Modification of mipafox-induced inhibition of neuropathy target esterase in neuroblastoma cells of human origin.

A neuroblastoma cell line of human origin was used as an in vitro model system to examine early effects on inhibition of neuropathy target esterase (NTE, also known as neurotoxic esterase) in the presence of agents belonging to classes of chemicals previously demonstrated to modify organophosphorus-induced delayed neuropathy in hens. For this study, differentiated SY-5Y cells were treated for up to 10 min with mipafox, an organophosphorus compound, and NTE inhibition was determined when cells exposed to mipafox were also exposed to the carbamate, aldicarb, and to the calcium channel blocker, verapamil. Cells were exposed to aldicarb or verapamil 5 min before, at the same time, or 2 min after mipafox. Less NTE inhibition was observed when either aldicarb or verapamil was included in the incubation of SY-5Y cells with mipafox. Effects of aldicarb and verapamil on NTE inhibition in differentiated SY-5Y cells were similar to effects in chicken brain homogenates. These results indicate that NTE inhibition can be detected in neuroblastoma cells, that these cells respond in a manner similar to chicken brain, and that mipafox-induced inhibition of NTE can be decreased in the presence of aldicarb or verapamil.