Labelling of olfactory bulb glomeruli following horseradish peroxidase lavage of the nasal cavity

The transport of horseradish peroxidase (HRP) from the nasal cavity to the olfactory bulb was examined in rat. HRP was present primarily in the olfactory nerve and glomerular layer. In some animals the glomeruli were densely filled with product while in others there was considerable interglomerular variation in density. Examination of the decalcified noses revealed a restricted distribution of HRP in those rats with partially labelled olfactory bulbs. The presence of small groups of densely labelled glomeruli was also noted using the 2-deoxyglucose method to examine odor-induced metabolic activity.