In vitro assessment of the effects of cadmium and zinc on mammalian nerve fibres

Zinc and cadmium are environmental contaminants that have a wide range of effects on the nervous system, but zinc is also considered to be an important metal in the human body. In this study the effect of CdCl2 and ZnCl2, at concentrations of 50,150, 250 and 500 μM, on the nerve fibres of the sciatic nerve of the rat isolated in a three-chamber recording bath were studied. At the same concentrations, CdCl2 and ZnCl2 were found to have almost the same inhibitory effect on the compound action potential (CAP) of the nerve fibres. Their concentration–effect curves almost overlap and there was no significant difference in their EC50 which for CdCl2 is 250.1 ± 18 μM (n = 5) and for ZnCl2 is 282.2 ± 25 μM (n = 5) correspondingly (P > 0.05). The no-observed-effect concentration (NOEC) was estimated to be 50–100 μM for both metals. The identical inhibitory effect of both metals on the sciatic nerve fibres indicates a common mode of action which is related to their potential to generate reactive oxygen species (ROS).