OBJECTIVETo estimate the effect of aluminum on hippocampal intracellular Ca²+ concentration and expression of phospholipase C (PLC) and NMDA receptor α (NMDARα) genes in hippocampus as well as the neural behaviors in weaning rats through subchronic exposure in order to explore the mechanism which aluminum impaired the ability of learning and memory of central nervous system development.

METHODSWeaning Wistar rats were randomly divided into four groups based on their body weight. Aluminium chloride was administered by water at the doses of 0.2%, 0.4% and 0.6% (m/v) for 90 days. Platform experiment was used to detect the activity of learning and memory. Fura-2/AM calcium ions fluorescence indicator was used to measure Ca²+ concentration in hippocampal neurons. Western blot method was used to detect the expressions of PLC and NMDARα genes.

RESULTSThe incubation of rats in platform experiment [(232.20 ± 57.45), (35.00 ± 9.37), (16.10 ± 5.57) s] shortened while increase of mistake times (1.10 ± 0.74, 2.20 ± 0.92, 3.40 ± 1.51) was significantly associated with the dose of aluminum (P < 0.01). The Ca(2+) concentration decreased significantly in the rats of aluminum exposed groups (P < 0.01). The expression of PLC and NMDARα in aluminum exposed groups (0.30 ± 0.06, 0.18 ± 0.04, 0.16 ± 0.03; 0.38 ± 0.03, 0.32 ± 0.02, 0.25 ± 0.02) decreased significantly compared with that in the control group (0.47 ± 0.07, 0.48 ± 0.04) (P < 0.01) and there was a dose-effect relationship in the NMDARα expression.

CONCLUSIONSubchronic exposure of aluminium could impair the ability of learning and memory in rats during development, inhibit the expression of NMDARα and PLC and reduce Ca²+ concentration, suggesting that the disorder of Ca²+ signaling system might be one of mechanisms of aluminium damaging the ability of learning and memory.