Lamotrigine and carbamazepine affect differently the release of D-[H-3]Aspartate from mouse cerebral cortex slices: Involvement of NO

The effects of lamotrigine and carbamazepine on the release of preloaded D- [H-3]aspartate and the involvement of nitric oxide were studied with mouse cerebral cortical slices in a superfusion system. Lamotrigine inhibited the veratridine-evoked release, whereas the K+-stimulated release was attenuat ed more strongly by carbamazepine than by lamotrigine. These effects were a ccentuated by the N-methyl-D-aspartate receptor antagonist L-2-amino-5-phos pbonovalerate and the nitric oxide synthase inhibitor L-nitroarginine, but diminished by the nitric oxide donor sodium nitroprusside. The results show that in addition to the blockade of voltage-sensitive Na+ (and Ca2+) chann els, NO-mediated mechanisms are probably involved in the anticonvulsant act ions of carbamazepine and, in particular, those of lamotrigine.