Netrin-1 as a guidance molecule in the postnatal rat cochlea.

During synaptogenesis a number of growth factors and peptides control the guidance of auditory neuron (spiral ganglion neuron, SGN) axons to their target cells. Furthermore, evidence suggests that these factors exert their actions at discrete times and sites during development. This study demonstrates that the guidance molecule netrin-1 is expressed in the early postnatal rat cochlea, but shows decreasing expression with increasing age. These results suggest that netrin-1 may be involved in guiding axonal growth from SGNs for the onset of innervation, but is not required for maintenance of synaptic connections.