Expression of GFR alpha-1, GFR alpha-2 and c-Ret mRNAs in rat adrenal gland

Glial cell line-derived neurotrophic factor (GDNF), an important factor for developing and lesioned pre- and postganglionic sympathetic neurons, and i ts congeners signal through a receptor complex consisting of the tyrosine k inase 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 i n 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 med ullary sympathetic neurons. Both GFR alpha -1 and GFR alpha -2 mRNA's are a ssociated with preganglionic nerve trunks in the adrenal cortex. It is conc eivable therefore that GDNF and related factors may activate chromaffin and preganglionic Schwann cells through a GFR-alpha receptor in absence of c-R et.