Chronic social defeat stress: Impacts on ethanol-induced stimulation, corticosterone response, and brain monoamine levels

Autor(es)

Favoretto, Cristiane A. ^[1] ; Nunes, Yasmin C. ^[1] ; Macedo, Giovana C. ^[1] ; Rocha Lopes, Janaina Silva ^[1] ; Hartmann Quadros, Isabel M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Paulo UNIFESP, Dept Psychobiol, Rua Botucatu 862, 1st Floor, BR-04023062 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PSYCHOPHARMACOLOGY; v. 34, n. 4 JAN 2020.
• Citações Web of Science: 0

Resumo

Background: Chronic exposure to stress may dysregulate the hypothalamic-pituitary-adrenal axis and brain monoamine levels, contributing to the development of ethanol dependence. Exposure to chronic social defeat stress may impact ethanol-related effects, neural, and endocrine functions. Aim: This study assessed ethanol-induced locomotor activity, corticosterone responses, and brain monoamine levels in Swiss albino mice 10 days post-exposure to chronic social defeat stress. Methods: During a period of 10 days, male Swiss mice were exposed to daily defeat episodes, followed by housing with an aggressive mouse for 24 h. Control mice were housed in pairs and rotated every 24 h. Ten days post-stress, locomotor behavior was recorded after a challenge with ethanol (2.2 g/kg; intraperitoneal) or saline. After the test, blood and brain samples were collected for determination of plasma corticosterone and brain monoamines across different brain areas through high-performance liquid chromatography. Results: Defeated mice failed to show a stimulant locomotor response to ethanol, while controls displayed the expected ethanol-induced stimulation. Ethanol increased plasma corticosterone levels, with lower corticosterone secretion in defeated mice. Brain monoamines were affected by social defeat and ethanol, varying in different brain regions. Social stress reduced levels of dopamine, noradrenaline, and serotonin in the hypothalamus. Defeated mice presented reduced serotonin and dopamine levels in the frontal cortex. In the striatum, ethanol treatment increased dopamine levels in controls, but failed to do so in defeated mice. Conclusions: Our results suggest that chronic exposure to social defeat blunted ethanol-induced locomotor stimulation, and reduced ethanol-induced corticosterone secretion. Social stress promoted differential reductions in brain monoamine levels in the hypothalamus and frontal cortex and blunted ethanol-induced dopamine increases in the striatum. (AU)

• Processo FAPESP: 14/14623-2 - Consequências dos dois tipos de estresse de derrota social (episódica vs. contínua) sobre o efeito estimulante do etanol e sobre os níveis de monoaminas e corticosterona
• Beneficiário: Cristiane Aparecida Favoretto
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 16/04309-4 - Estresse de derrota social como modelo de depressão: efeitos comportamentais e neuroendócrinos
• Beneficiário: Yasmin Cristina Nunes
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 13/01562-2 - Efeitos da exposição crônica ao etanol ou ao estresse de derrota social sobre os efeitos estimulantes e reforçadores do etanol: envolvimento do sistema do CRF
• Beneficiário: Giovana Camila de Macedo
• Modalidade de apoio: Bolsas no Brasil - Doutorado