (Oxford) 2006-10, Vol.65 (4), p.560-566
• Main Authors: Tortelli, V., Colares, E.P., Robaldo, R.B., Nery, L.E.M., Pinho, G.L.L., Bianchini, A., Monserrat, J.M.
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Animals; Applied ecology; Ariidae; Biological and medical sciences; Biomarkers; Biomarkers - metabolism; Brackish; Brain - drug effects; Brain - enzymology; Brazil; Catfishes - growth & development; Cathorops spixii; Cholinesterase; Cholinesterase Inhibitors - toxicity; Cholinesterases - metabolism; Ecotoxicology, biological effects of pollution; Environmental Monitoring - methods; Eserine; Estuaries; Fish; Fishes - growth & development; Fundamental and applied biological sciences. Psychology; General aspects; Kinetic parameters; Kinetics; Micropogonias furnieri; Perciformes - growth & development; Teleostei; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Water Pollutants, Chemical - toxicity
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2006.02.047

The aim of the present study was to determine the kinetic parameters and cholinesterase (ChE) activity in two teleost fish, the white mouth croaker Micropogonias furnieri (Scianidae) and the Madamango sea catfish Cathorops spixii (Ariidae), to verify their suitability as sentinel species of aquatic pollution by anticholinergic compounds. Individuals of each species were captured in one reference and one polluted site in the Southern Brazilian coast. Brain tissue was used as enzyme source. Inhibition kinetic parameters indicated that ChE from C. spixii collected at the reference site showed more affinity ( K a) for eserine that from those collected at the polluted site. The opposite was observed for the carbamylation constants ( K c). Thus, similar inhibition constants ( K i) were observed. M. furnieri brain showed an extremely low sensitivity to in vitro inhibition by eserine, indicating that it is not a suitable biomarker to be employed in environmental monitoring of anticholinergic compounds. Results from the present study also point to the need for considering kinetic analysis when cholinesterase activity is employed as a biomarker.