Figure 1.

Neurite outgrowth in 6–14 DIV co-cultures from P3–8 rodents. In co-cultures of vestibular ganglion, crista (Cr), and utricle (U) from P5 mouse (A) or rat (B) pups, neurons extend processes toward the sensory epithelia. Neurofilaments (green) were stained with anti-N52 antibodies, hair cells (red) with anti-calretinin serum, and nuclei (blue) with ToPro3. The importance of extrinsic factors was highlighted in these culture conditions (C,D). BDNF added to the culture medium [P5 mice; (C)] enhances neurite outgrowth, but its presence in the culture medium disrupts with the natural directional attraction of neurites by the sensory epithelium. Neurites spread all over the culture plate (arrows) without preferential orientation as observed in (A) or (B). Staining of Schwann cells [P3 rats; (D), red, arrow heads] demonstrates their contribution to the process of neurite outgrowth toward sensory epithelia. Scale bars 100 μm.