title: Distribution of cholecystokinin-like immunoreactivity in the rat main olfactory bulb.
abstract: The anatomical localization of cholecystokinin-like immunoreactivity (CCK-I) within the rat main olfactory bulb was analyzed by using the peroxidase-antiperoxidase immunocytochemical technique. Neurons or neuronal processes containing CCK-I were localized within all laminae of the olfactory bulb except the olfactory nerve fiber layer. A large population of CCK-I neurons, with morphology, size, and distribution corresponding to that of the middle and external tufted cells, was observed within a zone extending from the deep periglomerular region through the superficial one-half to one-third of the external plexiform layer. A smaller number of immunoreactive perikarya were found in the deep external plexiform layer, the glomerular layer, and rarely within the inner plexiform layer. These CCK-I neurons appeared to correspond to internal tufted cells, periglomerular cells, and deep short-axon cells, respectively. Dense CCK-I staining of fibers and terminals was present within the internal plexiform layer and, less densely, within the neuropil of the granule cell layer. In addition, terminal-like CCK-I was localized within layer 1A of the anterior olfactory nucleus, the olfactory tubercle, and the most rostral piriform cortex. This observation provides corroboration for the identification of the principal CCK-I neuron in the rat olfactory bulb as the centrally projecting middle tufted cell. The present results, demonstrating the localization of CCK-I to both local circuit and projection neurons of the olfactory bulb and to terminal-like puncta in the internal plexiform and granule cell layers, suggest that CCK may be significantly involved in olfactory processing at several levels.
authors.forename: K B
authors.initials: KB
authors.lastname: Seroogy
authors.forename: N
authors.initials: N
authors.lastname: Brecha
authors.forename: C
authors.initials: C
authors.lastname: Gall
mesh_terms: D000818:Animals; D001369:Axons / Q000032:analysis; D001923:Brain Chemistry; D002766:Cholecystokinin / Q000032:analysis* / Q000276:immunology; D005260:Female; D007124:Immunoenzyme Techniques; D008297:Male; D009411:Nerve Endings / Q000032:analysis; D009474:Neurons / Q000032:analysis*; D009830:Olfactory Bulb / Q000166:cytology*; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000032:analysis; D014446:Tyrosine 3-Monooxygenase / Q000276:immunology
chemical_list: D002766:Cholecystokinin; D014446:Tyrosine 3-Monooxygenase