ATENOLOL INDUCES CHANGES IN THE SWIMMING BEHAVIOR AND ACETYL CHOLINESTERASE ACTIVITY OF Jenynsia multidentata FISH

VALDÉS, MARÍA EUGENIA; WUNDERLIN, DANIEL A.; BISTONI MA. DE LOS ANGELES

Guarapari

Congreso; ECOTOX 2014 XIII Congresso Brasileiro de Ecotoxicologia; 2014

Sociedade Brasileira de Ecotoxicologia y SETAC

IntroduçãoPharmaceuticals are a class of emerging environmental contaminants found in several watercoursesworldwide, particularly those receiving inputs from wastewater treatment plants (WWTP). In the Suquía River(Córdoba, Argentina) atenolol, a β-blocker used to treat heart diseases, was frequently found up to μgL-1levels, downstream from the WWTP of Córdoba city (Valdés et al., 2014). Yet, atenolol effects on the biota arescarcely known. The objective of this work was to evaluate effects of atenolol on the swimming behavior of J.multidentata, a fish inhabiting Suquía river, as well as changes in the activity of acetyl cholinesterase (AchE),an enzymatic biomarker commonly associated with locomotion.MetodologiaFemale adults of J.multidentata (0.5±0.2 g weight ; 29±2 mm standard longitude) were collected in a quasipristinearea (Río Yuspe, Córdoba, Argentina), adapted to laboratory conditions at 21±1 ºC, 12:12 h light:darkphotoperiod and fed once a day with commercial fish pellets. Fish were exposed 14 days to 0, 1 and 50 μgL-1of atenolol in dechlorinated water (1L/fish; n=10 for behavioral tests; n=5 for enzymatic assays). Aquariumsolutions were renewed every 48h and samples were taken for analysis of atenolol concentration in waterbefore and after renewal. At the end of the exposure, fish were transferred individually to aquariums specificallydesigned for recording the swimming activity with a digital camera. Fish were familiarized with the aquariumduring 2 min and their movements recorded for 10 min. Swimming behavior was evaluated measuring the totaldistance traveled along recorded time. The software package used was Any-Maze 4.96. After recording, fishwere anesthetized and dissected. Fish brain, muscle and liver were shock-frozen in liquid nitrogen and kept at -80ºC until enzymatic extraction as reported by Cazenaveet al., (2006). AchE activity was measured inaccording to Ellmanet al., (1961) on protein weight basis (Bradford, 1976). LinearMixed Models (SPSSStatistics 17.0) were applied for statistical analysis.Resultados e DiscussãoThe measured concentrations of atenolol in aquarium water were: below limit of detection (LOD= 0.2ngL-1) forthe control group; 0.9±0.1 μgL-1 and 62±2μgL-1 at starting time; 0.8±0.1 μgL-1 and 64±1 μgL-1 after 48hexposure.AchE activity was significantly inhibited in all organs analyzed with respect to the control group. Brain was theorgan with most pronounced inhibition percentage at both levels of atenolol used during the experiment. AchEin muscle was inhibited at the higher concentration. These results could mean that acetylcholine in exposedfish is not degraded as fast as it is in the control group; as a result, nerve impulses keep the transmission forlonger periods. Results from swimming behavior showed that total distance traveled was significantly higher intreated groups compared to controls. This alteration could derive in fish spending more energy in locomotionthan they normally would, which in turn could represent a threat to them, since they could probably be moreexposed to predators.ConclusãoAlterations in cholinergic neurotransmission and locomotion of J. multidentata females, exposed toenvironmentally relevant concentrations of atenolol during 14 days, present the first evidence of changes in fishexposed to environmental relevant levels of atenolol, raising questions on other probable alterations that couldadd ecological risk to this and other species inhabiting the polluted basin. The simultaneous presence ofcomplex mixture of pharmaceuticals and other contaminants poses an additional risk that needs to beevaluated in future works.