Lamotrigine: Influence on the passive avoidance behavior in electroconvulsive shock-treated rats

The effects of various doses (1, 10 or 30 mg/kg) of lamotrigine (LTG) on the learning ability in rats exposed to electroconvulsive shock (ECS) were examined. The animals were trained in a passive avoidance procedure. LTG had been injected 30 min before the learning trial started. The ECS was given immediately after the learning trial response had been acquired. A passive avoidance retention test was performed 24 hours later. It was found that ECS strongly impaired the retention of the passive avoidance response. LTG did not influence the passive avoidance behavior in the sham ECS-treated group, but in the doses of 10 and 30 mg/kg was effective in reversing the memory deficit in ECS-treated rats. In conclusion, these findings support the hypothesis that perturbations in ionic homeostasis and excessive glutamate release can contribute to the memory deficit associated with ECS administration. Because of the antiamnestic effect, LTG can be an interesting candidate for clinical trials in patients with cognitive impairment caused by electroconvulsive therapy.