Branching of Spiral Ganglion Neurites Induced by Focal Application of Fibroblast Growth Factor-1

The study demonstrated that fibroblast growth factor-1 (FGF-1) played a significant role in the branching of spiral ganglion neurites during the development of the organ of Corti in rats. When FGF-1 was applied to polybead microspheres and placed near spiral ganglion neurites from postnatal day 4 rat samples, the neurites formed a plexus-like network with significantly higher branching near the FGF-1 beads. This branching did not occur near control beads without FGF-1, indicating that FGF-1 specifically induced this effect. The findings suggested that FGF-1 was crucial for the innervation and synaptogenesis of hair cells in the sensory epithelium during terminal development.