Role of inferior colliculus in vestibular vertigo induced by water caloric irrigation.

Vestibular vertigo is a common clinical symptom; however, the central neural mechanism of it is still poorly understood. To demonstrate the changes of neural excitability and ascorbate in inferior colliculus (IC) in a rat vertigo model induced by water caloric irrigation. In vertigo model induced by water caloric irrigation, we recorded the changes of spontaneous firing rate (SFR) of IC. Then a technique that combining microanalysis with an online electrochemical system (OECS) was employed to monitor the changes of extracellular ascorbate in IC. Electrophysiological studies showed that after vestibular ice water stimulation, the level of SFR in IC significantly increased, reaching (989 ± 9) % and (941 ± 62) % respectively at 2.0 h after contralateral ice water vestibular stimulation and ipsilateral ice water vestibular stimulation. However, the level of ascorbate in IC dramatically decreased after ice stimulation, decreased to (30 ± 12) % and (57 ± 24) % of the basal level respectively in the contralateral group and ipsilateral group. These findings suggest that inferior colliculus plays a role in peripheral vertigo, which would appear useful for uncovering neural mechanisms of vertigo and help finding novel therapeutic targets for vertigo.