EVALUATION OF THE TOXICITY OF DIFFERENT METAL-COMPOUNDS IN THE DEVELOPING BRAIN USING AGGREGATING CELL-CULTURES AS A MODEL

To evaluate their toxicity in the developing brain, eight metal compou nds, [bismuth sodium tartrate (BiNA-tartrate), CdCl2, CoCl2, HgCl2, di methyl mercury, NiCl2, TlCl and triethyltin chloride (TET)] were teste d in aggregating cell cultures of foetal rat telencephalon. The compou nds were applied to the cultures continuously, either during an early developmental stage (between days 5 and 14) or during and advanced sta ge of maturation (between days 24 and 34). Changes in the activities o f cell type-specific enzymes were used as a criterion for toxicity. A general cytotoxic effect was observed after treatment with either CdCl 2, HgCl2 or TET at 10(-6) m, and with TlCl at 10(-5) m. Selective effe cts were found with BiNa-tartrate and dimethylmercury. CoCl2 did not m odify the parameters tested, whereas a stimulant effect was found with NiCl2. The effects of several compounds were development dependent: H gCl2, TET and TlCl were more toxic in immature cultures, whereas BiNa- tartrate, dimethylmercury and NiCl2 were more effective in differentia ted cultures.