To know the influence of"high-potassium" of the perilymph on the labyrinthine and sensory cells function, the K+ -iontophoresis was performed for the right ear of 52 guinea pigs. In this experiment, the following results were obtained:
1) ENG study revealed at first irritative nystagmus, directed to the iontophoretic side, which was soon switched over paralytic nystagmus, directed to the unaffected side. This "2 phasic change of vestibular function" was proved by the measurement of succinate dehydrogenase-activity in the vestibular sensory cells. But, there was some delay between the reversal of nystagmusdirection and the change of enzyme activity. This delay suggested the influence of central efferent system.
2) There was no particular morphological change of the sensory cells of crista ampullaris in both irritative and paralytic stage (TEM).
3) ECoG study revealed the decrease of the action potential from the beginning, and the enzyme activity of the cochlear sensory cells was impaired without any irritative sign.
