Novel long-term anticonvulsant treatment with gabapentin without causing memory impairment in mice

We previously reported that administration of a single dose of gabapentin (GBP) immediately after training improves memory of mice in an inhibitory avoidance task (IA), whereas GBP administered repeatedly for 7 days impairs memory. This is in accordance with the observation that long-term clinical treatment with GBP may be associated with adverse cognitive side effects. In the present work we used a GBP-loaded poly(ε-caprolactone) implant, allowing controlled release of the drug and maintenance of constant plasma levels over 1 week. When GBP-loaded implants were inserted subcutaneously into mice, immediately after training in the IA task, memory consolidation was enhanced. Moreover, GBP released from implants had an anticonvulsant action against pentylenetetrazole-induced seizures. These results suggest that maintenance of stable GBP plasma levels could protect against seizures without causing memory impairment. Hence, the adverse cognitive effects might be avoided by stabilizing plasma levels of the drug.