title: Glomerulus development in the absence of a set of mitral-like neurons in the insect olfactory lobe.
abstract: Mitral cells are the first neurons in the mammalian olfactory bulb to synapse with olfactory receptor axons during glomerulus development, and in an invertebrate, the moth Manduca sexta, mitral-like neurons overlap very early with olfactory receptor axons as they begin to form protoglomeruli. The possibility for early interaction between receptor neurons and mitral-like neurons led us to ask whether such an interaction plays an essential role in glomerulus development. In the current study in the moth, we surgically removed a major class of these mitral-like neurons before glomeruli began to form and asked: (a) Is the formation of the array of olfactory glomeruli triggered by an interaction of the first-arriving receptor axons with the dendrites of mitral-like neurons? (b) At the level of individual glomeruli, must the mitral-like dendrites be in place either to maintain receptor axons in a glomerular arrangement, or to guide later-growing dendrites of other types into the developing glomeruli? Our results indicate that even without the participation of this group of mitral-like neurons, the array of sexually isomorphic ordinary glomeruli forms and the basic substructure of individual glomeruli develops apparently normally. We conclude that the mitral-like neurons in Manduca are not essential for the formation of ordinary olfactory glomeruli during development.
authors.affiliation: Arizona Research Laboratories, University of Arizona, Tuscon 85721, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Oland
authors.forename: L P
authors.initials: LP
authors.lastname: Tolbert
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D018402:Manduca / Q000033:anatomy & histology* / Q000254:growth & development*; D018613:Microscopy, Confocal; D009474:Neurons / Q000502:physiology; D009833:Olfactory Pathways / Q000166:cytology* / Q000254:growth & development*; D009435:Synaptic Transmission / Q000502:physiology