Alterations in monoamine levels and oxidative systems in frontal cortex, striatum, and hippocampus of the rat brain during chronic unpredictable stress

Abstract

Stress plays a key role in the induction of various clinical disorders by altering monoaminergic response and antioxidant defenses. In the present study, alterations in the concentrations of dopamine (DA), serotonin (5-HT) and their metabolites, and simultaneous changes in the antioxidant defense system and lipid peroxidation in different brain regions (frontal cortex, striatum, and hippocampus) were investigated immediately and 24 h after exposure to chronic unpredictable stress (CUS). CUS involved subjecting Sprague-Dawley rats to two different types of stressors varying from mild to severe intensity every day in an unpredictable manner, over a period of 7 days. CUS significantly decreased DA and 5-HT concentrations, with increased DA turnover ratios in the selected brain regions. In the frontal cortex and striatum, DA metabolite concentrations were increased; however, in the hippocampus they remained unaltered. Further, a decrease of 5-hydroxyindoleacetic acid content was observed in the frontal cortex and striatum, with no significant alteration in the hippocampus. CUS also reduced the activities of superoxide dismutase and catalase, with increased lipid peroxidation and decreased glutathione levels in the selected brain regions. Glutathione peroxidase activity was increased in the frontal cortex and hippocampus only. The pattern of CUS-induced monoamine and oxidative changes immediately after the last stressor and 24 h later were similar when compared with the control group, indicating that the observed changes were due to the chronic exposure to the various stressors and were not merely acute effects of the last stressor. The altered redox state in the striatum and frontal cortex might be related to the perturbed DA and/or 5HT levels, while the hippocampus seems to be less influenced by CUS in terms of monoamine metabolite changes. These results suggest that the perturbed monoamine levels could interact with the oxidative load during CUS. Hence, the current study has implications for pharmacological interventions targeting both central monoamines and cellular antioxidants as a potential stress management strategy for protecting against central stress-induced disorders.

Gastro-protective and Anti-stress Efficacies of Monomethyl Fumarate and a Fumaria indica Extract in Chronically Stressed Rats

“…Stressinduced alterations in the functions of monoaminergic and/ or HPA systems with subsequent enhancement of oxidative load are associated with a wide range of central and peripheral disorders (Zafir and Banu 2009;Ahmad et al 2010). Stressors activate the par ventricular nucleus, giving rise to the release of corticotropin-releasing hormone (CRH), and CRH acts on the pituitary and stimulate the secretion of ACTH, which promotes glucocorticoids release from the adrenal cortex (Herman and Cullinan 1997).…”

Effect of melatonin on antioxidant enzyme activities in blood erythrocytes of rats during acute emotional stress

“…В целом, изменения активности антиоксидантных ферментов в крови и структурах головного мозга пассивных животных, выявленные при иммобилизации с одновременным электрокожным раздражением, согласуются с данными, полученными на других моделях стрессорных нагрузок. Установлено, например, что активность ГП в биологических тканях у крыс возрастает при остром водно-иммерсионном стрессе, а также при чередовании эмоциогенных и физических стрессоров [6,24]. Обнаруженное в наших исследованиях отсутствие изменений функциональной активности ферментативного звена антиоксидантной защиты крови у поведенчески активных крыс, подвергнутых экспериментальной стрессорной нагрузке, иллюстрирует относительное постоянство оксидативного статуса тканей этих животных в условиях эмоционального стресса.…”

“…Элиминация свободнорадикальных частиц в организме осуществляется с помощью антиоксидантной системы, к которой относятся соединения, снижающие интенсивность окислительных процессов. Нарушение соотношения прооксидантов и антиоксидантов в тканях играет определяющую роль в развитии оксидативного стресса у млекопитающих [4][5][6]. Смещение прооксидантно-антиоксидантного равновесия с сопутствующим изменением интенсивности окислительно-восстановительных реакций в биологических мембранах и жидкостях может являться сигналом для запуска стрессорного ответа [7].…”

Alterations in phospholipidomic profile in the brain of mouse model of depression induced by chronic unpredictable stress

“…Also, the majority of lipid peroxidation products have pro inflammatory effects (Cohen, 2000, Black, 2002, Ahmad et al, 2010, Wielgat et al, 2011. Although, the pathophysiological alterations that triggers the association between chronic stress and depression are not completed understood, it is known that this association is characterized by an increase in cytokines/inflammation and oxidative stress with an increase in reactive oxygen species (Miller, 2010).…”