Assessment of gentamicin-induced vestibulotoxicity by click and galvanic vestibular-evoked myogenic potentials: A guinea pig investigation

作者：Cheng Po Wen; Lue June Horng; Lin Chi Te; Day An Shiou; Young Yi Ho^*

来源：NeuroToxicology, 2010, 31(1): 121-125.

DOI：10.1016/j.neuro.2009.10.009

• Galvanic vestibular stimulation
• Saccular macula
• Sodium channel Nav1.8
• Vestibular-evoked myogenic potential
• Vestibular ganglion

Objective: The aim of this investigation carried Out with guinea pigs was to study the possible effects of a gentamicin treatment on the saccular macula and on its afferent vestibular ganglion neurons.
Methods: The gentamicin-induced impairment was analyzed using vestibular-evoked myogenic potentials (VEMPs) elicited by both click and galvanic vestibular stimulations (GVS). Fifty mu l of saline or gentamicin solution (40 mg/ml) was dropped over the round window membrane of the right (control) and left (lesion) cochleae, respectively. Four weeks after Surgery, the VEMPs elicited with clicks and GVS were evaluated for each animal. Then, the animals were sacrificed in order to perform Morphological and anti-Nav1.8 immmunocytochemical analyses.
Results: Click- and GVS-VEMPs were obtained in all of the controls, whereas no potentials were obtained from gentamicin-treated animals. Lesions of sensory cells were observed in the saccular macula. In the injured vestibular ganglion, the percentage of voltage-gated sodium channel Nav-1.8-like immunoreactive (Nav1.8-Ll) neurons was significantly lower (38.9 +/- 0.7) than that (53.6 +/- 3.2) calculated in controls.
Conclusions: Gentamicin-induced impairments of the saccular macula and afferents of guinea pigs can be evaluated by recording both click- and GVS-VEMPs. Both tests provide information on the sacculo-collic reflex pathway and Could help a clinical diagnosis of gentamicin intoxication by conventional eardrops in the patient with a perforated eardrum.

• 出版日期2010-1