RECEPTOR EXPRESSION IN OLFACTORY NEURONS DURING RAT DEVELOPMENT - IN-SITU HYBRIDIZATION STUDIES

In situ hybridization approaches have been employed to explore the ons et and time course of odorant receptor expression during the prenatal development of rats. The critical phase for the maturation of the olfa ctory system from embryonic day (E) 12 to E18 was analysed. The onset of expression of four receptor genes (OR5, OR14, OR37 and OR124) was f ound between day E12 and E14. In the early phase of development (E14) a distinct receptor subtype was expressed only in a few hundred neuron s; the number increased about two- to three-fold within a 2 day interv al. From the very beginning, spatial segregation of receptor subtypes in distinct expression zones was observed.