title: [Effects of organophosphates on cell proliferation and 45Ca uptake of neuroblastoma SH-SY5Y cells].
abstract: OBJECTIVE
  To explore the mechanism of cytotoxic effects of the organophosphates (OPs) with delayed neurotoxicity on human neuroblastoma cells.
  
  
  METHODS
  The proliferation of neuroblastoma SH-SY5Y cells was determined by MTT spectrometry. (45)Ca uptake was determined by adding (45)CaCl(2) and tri-o-cresyl phosphate (TOCP) or methamidophos into the cultured medium for the SH-SY5Y cells. The cells were incubated and then lysed and finally counted in a Beckman LS 6000 liquid scintillation spectrometer.
  
  
  RESULTS
  Methamidophos stimulated the cell proliferation of SH-SY5Y at its lower concentrations (7 x 10(-7) mol/L to 7 x 10(-6) mol/L), with an increase by 28% at 7 x 10(-7) mol/L; however, it inhibited the proliferation at higher ones (7 x 10(-4) mol/L to 7 x 10(-3) mol/L) with 62% inhibition at 7 x 10(-3) mol/L. TOCP only inhibited the cell proliferation at high concentration (with 34% inhibition at 7 x 10(-3) mol/L) and markedly inhibited calcium uptake of the cells up to 55% at higher concentrations (1 x 10(-6) mol/L to 1 x 10(-4) mol/L); while the uptake was stimulated by OPs up to 241% of increase at lower concentrations (1 x 10(-9) mol/L to 1 x 10(-7) mol/L).
  
  
  CONCLUSIONS
  The interference of growth in nerve cells and disturbance of calcium homeostasis may be involved in the mechanisms of neurotoxicity of OPs.
authors.affiliation: Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Ping-an
authors.initials: PA
authors.lastname: Chang
authors.forename: Yu-xia
authors.initials: YX
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Yi-jun
authors.initials: YJ
authors.lastname: Wu
mesh_terms: D002132:Calcium Radioisotopes / Q000378:metabolism* / Q000493:pharmacokinetics; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects; D006801:Humans; D007306:Insecticides / Q000008:administration & dosage*; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology; D009943:Organophosphorus Compounds
chemical_list: D002132:Calcium Radioisotopes; D007306:Insecticides; D009943:Organophosphorus Compounds