title: Substrain and light regime effects on integrated anxiety-related behavioral z-scores in male C57BL/6 mice-Hypomagnesaemia has only a small effect on avoidance behavior.
abstract: Magnesium (Mg) has been described to possess an anxiolytic function, but a number of studies present inconsistent results on this matter. In this study the effect of Mg deficiency on anxiety-related behavior, brain and blood plasma Mg in young adult male C57BL/6JOlaHsd and C57BL/6NCrl mice was studied. The animals were put on a control or Mg deficient diet from day 0 and significant hypomagnesaemia was evident from day 12 onwards in the test animals. Housing and test conditions were under either conventional light regime (white light behavioral test conditions) or reverse light regime (red light behavioral test conditions). The animals were tested in three tests for unconditioned anxiety: the modified Hole Board (day 14), the light-dark test (day 21) and the elevated plus maze (day 28). Overall integrated behavioral z-scores were calculated over these three behavioral tests. Mg showed a structure dependent distribution at the level of the brain, that differed between C57BL/6 substrain and light regime (conventional versus reverse), respectively. Likewise, total brain Mg did differ between substrain and light regime, but was not affected by the diet. Animals on the Mg deficient diet housed under conventional light regime had a higher final (day 28) blood plasma corticosterone level as compared to controls. Animals housed under reverse light regime exhibited no diet effect of plasma corticosterone levels. The significant hypomagnesaemia at blood plasma level resulted in an effect of Mg deficiency on avoidance, but not overall anxiety-related behavior. Significant differences regarding avoidance behavior were found between the two substrains and light regimes, respectively.
authors.affiliation: Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands; Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands. Electronic address: M.Labots@uu.nl.
authors.forename: M
authors.initials: M
authors.lastname: Labots
authors.affiliation: Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands. Electronic address: xchu.zheng@gmail.com.
authors.forename: X
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands. Electronic address: golnazmoattari@yahoo.com.
authors.forename: G
authors.initials: G
authors.lastname: Moattari
authors.affiliation: Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands. Electronic address: J.G.vantKlooster@uu.nl.
authors.forename: J G
authors.initials: JG
authors.lastname: Lozeman-Van't Klooster
authors.affiliation: Division of Behavioural Neuroscience, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands. Electronic address: J.M.Baars@uu.nl.
authors.forename: J M
authors.initials: JM
authors.lastname: Baars
authors.affiliation: Division of Behavioural Neuroscience, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands. Electronic address: p.hesseling@hotmail.com.
authors.forename: P
authors.initials: P
authors.lastname: Hesseling
authors.affiliation: Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands. Electronic address: marla.lavrijsen@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Lavrijsen
authors.affiliation: Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands. Electronic address: S.Kirchhoff@uu.nl.
authors.forename: S
authors.initials: S
authors.lastname: Kirchhoff
authors.affiliation: Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands; Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands. Electronic address: F.Ohl@uu.nl.
authors.forename: F
authors.initials: F
authors.lastname: Ohl
authors.affiliation: Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80166, 3508 TD Utrecht, The Netherlands; Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands. Electronic address: H.A.vanLith@uu.nl.
authors.forename: H A
authors.initials: HA
authors.lastname: van Lith
mesh_terms: D000221:Adaptation, Ocular; D000818:Animals; D001007:Anxiety / Q000209:etiology* / Q000235:genetics; D001362:Avoidance Learning / Q000502:physiology*; D001835:Body Weight; D001921:Brain / Q000378:metabolism / Q000473:pathology; D003345:Corticosterone / Q000097:blood; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*; D008274:Magnesium / Q000097:blood / Q000378:metabolism; D008275:Magnesium Deficiency / Q000097:blood / Q000150:complications* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D011897:Random Allocation; D018709:Statistics, Nonparametric
chemical_list: D008274:Magnesium; D003345:Corticosterone
keywords: Anxiety-related behavior; C57BL/6; Hypomagnesaemia; Inbred mouse substrains; Light regime; Magnesium