SEGREGATED DISTRIBUTION OF NITRIC-OXIDE SYNTHASE-POSITIVE CELLS IN THE PERIGLOMERULAR REGION OF TYPICAL AND ATYPICAL OLFACTORY GLOMERULI

Using double-staining techniques, the distribution of NADPH-diaphorase (ND)- and nitric oxide synthase (NOS)-positive cells was compared in the periglomerular region of typical and atypical rat olfactory glomer uli. Dorsomedial and ventrolateral atypical glomeruli contained simila r number of ND/NOS-positive periglomerular cells. The number of ND/NOS -stained periglomerular cells was much higher (P < 0.001) in typical t han in atypical glomeruli. The present results indicate that, in addit ion to described neurochemical and ultrastructural differences between the neuropile of typical and atypical glomeruli, there are also marke d differences in the phenotype of periglomerular interneurons of both glomerular subsets.