Levetiracetam reduces caffeine-induced Ca2+ transients and epileptiform potentials in hippocampal neurons.

ABSTRACT

The effect of the novel antiepileptic drug levetiracetam on caffeine (10 mM)-induced intracellular calcium ([Ca2+]i) response was investigated in rat hippocampal neurons in culture, with the aim of exploring the cellular mechanisms of this new drug. Levetiracetam significantly reduced caffeine-induced [Ca2+]i) response, with maximum inhibition at 32 microM. The R-enantiomer of levetiracetam, ucb L060, which is devoid of anticonvulsant activity, at 32 microM had no effect on caffeine-induced [Ca2+]i) response. Caffeine 10 mM also induced epileptiform field potentials in rat hippocampal slices single stimuli evoked repetitive population spikes and spontaneous field bursts regularly occurred. Levetiracetam (32 microM) significantly inhibited the amplitudes and the number of caffeine-induced repeated population spikes and delayed the appearance of spontaneous bursts, while ucb L060 (32 microM) completely lacked anti-caffeine activity. These results suggest that the inhibition of caffeine-induced Ca release from intra-neuronal stores might be an excitability-reducing effect of levetiracetam, contributing to its antiepileptic activity.