Effect of copper and cadmium ions on heart function and calpain activity in blue musselMytilus edulis

Abstract The heart rate and calpain activity of blue mussels Mytilus edulis from the sublittoral zone, exposed to different levels of water-borne copper and cadmium, was investigated in a long-term experiment. The content of cadmium and copper in the blue mussel was determined using flame and graphite Atomic absorption spectroscopy. The observed concentrations ranged from 2.5 to 89.1 μg/g dry weight for cadmium and from 6.1 to 51.0 μg/g dry weight for copper in the control and highest concentration, respectively. Initially, increase in cardiac activity in response to copper and Cadmium exposure was observed under all pollutant concentrations (5–250 and 10–500 μg/L, respectively). The calpain-like activity in gills and hepatopancreas of the mussels treated with metals changed in dose- and time-dependent manner: from a sharp rise at the 250 μg/L concentration of copper on the first day to a significant decrease under the effect of Cadmium in the concentration of 500 μg/L on the third day of the experiment. These results suggest that: (i) heart rate oscillation may reflect active adaptation of blue mussels to contamination and (ii) animals have different sensitivity to copper and Cadmium according to the role of the metals in the mussels' life activity. Keywords: Blue musselcadmiumcalpaincopperheart rateheavy metals Mytilus edulis L Acknowledgments We wish to extend our warm thanks to the deputy director of the Institute of North Industrial Ecology Problems Kola Science Center RAS Kashulin N.A. and employee of the same institute. We are also deeply grateful to the staff of the White Sea Biological Station, Zoological Institute of RAS and especially Drs. V.J. Berger and V.V. Khalaman for the assistance in the maintenance of the animals. The work was supported by grant from Russian Foundation for Basic Research 11–04-00167; the President RF grant "Leading Scientific Schools" 3731.2010.4; the project of Ministry of Education & Science RF (contract No 14.740.11.1034), and the project of the RAS Council for Biological Sciences program "Basics of biological resource management."