Effect of acute morphine on memory and τ phosphorylation of the prefrontal cortex of rats

Objective To explore the effect of acute morphine on memory and τ phosphorylation of the prefrontal cortex of rats.Methods Forty SD rats were randomly divided into two groups with 20 rats each.Group M received intraperitoneally injection of morphine 30 mg/kg.Group C was given normal saline instead of morphine as the control.Ten rats from each group were sacrificed to get the prefrontal cortex for detecting τ protein phosphorylation at the sites Ser396 and Thr231 with immunoblotting at 2 h and 24 h after injections.Laterly sacrificed rats in each group were tested with morris water maze(MWM) at 2 h,4 h and 24 h after injections.Results The latent period was significantly longer in group M than that of group C(P0.01) at 2 h after injections.The hyperphosphorylation at the sites of Ser396 and Thr231 of τ in group M was significantly higher than that in group C(P0.05) at 2 h after injection.Conclusion The intraperitoneally injection of morphine 30 mg/ kg may lead to transient memory decrease in rats,which may be related to the hyperphosphorylation at the sites of Ser396 and Thr231of τ in the prefrontal cortex.