OBJECTIVETo explore effect of curcumin in different concentrations on learning and memory of senescence-accelerated mice (SAM) and their possible mechanisms.

METHODSMice were randomly divided into six groups: the SAMR1 normal control group, the SAMP8 model control group, the SAMP8 + solvent (the peanut oil) control group, SAMP8 + low, middle and high dose curcumin groups. Mice were gastrogavage for 25 successive days. On the next day of ending the experiment, changes of learning and memory in mice of each group were observed by Morris water maze. The hippocampal [Ca2+] was determined. Expressions of hippocampal calmodulin-dependent protein kinase II (CaMK II) and Calmodulin (CaM) mRNA were detected using Western blot and reverse transcription polymerase chain reaction (RT-PCR) respectively.

RESULTSThe latency to find the hidden platform was remarkably prolonged, the hippocampal [Ca2+]i was markedly increased, the expression of CaMK II in the hippocampal membrane and the level of hippocampal CaM mRNA were significantly reduced in the SAMP8-model control group (P < 0.05, P < 0.01). The latency to find the hidden platform was remarkably shortened in the SAMP8 + middle dose curcumin and the SAMP8 + high dose curcumin groups (P < 0.01). The hippocampal [Ca2+]i was markedly lowered, the expression of CaMK II in the hippocampal membrane and the level of hippocampal CaM mRNA obviously increased in the SAMP8 + low, middle and high dose curcumin groups (P < 0.05, P < 0.01).

CONCLUSIONCurcumin could improve learning and memory Ca2+/capacities of SAM by lowering hippocampal [Ca2+] overload, increase the hippocampal CaM mRNA level and CaMK II expression in the hippocampal dose-dependently.