ODOR EXPOSURE REVEALS NONUNIFORM EXPRESSION PROFILES OF C-JUN PROTEININ RAT OLFACTORY-BULB NEURONS

In the main olfactory bulb, neurons are arranged strategically in dist inct layers among which translaminar synaptic transmission can be made from the superficial, sensory to the deep, output layers that account for the processing of olfactory information, To search for stimulus-t ranscription coupling thought ro be operated differentially in several cell types, c-Jun expression was examined immunohistochemically in ra t olfactory bulb following 30-min odor stimulation with acetic acid an d 1-butanol. c-Jun was rapidly induced in neuronal cell nuclei belongi ng to periglomerular, tufted, mitral and granule cells. The disappeara nce of c-Jun, however, differed between each cell type. In the glomeru lar layer, the glomeruli composed of c-jun-expressing periglomerular c ells were seen. Different odors led to labeling of different sets of g lomeruli. The labeled periglomerular cells disappeared within 2 h. In all the deeper layers, however, a rather homogeneous label was noted f or the tufted, mitral and granule cells present throughout the olfacto ry bulb, regardless of the difference in odor, In tufted and mitral ce lls, the c-jun expression persisted for 4 days after odor stimulation. In the granule cell layer, numerous granule cells increased c-Jun imm unoreactivity which lasted for 1 day following odor application. In co ntrol rats which were given clean air, the basal amount of c-Jun expre ssion was seen confined to scattered granule cells. The results sugges t that c-Jun is expressed in a variety of odorant-stimulated bulb neur ons with a time course being dependent on cell type. (C) 1997 Elsevier Science B.V.