title: Compensation of depleted neuronal subsets by new neurons in a local area of the adult olfactory bulb.
abstract: In the olfactory bulb (OB), loss of preexisting granule cells (GCs) and incorporation of adult-born new GCs continues throughout life. GCs consist of distinct subsets. Here, we examined whether the loss and incorporation of GC subsets are coordinated in the OB. We classified GCs into mGluR2-expressing and -negative subsets and selectively ablated mGluR2-expressing GCs in a local area of the OB with immunotoxin-mediated cell ablation method. The density of mGluR2-expressing GCs showed considerable recovery within several weeks after the ablation. During recovery, an mGluR2-expressing new GC subset was preferentially incorporated over an mGluR2-negative new GC subset in the area of ablation, whereas the preferential incorporation was not observed in the intact area. The area-specific preferential incorporation of mGluR2-expressing new GCs occurred for BrdU analog- and retrovirus-labeled adult-born cells as well as for neonate-derived transplanted cells. The mGluR2-expressing new GCs in the ablated area were synaptically incorporated into the local bulbar circuit. The spine size of mGluR2-expressing new GCs in the ablated area was larger than that of those in the intact area. In contrast, mGluR2-negative new GCs did not show ablated area-specific spine enlargement. These results indicate that local OB areas have a mechanism to coordinate the loss and incorporation of GC subsets by compensatory incorporation of new GC subsets, which involves subset-specific cellular incorporation and subset-specific regulation of spine size.
authors.affiliation: Department of Physiology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Koshi
authors.initials: K
authors.lastname: Murata
authors.forename: Maki
authors.initials: M
authors.lastname: Imai
authors.forename: Shigetada
authors.initials: S
authors.lastname: Nakanishi
authors.forename: Dai
authors.initials: D
authors.lastname: Watanabe
authors.forename: Ira
authors.initials: I
authors.lastname: Pastan
authors.forename: Kazuto
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nihira
authors.forename: Hideki
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Shuichi
authors.initials: S
authors.lastname: Yamada
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mori
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001973:Bromodeoxyuridine / Q000378:metabolism; D064032:Calbindin 2; D002452:Cell Count / Q000379:methods; D002465:Cell Movement / Q000502:physiology; D017690:Cell Transplantation / Q000502:physiology; D002552:Cerebral Ventricles / Q000166:cytology / Q000601:surgery; D049229:Dendritic Spines / Q000502:physiology; D003857:Deoxyuridine / Q000031:analogs & derivatives / Q000378:metabolism; D000089622:Doublecortin Domain Proteins; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D007065:Idoxuridine / Q000378:metabolism; D000922:Immunotoxins / Q000633:toxicity; D020287:In Situ Nick-End Labeling / Q000379:methods; D053645:Interleukin-2 Receptor alpha Subunit / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D055495:Neurogenesis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D009474:Neurons / Q000145:classification* / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D009479:Neuropeptides / Q000378:metabolism; D009830:Olfactory Bulb / Q000166:cytology* / Q000187:drug effects; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D018709:Statistics, Nonparametric; D013569:Synapses / Q000502:physiology; D013997:Time Factors; D014161:Transduction, Genetic / Q000379:methods; D050598:Vesicular Glutamate Transport Protein 1 / Q000378:metabolism
chemical_list: D064032:Calbindin 2; D000089622:Doublecortin Domain Proteins; D000922:Immunotoxins; D053645:Interleukin-2 Receptor alpha Subunit; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D018094:Receptors, Metabotropic Glutamate; D064030:S100 Calcium Binding Protein G; D050598:Vesicular Glutamate Transport Protein 1; C413663:fluorescent protein 583; C526011:mPlum protein, Discosoma; C108822:metabotropic glutamate receptor 2; D049452:Green Fluorescent Proteins; C012244:5-chloro-2'-deoxyuridine; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2; D001973:Bromodeoxyuridine; D007065:Idoxuridine; D003857:Deoxyuridine