OSMOLALITY, METALLOTHIONEIN AND NA/KATPASE ACTIVITY IN A MANGROVE CRAB, UCIDES CORDATUS, SUBMITTED TO ACUTE AND CHRONIC COPPER EXPOSURE IN THE WATER

Abstract

Ucides cordatus were submitted to acute (24h and 96h) and chronic copper (Cu) exposure (15 days), containing 5mg/L CuSO4 in the water. Anterior and posterior gills, hepatopancreas (HP), and aliquots of haemolymph and urine were collected to measure osmolality, metallothionein (MT) concentration and Na/K‐ATPase activity (NKA). Haemolymph showed an increase in osmolality for crabs submitted to 24h Cu exposure, while animals submitted for 96h and 15 days to Cu demonstrated a reduction in osmolality compared to control. There was no change in urine osmolality for animals exposed to Cu for 24h and 15 days, while in the 96h group, there was a small reduction in the osmolality. MT synthesis increased in the anterior gills in crabs exposed to 24h, 96h and 15 days of Cu exposure, while posterior gills showed increased MT concentration in the 24h and 15 days groups, but not in the 96h group, suggesting that there is a regulation between MT concentration and time of exposure to water Cu. There was an increase of NKA in the anterior gills, while in the posterior gills there was reduction in the 24h group and an increase in the 96h and 15 days group compared to controls. For HP, there was an increase of activity for 96h group, while for the 15 days group the values were similar to control. Animals exposed to Cu show a relationship between time of exposure and higher MT concentration and increased NKA in both organs as well as alterations in osmolality.