Lamotrigine, a mood stabilizer, may have beneficial effects on memory acquisition and retrieval in mice

The aim of this study was to investigate the effects of a mood stabilizer lamotrigine (LMG) on learning and memory processes using Morris water maze (MWM), modified elevated plus maze (mEPM) and passive avoidance (PA) tests.

Balb-c mice were used. LMG were injected (20; 40mg/kg, intraperitoneal, i.p.) into mice before the probe trial of MWM test and before the acquisition session of mEPM and PA tests.

On the probe trial of MWM test, LMG (40mg/kg) significantly prolonged the "time spent in target quadrant" compared to control and LMG (20mg/kg). LMG (40mg/kg) decreased the "distance to platform" compared to control. Both doses of LMG did not change the "swim speed" of animals. In the mEPM test, in comparison of transfer latency on the first day and transfer latency on the second day for each group, transfer latency on the second day was significantly decreased in the control and LMG-treated groups. Second day transfer latencies compared in-between the group transfer latency of on second days significantly decreased by LMG (20mg/kg and 40mg/kg) treatment compared to control. In the PA test, retention latency significantly prolonged by LMG (40mg/kg) treatment compared to control and LMG (20mg/kg).

Our results may indicate that, LMG may have some ameliorating effects on spatial memory retrieval on the MWM test. LMG positively affected the acquisition of memory in the mEPM and in the PA test in naive mice.