Direct and indirect action of flunarizine on vestibular activity.

Flunarizine administration (5 mg/Kg/os) in normal, labyrinthectomized and labyrinthectomized-cerebellectomized guinea pigs induced a depressant effect on spontaneous and evoked vestibular activities. Maximum effect was observed 90-120 min after drug administration and partial recovery at 180 min. Three different processes were involved: reduction of vestibular receptor excitability; direct inhibition of vestibular cells; inhibition of vestibular cells through strong activation of the cerebello-vestibular circuitry.