Chemical anatomy of the macaque monkey olfactory bulb: NADPH-diaphorase/Nitric oxide synthase activity

The distribution and the morphology of nicotinamide adenine dinucleotide ph osphate (NADPH)-diaphorase (ND)-active and neuronal nitric oxide synthase ( NOS)-immunoreactive neurons and fibers were studied in the olfactory bulb o f three species of primates, i.e., the cynomolgus macaque monkey (Macaca fa scicularis), the Japanese macaque monkey (Macaca fuscata), and the pig-tail macaque monkey (Macaca nemestrina). The ND staining was carried out by mea ns of a direct histochemical method with beta-NADPH as cosubstrate and nitr o blue tetrazolium as chromogen. The NOS immunostaining was carried out by using a polyclonal antibody and the avidin-biotin peroxidase method. Simila r results were found in the three species, where a distinct distribution pa ttern of ND/NOS-stained neurons and fibers was observed. All olfactory fibe rs demonstrated ND-positive labeling but they were NOS-immunonegative. In t he superficial modulatory area of the olfactory bulb, a few weakly ND-and N OS-positive periglomerular cells, stellate cells, and darkly stained superf icial short-axon cells were observed. In the inframitral layers, granule ce lls, deep stellate cells, and deep short-axon cells were distinguished. Sho rt-axon cells had oriented morphologies and spiny dendrites. Many thick, va ricose ND/NOS-stained fibers identified as centrifugal fibers were observed in the white matter, granule cell layer, internal plexiform layer, mitral cell layer, and external plexiform layer. This distribution of ND activity and NOS immunoreactivity showed similarities to and differences from what h as been reported in the olfactory bulb of macrosmatic mammals including rod ents (rat, mouse, and hamster) and insectivores (hedgehog). These data conf irm that the complexity of the ND/NOS staining in the olfactory bulb of one species correlates with the importance of olfaction in the biology of such species. J. Comp. Neurol. 402:419-434, 1998. (C) 1098 Wiley-Liss, Inc.