Development of cranial parasympathetic ganglia requires sequential actionsof GDNF and neurturin

The neurotrophic factors that influence the development and function of the parasympathetic branch of the autonomic nervous system are obscure, Recent ly, neurturin has been found to provide trophic support to neurons of the c ranial parasympathetic ganglion. Here we show that GDNF signaling via the R ET/GFR alpha1 complex is crucial for the development of cranial parasympath etic ganglia including the submandibular, sphenopalatine and otic ganglia. GDNF is required early for proliferation and/or migration of the neuronal p recursors for the sphenopalatine and otic ganglia. Neurturin exerts its eff ect later and is required for further development and maintenance of these neurons. This switch in ligand dependency during development is at least pa rtly governed by the altered expression of GFR alpha receptors, as evidence d by the predominant expression of GFR alpha2 in these neurons after gangli on formation.