Mouse Magnetic-field Nystagmus in Strong Static Magnetic Fields Is Dependent on the Presence of Nox3.

ABSTRACT: HYPOTHESIS:Magnetic vestibular stimulation (MVS) elicits nystagmus in C57BL/6J mice but not head tilt mice lacking Nox3, which is required for normal otoconial development. BACKGROUND:Humans have vertigo and nystagmus in strong magnetic fields within magnetic resonance imaging machines. The hypothesized mechanism is a Lorentz force driven by electrical current entering the utricular neuroepithelium, acting indirectly on crista hair cells via endolymph movement deflecting cupulae. We tested an alternate hypothesized mechanism: Lorentz action directly on crista hair cell stereocilia, driven by their currents independent of the utricle. METHODS:Before MVS, vestibulo-ocular reflex responses of eight?C57BL/6J mice and six head tilt mice were measured during whole-body sinusoidal rotations and tilts using video-oculography. Mice were then placed within a 4.7 Tesla magnetic field with the horizontal semicircular canals approximately Earth-horizontal for ?1 minute in several head orientations, while eye movements were recorded via infrared video in darkness. RESULTS:Outside the magnet, both C57BL/6J and head tilt mice had intact horizontal vestibulo-ocular reflex, but only C57BL/6J mice exhibited static counter-roll responses to tilt (normal utiruclo-ocular reflex). When placed in the magnet nose-first, C57BL/6J mice had left-beating nystagmus, lasting a median of 32.8?seconds. When tail-first, nystagmus was right-beating and similar duration (median 28.0?s, p?>?0.05). In contrast, head tilt mice lacked magnetic field-induced nystagmus (p?

SUBMITTER: Ward BK 

PROVIDER: S-EPMC6241303 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature