Distinctive effects of unpredictable subchronic stress on memory, serum corticosterone and hippocampal BDNF levels in high and low exploratory mice.
Stress affects learning and memory processes and sensitivity to stress greatly varies between individuals. We studied behavioral and neurobiological effects of unpredictable subchronic stress (USCS) in two behavioral extremes of mice from the same strain (CF1) selected by their exploratory behavior of the central arena of an open field. The top and bottom 25% explorers were classified as low exploratory (LE) and high exploratory (HE) mice, respectively. The open field task, the novel object recognition task (NOR), sucrose intake and tail suspension task were evaluated in LE and HE groups exposed to USCS for two weeks or control conditions. Also serum corticosterone and hippocampal BDNF and S100B levels were analyzed. Both stressed groups exhibited less exploratory activity when submitted to USCS, but their difference in exploratory behavior remained. This short stress protocol did not induce changes in sucrose intake or immobility in the tail suspension task. Also, LE mice exhibited impaired NOR performance after USCS, whereas HE mice changed their pattern of exploration towards less exploration of the familiar object. HE had lower corticosterone levels than LE mice, but corticosterone levels increased after stress only in HE mice. Hippocampal BDNF in LE was lower than in HE but decreased after USCS only in HE mice, whereas S100B levels were not different between groups and did not change with USCS. In conclusion, our results suggest that individual differences in exploratory behavior in rodents from the same strain influence cognitive and biochemical response to stress.
Programa de Pós-Graduação em Ciências Biológicas/Bioquímica, Universidade Federal do Rio Grande do Sul, Instituto de Ciências Básicas da Saúde, Departamento de Bioquímica, Porto Alegre/RS, 90035-003, Brazil. vkghidini@gmail.com
Vanessa
V
Kazlauckas
Eduardo
E
Kalinine
Renata
R
Leke
Jean Pierre
JP
Oses
Fernanda
F
Nunes
Janaína
J
Espinosa
Sabrina
S
Mioranzza
Francisco
F
Lulhier
Luis V
LV
Portela
Lisiane O
LO
Porciúncula
Diogo R
DR
Lara
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D003345:Corticosterone / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005106:Exploratory Behavior / Q000502:physiology*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D008568:Memory / Q000502:physiology*; D051379:Mice; D010641:Phenotype; D013312:Stress, Physiological / Q000502:physiology*; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology*
D019208:Brain-Derived Neurotrophic Factor; D003345:Corticosterone