Recovery of neuropathy target esterase activity after inhibition with mipafox and O-hexyl O-2,5-dichlorophenyl phosphoramidate in bovine chromaffin cell cultures.
Neuropathy target esterase (NTE) is a membrane protein present in various tissues whose physiological function has been recently suggested to be the maintenance of phosphatidylcholine homeostasis. Inhibition and further modification of NTE by certain organophosphorus compounds (OPs) were related to the induction of the "organophosphorus induced delayed neuropathy". Bovine chromaffin cells were cultured at 75,000cells/well in 96-well plates and exposed to 25microM mipafox or 3microM O-hexyl O-2,5-dichlorophenyl phosphoramidate (HDCP) for 60min. Inhibitors were removed by washing cells three times with Krebs solution. Then NTE activity was assayed at 0, 24, 48 and 120h after exposure using the Biomek 1000 workstation. Immediately after mipafox treatment NTE activity represented 3% of the control (6.7+/-1.9mU/10(6) cells). At 24, 48 and 120h after removing inhibitor, recorded activities were 33%, 42% and 111% of their respective controls (5.7+/-3.1; 5.7+/-1.9; 5.4+/-0.0mU/10(6) cells, respectively). Treatment with HDCP also displayed a time-dependent pattern of NTE recovery. As NTE inhibited by phosphoramidates is not reactivated in homogenized tissues, these results confirm a time-dependent regeneration of NTE after inhibition by neuropathic OPs.
Quesada
Encarna
E
Unidad de Toxicología y Seguridad Química, Instituto de Bioingeniería, Universidad Miguel Hernández, Avda. de la Universidad, s/n E-03202 Elche (Alicante), Spain. equesada@umh.es
Sabater
Esther
E
Sogorb
Miguel Angel
MA
Vilanova
Eugenio
E
Carrera
Victoria
V
D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000187:drug effects* / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007531:Isoflurophate / Q000031:analogs & derivatives* / Q000494:pharmacology; D020258:Neurotoxicity Syndromes / Q000201:enzymology; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D020127:Recovery of Function; D013997:Time Factors
D004791:Enzyme Inhibitors; D009943:Organophosphorus Compounds; C066606:hexyl 2,5-dichlorophenylphosphoroamidate; D007531:Isoflurophate; C005238:mipafox; D002265:Carboxylic Ester Hydrolases; C021859:neurotoxic esterase