Neurotoxic potential of six organophosphorus compounds in adult hens
Abdelsalam, E.B.
Veterinary and Human Toxicology 41(5): 290-292
1999
ISSN/ISBN: 0145-6296 PMID: 10509429 Document Number: 510008
The neurotoxic potentials of trichlorfon, diazinon, phosmet, dichlorvos, phosphamidon, coumaphos and leptophos were evaluated for their ability to inhibit brain neurotoxic esterase (NTE) activity in adult hens. Eight equal groups of 6 adult hens were used in the experiment. Leptophos was used as a reference neurotoxic agent. All compounds were administered at high single oral doses and the NTE and acetylcholinesterase (AchE) activities were measured at 24 h and 6 weeks later. With the exception of leptophos, all compounds produced severe cholinergic signs associated with >80% inhibition of brain AchE at 24 h. On the other hand, brain NTE activity was 86% inhibited by leptophos and to lesser extents by trichlorfon (76%), phosphamidon (74%), coumaphos (70%) and dichlorvos (70%). However, none of the latter compounds produced clinical delayed neurotoxicity as was observed with leptophos. It is concluded that trichlorfon, phosphamidon, coumaphos and dichlorvos are potentially neurotoxic because of their ability to inhibit brain NTE activity, but the extent of inhibition required for development of clinical delayed neurotoxicity (>80%) is not likely to occur with any of these compounds due to their severe cholinergic activity.