DEVELOPMENTALLY-REGULATED EXPRESSION OF CGRP IN THE MOUSE OLFACTORY PATHWAY

The pattern of expression of the neuropeptide CGRP and its encoding mR NA has been determined by immunohistochemistry and in situ hybridizati on in the mouse olfactory pathway during development. Specific CGRP tr anscripts are first detected at E13 followed by the appearance of the peptide at E15. Both peptide and transcript are present until birth; t heir expression then appears to be down-regulated since postnatally th e peptide is only observed in some olfactory receptor neurons. A monoc lonal antibody that specifically recognizes the neurofilament subunit NF-M has been used in order to identify olfactory and trigeminal axons . Our results demonstrate that CGRP is expressed in olfactory neurons and their axons during development, thus supporting further its role a s a differentiation factor during olfactory bulb ontogenesis.