[Untitled]

Glial cell line-derived neurotrophic factor (GDNF), an important factor for developing and lesioned pre- and postganglionic sympathetic neurons, and its congeners signal through a receptor complex consisting of the tyrosine kinase c-Ret and a lipid-anchored alpha receptor (GFR alpha 1-4). Using in situ hybridization we show now that the mRNA for GFR alpha-2 is abundant in the adult rat adrenal medulla and its chromaffin cells. Coexpression of c-Ret and GFR alpha-1 mRNA's is restricted to a scarce subpopulation of medullary sympathetic neurons. Both GFR alpha-1 and GFR alpha-2 mRNA's are associated with preganglionic nerve trunks in the adrenal cortex. It is conceivable therefore that GDNF and related factors may activate chromaffin and preganglionic Schwann cells through a GFR-alpha receptor in absence of c-Ret.