Improvement of Vestibular Plasticity in the Guinea Pig with a Calcium Entry Blocker

Abstract

The influence of flunarizine on vestibular compensation was investigated in hemilabyrinth-ectomized guinea pigs. The results showed that the vestibular deficits from hemilabyrinth-ectomy disappeared more rapidly in the treated animals than in the controls. To elucidate the mechanism by which the drug could affect the compensatory process, further studies on the spontaneous and evoked activity of vestibular nuclei were performed in normal, labyrinthectomized and labyrinthectomized-cerebellectomized animals. These electro-physiological data implied that flunarizine improved the vestibular compensation by inhibiting the receptor and nuclear activities of the intact labyrinth. The drug excited the cerebellar cortex, which modulated the activity of the vestibular nuclei of both sides, restoring the balance disrupted by hemilabyrinthectomy.

Key Words:

• compensation
• vestibular nuclei
• flunarizine