The toxicity and neuropathology of dimethylethyltin and methyldiethyltin in rats.

Triethyltin causes an increase in brain water with vacuolation of myelin sheaths, whereas trimethyltin is selectively damaging to neurons, especially of the hippocampal formations, causing chromatolysis, accumulation of cytoplasmic dense bodies and often cell death. The effects on rats of the analogues, dimethylethyltin and methyldiethyltin (oral LD50 14 mg/kg and 7.5-10.0 mg/kg respectively) are now reported. The dimethylethyl compound produces functional changes resembling those caused by trimethyltin, while the methyldiethyl compound causes responses similar to those produced by triethyltin. Structurally, however, the dimethylethyl compound, while producing marked nerve cell changes of the trimethyltin type also causes moderate vacuolation of myelin sheaths. By contrast, methyldiethyltin causes marked vacuolation of myelin sheaths of the triethyltin type and relatively minor neuronal changes of the trimethyltin type. These findings are discussed in terms of the structure-activity relationships of trialkyltin compounds.