An in vitro preparation to access cellular and neuronal components in the mouse inner ear

An in vitro mouse temporal bone preparation has been developed in order to allow the investigation of structures and functions in a living hearing org an. Fluorescent vital probes (a potentiometric styryl dye, RH 795, and a vi tal dye staining cellular cytoplasm, calcein) were perfused through the sca la tympani to stain cellular components of the cochlea. Observations of the cochlear apical turn were performed using a confocal microscope. In spite of the anatomical constraints due to the small size of the mouse cochlea, d etailed images were obtained. The sensory cells as well as their innervatin g nerve fibres were clearly seen. Nerve fibres crossing the tunnel of Corti and projecting to the outer hair cells could also be visualised.