Separate signals mediate hypoglossal motor neuron response to axonal injury.

Nerve transection causes decreased choline acetyltransferase (ChAT) expression and appearance of nerve growth factor receptor (NGFr) in hypoglossal motor neurons. Topical application of vincristine to the hypoglossal nerve blocks axonal transport of WGA for more than one week and causes loss of ChAT but no appearance of NGFr. These results indicate that loss of ChAT is related to interruption of axonal transport, but another signal induces de novo expression of NGFr.