Enhancement of social isolation-induced aggressive behavior of young mice by zinc deficiency.
Neuropsychological behavior via activation of the hypothalamic-pituitary-adrenal (HPA) axis was analyzed using young mice fed a zinc-deficient diet for 2 weeks. Serum corticosterone concentration was significantly increased after 2-week zinc deprivation, whereas zinc concentration in the brain was not decreased. In the resident-intruder test, the rate of mice that exhibited aggressive behavior to the total mice was significantly higher in isolated zinc-deficient mice than in isolated control mice. The duration of aggressive behavior was more in isolated zinc-deficient mice. These results indicate that aggressive behavior of young mice elicited by social isolation is enhanced by zinc deficiency. On the other hand, social isolation-induced aggressive behavior was enhanced in isolated pair-fed mice with food restriction that can activate the HPA axis. Serum corticosterone concentration was also significantly higher in isolated zinc-deficient mice. To see the effect of the increased serum corticosterone on behavioral abnormality, neurotransmitter concentrations in brain tissue were checked. The concentrations of glutamate and GABA in brain tissue were significantly higher in both grouped and isolated zinc-deficient mice. Furthermore, the concentration of extracellular glutamate in the amygdala before the resident-intruder test was significantly higher in isolated zinc-deficient (aggressive) mice and the higher concentration was maintained during the test. The changes in neurotransmitter homeostasis, probably via the increase in serum corticosterone, seem to be linked to aggressive behavior elicited by social isolation in zinc deficiency.
Takeda
Atsushi
A
Department of Medical Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan. takedaa@u-shizuoka-ken.ac.jp
Tamano
Haruna
H
Kan
Fumika
F
Hanajima
Tomoyuki
T
Yamada
Kohei
K
Oku
Naoto
N
D000374:Aggression / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D003345:Corticosterone / Q000097:blood; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D006120:Grooming / Q000502:physiology; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D051379:Mice; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects; D018377:Neurotransmitter Agents / Q000378:metabolism; D012934:Social Isolation; D015032:Zinc / Q000097:blood / Q000172:deficiency*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D018690:Excitatory Amino Acid Agonists; D018377:Neurotransmitter Agents; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D015032:Zinc; D007608:Kainic Acid; D003345:Corticosterone