Alves Cecília Juliana, Magalhães Ana, Summavielle Teresa, Melo Pedro, De Sousa Liliana, Tavares Maria Amélia, Monteiro Pedro R R
IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
Ann N Y Acad Sci. 2008 Oct;1139:366-73. doi: 10.1196/annals.1432.047.
The use of cocaine in adults has been linked to depression and/or anxiety. Several studies have shown an association between cocaine-primed craving and depressive symptoms. In animal models, the forced swim test (FST) is frequently used for screening depressive-like behavior. This study aimed to verify the presence of depression-like symptoms in adolescent rats after chronic cocaine exposure by analyzing behavior in a FST. The subsequent alterations in neurotransmitters and hypothalamus-pituitary-adrenal axis activity induced by this test were also analyzed. Both male and female adolescent Wistar rats were submitted to a chronic "binge" pattern of administration of cocaine hydrochloride, and subjects were tested in a forced swim test 2 days after cocaine's last administration. At the end of the behavioral test, trunk blood was collected for quantification of corticosterone plasma levels, and hypothalamus, prefrontal cortex, amygdala, and hippocampus were dissected for neurochemical determinations. No significant differences were found in the behavior on the FST of both males and females after withdrawal from chronic cocaine administration. Nevertheless, plasma levels of corticosterone were increased in cocaine-treated males, although not significantly (P= 0.065). In females cocaine failed to affect corticosterone levels. Of interest, neurochemical analyses showed that dopamine turnover was decreased in amygdala in cocaine-treated males (not significantly, P= 0.055). No significant differences were found on neurotransmitter levels in the other brain regions analyzed. Withdrawal from chronic cocaine administration during adolescence did not have a significant effect on stress-induced behavioral alterations, although the neurochemical response to the stressful situation provided by FTS seemed to be affected.
成人使用可卡因与抑郁和/或焦虑有关。多项研究表明，可卡因引发的渴望与抑郁症状之间存在关联。在动物模型中，强迫游泳试验（FST）常用于筛查类似抑郁的行为。本研究旨在通过分析FST中的行为来验证慢性可卡因暴露后青春期大鼠是否存在类似抑郁的症状。还分析了该试验引起的神经递质和下丘脑 - 垂体 - 肾上腺轴活动的后续变化。将雄性和雌性青春期Wistar大鼠都给予盐酸可卡因的慢性“暴饮暴食”给药模式，并在可卡因最后一次给药后2天在强迫游泳试验中对受试动物进行测试。行为测试结束时，采集躯干血以定量血浆皮质酮水平，并解剖下丘脑、前额叶皮质、杏仁核和海马进行神经化学测定。在从慢性可卡因给药中撤药后，雄性和雌性在FST中的行为均未发现显著差异。然而，可卡因处理的雄性大鼠血浆皮质酮水平升高，尽管不显著（P = 0.065）。在雌性大鼠中，可卡因未能影响皮质酮水平。有趣的是，神经化学分析表明，可卡因处理的雄性大鼠杏仁核中的多巴胺周转率降低（不显著，P = 0.055）。在分析的其他脑区中，神经递质水平未发现显著差异。青春期从慢性可卡因给药中撤药对压力诱导的行为改变没有显著影响，尽管FTS提供的应激情况下的神经化学反应似乎受到了影响。
