title: Impaired fear memory and decreased hippocampal neurogenesis following olfactory bulbectomy in rats.
abstract: It has been proposed that a decrease in adult hippocampal neurogenesis provides a biological and cellular basis for major depression. The olfactory bulbectomy (OB) in rats is widely accepted as an animal model of depression. In the present study, we investigated the effect of OB on memory formation in the memory tasks related to the hippocampal function and adult hippocampal neurogenesis. OB induced a behavioural syndrome, which was characterized by an increased activity in the open-field test and impairment in passive avoidance behaviour and contextual fear conditioning. The behavioural changes, following OB, were accompanied by a decrease in the number of proliferating cells in the dentate gyrus. Furthermore, the differentiation of the newly born cells, into mature calbindin-positive neurons, was also retarded. Stereological analysis revealed a decrease in the total granule neuron numbers within the granule cell layer of the dentate gyrus, without a significant decrease in volume of the dentate gyrus. Although a relationship between altered neurogenesis and behavioural syndrome, induced by OB, is not established yet, our results suggest that decreased neurogenesis might at least partly contribute for behavioural deficits following OB.
authors.affiliation: Department of Pharmacology, University of Tartu, 51014 Tartu, Estonia.
authors.forename: Külli
authors.initials: K
authors.lastname: Jaako-Movits
authors.forename: Alexander
authors.initials: A
authors.lastname: Zharkovsky
mesh_terms: D000818:Animals; D000963:Antimetabolites; D001362:Avoidance Learning / Q000502:physiology; D001973:Bromodeoxyuridine; D002452:Cell Count; D016923:Cell Death / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D003213:Conditioning, Psychological / Q000502:physiology; D003594:Cytoplasmic Granules / Q000502:physiology; D018891:Dentate Gyrus / Q000166:cytology / Q000502:physiology; D005239:Fear / Q000502:physiology* / Q000523:psychology; D006624:Hippocampus / Q000166:cytology*; D008297:Male; D008568:Memory / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009830:Olfactory Bulb / Q000502:physiology*; D010641:Phenotype; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000963:Antimetabolites; D001973:Bromodeoxyuridine