title: Deletion of the Lsamp gene lowers sensitivity to stressful environmental manipulations in mice.
abstract: The Lsamp gene gives rise to limbic system-associated membrane protein (LAMP), which is expressed on the surface of somata and proximal dendrites of neurons. Lsamp-deficient mice have been shown to be slightly hyperactive in novel environments and less anxious, and they display alterations in swimming speed, fear reaction, fear conditioning and social behaviour. In human studies, links between the LSAMP gene and several psychiatric disorders have been found and LSAMP has been established as a tumour suppressor gene. To study the impact of environmental manipulations on the phenotype, we exposed male Lsamp-deficient mice to environmental enrichment (EE), a technique that has often been shown to abolish phenotypic deviations in knockout mice, and to social isolation, a stressful manipulation, after which all the mice were tested in a behavioural battery. EE abolished differences between the genotypes in body weight and anogenital sniffing, a behaviour related to aggressiveness, and amplified the anxiolytic-like phenotype of Lsamp-deficient mice both in the plus maze and motility box. Isolation abolished differences between the genotypes in body weight and anxiety and amplified the differences in swimming speed and anogenital sniffing. EE and isolation failed to modify the results as compared to standard housing in whisker trimming, locomotor activity, marble burying and corticosterone levels. In conclusion, Lsamp-deficient mice were less sensitive to isolation stress than their wild-type littermates. Lack of LAMP protein seemingly leads to a deterioration in the ability to adapt to novel stressful environments and stimuli.
authors.affiliation: Department of Physiology, University of Tartu, 19 Ravila Street, 50411 Tartu, Estonia. jurgen.innos@gmail.com
authors.forename: Jürgen
authors.initials: J
authors.lastname: Innos
authors.forename: Mari-Anne
authors.initials: MA
authors.lastname: Philips
authors.forename: Sirli
authors.initials: S
authors.lastname: Raud
authors.forename: Kersti
authors.initials: K
authors.lastname: Lilleväli
authors.forename: Sulev
authors.initials: S
authors.lastname: Kõks
authors.forename: Eero
authors.initials: E
authors.lastname: Vasar
mesh_terms: D000374:Aggression / Q000502:physiology / Q000523:psychology; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001835:Body Weight / Q000235:genetics / Q000502:physiology; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000502:physiology*; D003345:Corticosterone / Q000097:blood; D004777:Environment; D058851:GPI-Linked Proteins / Q000235:genetics / Q000502:physiology; D006120:Grooming / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D012934:Social Isolation / Q000523:psychology; D013315:Stress, Psychological / Q000097:blood / Q000235:genetics / Q000523:psychology*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D058851:GPI-Linked Proteins; C095362:limbic system-associated membrane protein; D003345:Corticosterone