Objective To study the effect of deltamethrin(DM) on intracellular free Ca 2+ concentration(
i)in rat
neural cells as well as the possible mechanism.Methods The i of neural cells from acute dissociated cerebral cortex and hippocamous was detected with the application of fluorescence spectrophotometry using the Ca 2+ indicator Fura 2/AM.The possible mechanism by which DM alters the i was explored by means of NMDA competitive and non competitive antagonist (AP 5 and MK 801),voltage dependent sodium channel blocker(tetrodotoxin,TTX),voltage dependent Ca 2+ channel blocker(Nimodipine,NIM),respectively.The change of i was also observed when moving out the extracellular Ca 2+ .Results DM could sharply increased i in neural cells from cerebral cortex and hippocampus when the dosage of DM from 0 nmol/L to 200nmol/L( P <0 01),and there was a positive relationship between the level of i and the DM dosage (r=0 964 and r=0 981,respestively).The action of DM increasing i coluld be completely blocked by AP 5,MK 801 and TTX,but NIM had no influence on i;It was found that DM could not increase i when moving out the extracellular Ca 2+ .Conclusion The action of DM increasing i correlated mainly with influx of extracellular Ca 2+ due to the open of ligand gated Ca 2+ channels which was activated by glutamate,not with the voltage gated Ca 2+ channels and the release from internal Ca 2+ stores.