Influence on the cellular organization in central nervous system micromass cultures

The effects of lead on cellular neuronal development and organization have been studied. Rat embryo midbrain micromass cultures were exposed to lead acetate (0.1—5.0 ag/ml) for five days. Differentiation was indicated by the formation of neuronal foci in the cultures. Effects on cell growth and survival were estimated using a neutral red staining method. Lead was found to inhibit foci formation at concentrations (0.25 and 0.5 pg/ml) which did not affect cell survival. This selective effect on neuronal development was not found for three other heavy metal compounds: trimethyltin chloride, cadmium chloride and mercury chloride. In chicken embryo midbrain micromass cultures, foei formation was inhibited by even lower concentrations of lead (0.05-0.5 ug/ml), whereas neuronal cell aggregation in cell line micromass eocultures was unaffected by lead in concentrations up to 5.0 pg/ml. It is concluded that lead causes a disturbance in the neuronal developmentin embryonic central nervous system micromass cultures by a specific and selective effect on a property only expressed in embryonic cells