NEUROPATHOLOGY INDUCED BY TRIMETHYLTIN IN THE CENTRAL-NERVOUS-SYSTEM OF THE URODELE TRITURUS-CARNIFEX

The effects of trimethyltin (TMT) exposure on the amphibian central nervous system (CNS) were investigated. Larvae of Triturus carnifex were maintained for two days in water containing three different concentrations (0.75, 1.5, 3 mg/l) of TMT. In addition, two groups of adult males of the same species received (ip) 3 and 12 mg TMT/kg b.w., respectively. All the larvae tested with 3 mg TMT/l died. Neuropathological damages in the telencephalon, diencephalon and mesencephalon were seen in the surviving animals. Larvae tested with 1.5 mg TMT/l presented several pyknotic neurons with different density relatively to the areas considered. A similar, though less pronounced effect was observed in larvae tested with 0.75 mg TMT/l. The adult newts treated with 12 mg TMT/kg b.w. presented a very high density of shrunken neurons but very few pyknotic cells. The adult newts treated with 3 mg TMT/kg b.w. were not apparently affected. The comparison between TMT neuropathological effects in adult T. carnifex and those obtained in previous investigations in mammalian species reveals that the doses necessary to produce neuronal damages in the CNS are similar in T. carnifex and in rat. Nevertheless, the neuropathological pattern observed in T. carnifex is more diffuse and less severe if compared with that described in mammals in which the hippocampus is preferentially and extensively affected.