Neurotoxicity of paraquat and triphenyltin in the earthworm, Eisenia fetida Sav. A histo- and cytopathological study.
Neuropathological effects of the pesticides paraquat (PQ, a herbicide) and triphenyltin (TPT, a fungicide) were studied on the postclitellar segmental ganglia of juvenile E. fetida specimens using light and electron microscopic methods. Growth retardation of the worms in standard culture medium was used as quantitative marker of sublethal effect. There is a distinct neuron group in the segmental ganglia characterised by high sensitivity against PQ- and another one against TPT-toxication. However the marked histo- and neurocytopathological alterations were similar in PQ and TPT treated worms. Both chromatolysis and vacuolation of perikarya were revealed in sensitive neurons. Damaged cells were swollen and possessed degenerated rough endoplasmic reticulum cisternae. They were also characterised by swollen mitochondria, with electronlucent matrix and damaged inner membranes, and vesicular structures of various diameters as well as numerous lysosomes. Necrotic neurons with pyknotic nuclei and highly eosinophilic cytoplasm were also found in affected ganglia. Several dividing neurons were found in PQ-toxicated worms while no cell division occurred either in control or TPT-toxicated animals. The exact neurochemical and functional identification of PQ- and TPT-sensitive neurons needs further investigations.
Zsombok
A
A
Department of General Zoology and Neurobiology, Janus Pannonius University, Pécs, Hungary.
Molnár
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L
Fischer
E
E
D000818:Animals; D004305:Dose-Response Relationship, Drug; D017952:Ganglia, Invertebrate / Q000187:drug effects* / Q000648:ultrastructure; D009474:Neurons / Q000473:pathology; D009835:Oligochaeta / Q000187:drug effects* / Q000254:growth & development; D009947:Organotin Compounds / Q000633:toxicity*; D010269:Paraquat / Q000633:toxicity*; D018675:Toxicity Tests
D009947:Organotin Compounds; C030665:triphenyltin; D010269:Paraquat