Two anatomically specific classes of candidate cholinoceptive neurons in the XXXX olfactory bulb.

@entity35 @entity4268 @entity1877 @entity1617
The pharmacohistochemical technique of Butcher (1978) and @entity1877 acetyltransferase ( @entity4268 ) immunocytochemistry were used to demonstrate the presence, morphology, and differential distribution of 2 classes of acetylcholinesterase (AChE)-positive, @entity4268 -negative neurons in the @entity35 olfactory bulb. One population of these neurons is located preferentially in a stratum just deep to the mitral cell layer (mcl). These AChE-positive intramitral neurons are significantly larger than the predominant inframitral neuronal type, the granule cell. Inframitral AChE-positive neurons appear to send processes deeper into the granule cell layer and superficially into the external plexiform layer (epl), above the mcl. Neurophysiological experiments reported in a companion article are consistent with the existence of a population of cholinoceptive neurons with the location and characteristics of these large inframitral interneurons. A second class of AChE-positive, @entity4268 -negative neurons is found exclusively in the glomerular layer. These neurons are located primarily in the periglomerular region and the superficial third of the epl; they are somewhat larger than typical periglomerular cells. Juxtaglomerular AChE neurons are smaller than inframitral AChE neurons. Since there are no neurons in the olfactory bulb that produce @entity4268 , the synthetic enzyme for @entity1617 , the AChE-positive cells reported here are hypothesized to be cholinoceptive neurons for the cholinergic projection from the basal forebrain to the olfactory bulb. Anatomical, physiological, and receptor-ligand binding data are consistent with this interpretation.
