In vitro effect of zinc and cadmium on acetylcholinesterase and ectonucleotidase activities in zebrafish (Danio rerio) brain

Zinc and cadmium are environmental contaminants that induce a wide range of effects on CNS. Here we tested the in vitro effect of these metals on acetylcholinesterase (AChE) and ectonucleotidase (NTPDase and ecto-5′-nucleotidase) activities in zebrafish brain. Both zinc and cadmium treatments did not alter significantly the zebrafish brain AChE activity. ATP hydrolysis presented a significant increase at 1 mM zinc (17%) and the AMPase activity had a dose-dependent increase at 0.5 and 1 mM zinc exposure (188% and 199%). After cadmium treatment, ATPase activity was significantly increased (53% and 48%) at 0.5 and 1 mM, respectively. Cadmium, in the range 0.25–1 mM, inhibited ADP hydrolysis in a dose-dependent manner (13.4–69%). Ecto-5′-nucleotidase activity was only inhibited (38%) in the presence of 1 mM cadmium. It is possible to suggest that changes on NTPDase and ecto-5′-nucleotidase activities can be an important mechanism involved in neurotoxic effects promoted by zinc and cadmium.