The acute and subchronic effects of organophosphorus and carbamate pesticides on cholinesterase activity in aggregate cultures of neural cells from the foetal rat brain.
The biochemical and morphological effects of five organophosphorus and carbamate pesticides were examined in aggregate cultures of neural cells from rat brains. Acute cholinesterase inhibition assays with carbofuran were performed on culture days 5, 10 and 17. No significant age-related differences in the median inhibitory concentrations (IC(50)s) were detected. When the cholinesterase IC(50) values for malaoxon, fenitrothion, carbaryl and carbofuran, determined on culture day 17, were plotted against the previously published median lethal dose (oral LD(50)s) of the same compounds in rats and mice, there was a good linear relationship between IC(50) and LD(50) values. In a 14-day subchronic study with fenitrothion, total protein levels in the cultures were significantly lower than control values at all doses tested (4, 8 and 20 mug/ml medium) while cholinesterase activity was unaffected at all but the highest dose. Central necrosis was observed at the intermediate dose, while cultures exposed to the highest dose exhibited extensive cell death and abnormal cell arrangement within the aggregate.
Segal
L M
LM
Graduate Toxicology Program, University of Saskatchewan, Saskatoon, S7N 0W0 Canada.
Fedoroff
S
S