[Effects of lithium on rat hippocampus cholecystokinin protein expression and learning and memory]

To investigate the effects of lithium on brain development, leaning and memory, we observed the effects of lithium chloride on rat body weight, learning ability and memory capacity.

Wistar rats were randomly divided into control group and four lithium chloride (LiCl) groups. Four LiCl groups were feed with food containing 3, 30, 300, 3000 mg/kg LiCl respectively. Control group was feed with normal food. By means of measuring the body weight, using Y-maze test and ABC immunohistochemistry, we observed the difference of the body weight gains and Y-maze training times of different groups, and the changes of CCK positive neurons in hippocampus.

Compared with control group, 3, 30 mg/kg LiCl groups could increase the body weight and improve the ability of learning and memory of rats(P < 0.01), however, these of the rats of 300, 3000 mg/kg group were lower (P < 0.05). The numbers of CCK positive neurons in hippocampus of 3, 30, 300 mg/kg groups were significantly increased compared with control group (P < 0.05), that of 3000mg/kg group was lower than control group (P < 0.05).

Low dose of lithium can improve the growth, the learning ability and the memory capacity obviously, but high dose of lithium could result in harmful effects.