Pre-treatment with a Ca2+ channel antagonist facilitates vestibular compensation.

A single injection of the Ca2+ channel antagonist verapamil (0.4 or 0.8 mg kg-1, i.m.) was given to adult guinea-pigs 1 h before a unilateral labyrinthectomy and the effects on the compensation of spontaneous ocular nystagmus (SN) were measured. At the 0.8 mg kg-1 dose, pre-treatment with verapamil significantly reduced SN frequency compared to saline controls; however, it also reduced the rate of SN compensation, resulting in no significant difference in the time required to reach maximal compensation. These results suggest the possibility that voltage-dependent Ca2+ channels may be involved in vestibular compensation.