Abstract

Annona senegalensis Pers. is a plant used in Burkina folkloric medicine for the treatment of epilepsy. The stem-bark, roots and leaves of A. senegalensis are used for an array of human disorders, including epilepsy. Previous studies have demonstrated some genuine effects of A. senegalensis fractions in vivo models of temporal lobe epilepsy. In the present work, we have compared the pharmacological profile of the most promising A. senegalensis fraction obtained up-to-date with anticonvulsant drugs targeting voltage-activated channels namely Carbamazepine (Na+ channels) and Retigabine (KCNQ Channels). In an in vitro model of temporal lobe epilepsy, we could observe a dose-dependent reduction of electrically evoked epileptiform bursts in the CA1 region of the rat hippocampus when applying carbamazepine, retigabine or the F4 fraction of A. senegalensis. The intrinsic excitability of CA1 pyramidal neurons was dose-dependently reduced by A. senegalensis. Since A. senegalensis effects could not anymore be observed when endogenous voltage-dependent sodium channels were blocked and intrinsic excitability restored with a dynamic clamp amplifier, it was concluded that A. senegalensis contains molecules that target voltage-dependent sodium channels.

Key words: Hippocampus, epilepsy, Annona senegalensis, Burkina Faso plant extracts, sodium channel, KCNQ channel, M-current, retigabine, carbamazepine.

Abbreviation

PTX, Picrotoxin; Vm, membrane potential.