Differential bulbar and extrabulbar projections of diverse olfactory receptor neuron populations in the adult @entity3392 ( XXXX ).

@entity12927 @entity18788 @entity460 @entity669 @entity4519 @entity18516 @entity3392
Immunohistochemical methods were used to characterize the expression of two @entity460 -binding proteins, calretinin (CR) and S100, in the olfactory rosette of the adult @entity3392 . These proteins are expressed in different sets of sensory neurons, and together represent a large proportion of these cells. Double immunofluorescence for CR and Ga(olf) protein, and CR immunoelectron microscopy, indicated that most CR-immunoreactive (ir) cells were ciliary neurons. Differential S100- and CR-ir projections to glomerular fields of the olfactory bulb were also observed, although these projections overlap in some glomeruli. Application of the @entity18788 dye @entity18516 to either S100-ir or CR-ir glomerular regions led to labeling of cells mostly similar to S100-ir and CR-ir neurons, respectively. Instead, these bulbar regions project to similar @entity4519 targets. On the other hand, antibodies against keyhole limpet hemocyanin (KLH)-stained numerous sensory cells in the olfactory rosette, including cells that were CR- and S100-negative. This antiserum also stained most primary bulbar projections and revealed extrabulbar olfactory primary projections coursing to the ventral area of the telencephalon through the medial olfactory tract. This extrabulbar projection was confirmed by tract-tracing with @entity18516 . A loose association of this extrabulbar primary olfactory projection and the catecholaminergic populations of the ventral area was also observed with double @entity669 hydroxylase/KLH-like immunohistochemistry. Comparison between KLH-like-ir pathways and the structures revealed by @entity12927 immunohistochemistry (a marker of terminal ganglion cells and fibers) indicated that the KLH-like-ir extrabulbar projection was different from the terminal nerve system. The significance of the extrabulbar olfactory projection of @entity3392 is discussed.
