EXPRESSION OF GALANIN AND A GALANIN RECEPTOR IN SEVERAL SENSORY SYSTEMS AND BONE ANLAGE OF RAT EMBRYOS

Using in situ hybridization and immunohistochemistry the expression of , respectively, prepro-galanin (prepro-GAL) mRNA and GAL receptor-1 mR NA, as well as GAL-like and GAL message-associated peptide-like immuno reactivities, were studied in rats from embryonic day 14 (E14) to post natal day 1. GAL expression was observed already at E14 in trigeminal and dorsal root ganglion neurons and at E15 in the sensory epithelia i n developing ear, eye, and nose, as well as at E19 during bone formati on. Also, GAL receptor-1 mRNA was expressed in the sensory ganglia of embryos but appeared later than the ligand. These findings suggest tha t GAL and/or GAL message-associated peptide may have a developmental r ole in several sensory systems and during bone formation.