OBJECTIVETo investigate the neuroprotective effect of estradiol on the release of excitatory amino acid (EAAs) mediator, and the activity of ATPase in cerebro-cortical synaptosome membrane of rats exposed to deltamethrin.

METHODSUsing HPLC to detect EAAs release, and colorimeter method to measure the activities of Na(+)-K(+)-ATPase, Mg(2+)-ATPase, Ca(2+)-ATPase, Ca(2+)-Mg(2+)-ATPase in the cerebro-cortical synaptosomes of ovariectomized rats exposed to deltamethrin (2 x 10(-5)mol/L), and treated with different doses of 17beta estradiol (10(-5), 10(-8), 10(-11) mol/L). Meanwhile, the estrogen receptor (ER) antagonist, tamoxifen, was used to investigate the effect on estradiol.

RESULTSThe release of Asp and Glu from the cerebro-cortical synaptosomes was significantly increased by 2 x 10(-5)mol/L deltamethrin exposure at the depolarizing state evoked by 50 mmol/L KCl, while 10(-8), 10(-11) mol/L 17beta estradiol could partly inhibit the effect of deltamethrin on the release of Asp (28.42%, 24.36%, respectively), Glu (21.52%, 14.57%, respectively). The activities of 4 kinds of ATPase were inhibited by 2 x 10(-4) mol/L deltamethrin, and these effects could be blocked by 10(-5) mol/L estradiol, while the activity of Ca(2+)-ATPase was increased by 10(-8), 10(-11) mol/L of estradiol. However, no obvious antagonistic effect of tamoxifen on the function of estradial on EAAs release or the activities of ATPase was found.

CONCLUSIONEstradiol showed certain neuroprotective effect on the release of EAAs and the inhibition on ATPase induced by deltamethrin. The effect of estradiol on synaptosomes may indicate the nongenetic mechanism of estradiol.