Social isolation stress: role of neurosteroids in the action of ethanol on GABAAR

社会隔离压力：神经类固醇在乙醇对 GABAAR 作用中的作用

• 批准号: 7215946
• 负责人: GIOVANNI BIGGIO
• 金额: $ 9万
• 依托单位: UNIVERSITY OF CAGLIARI
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-15 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7215946
• 关键词: Acute; Aggressive behavior; Alcohol abuse; Alcohol consumption; Alcohols; Amygdaloid structure; Animal Model; Animals; Anxiety; Behavioral; Boutos; Brain; Breathing; Candidate Disease Gene; Cells; Characteristics; Chronic; Condition; Ethanol; Gene Expression; Goals; Head; Hippocampus (Brain); Immunohistochemistry; Laboratory Animals; Literature; Measures; Mediating; Mediator of activation protein; Mental Depression; Modeling; Molecular; Motor Activity; Mouse Strains; Mus; Neurons; Outcome Study; Plasma; Plastics; RNase protection assay; Radioimmunoassay; Rattus; Receptor Gene; Research; Research Personnel; Rodent; Role; Slice; Social isolation; Steroid biosynthesis; Steroids; Stimulus; Stress; Urination; Work; alcohol effect; brain tissue; drinking; drinking behavior; hypothalamic-pituitary-adrenal axis; insight; neurotransmission; patch clamp; receptor; receptor function; response; social stress; vapor

DESCRIPTION (provided by applicant): Recently, it has been proposed that certain effects of ethanol could be mediated by an increase in the brain levels of neuroactive steroids, such as 3a,5a-THP, which has the ability to increase at nanomolar concentrations the GABAA receptor function. Ethanol-induced increase in neuroactive steroid concentrations appear to result from stimulation of the hypothalamic-pituitary-adrenal (HPA) axis, and at least in part, from a direct stimulation of brain eurosteroidogenesis. Social isolation is a model of prolonged mild stress that has been shown to be associated to marked behavioral alterations, such as increased locomotor activity, anxiety, depression, and aggressiveness in laboratory animals. Social isolation results in a decrease in the brain and plasma concentrations of neuroactive steroids, and is accompanied by an abnormal response to acute stressful stimuli as well as by an increased neurosteroidogenic effect induced by the acute administration of ethanol. We intend to use social isolation in C57BL/6J mouse strain as a model of prolonged mild stress in which to investigate further the role of neurosteroids in the acute and chronic actions that ethanol exerts on the function of GABAA receptors in the hippocampus and amygdala and the interplay with stress. In socially isolated mice, we will measure the effects of ethanol in the following experimental condition: i) after acute administration; ii) after chronic exposure by vapor inhalation, and iii) in a free-choice drinking paradigm in order to establish if this condition can increase ethanol consuption. Neurosteroid levels in brain tissue will be assessed by RIA. GABAA receptor gene expression by RNase protection assay, and by immunohistochemistry. GABAA receptor function will be examined by conventional whole-cell patch clamp recording in brain slices. This project, if successful, by employing the social isolation stress will help to understand further the role of neurosteroids as endogenous mediators of certain pharmacological actions of ethanol as well as the molecular mechanisms underlying the neuronal plastic adaptive changes induced by stress and the interplay with ethanol consumption. Given that many stressful, as well as physiopathological, conditions such as PMS, depression and anxiety could be associated to marked fluctuations in plasma and brain concentrations of neurosteroids, the outcome of this study will provide additional insights about the vulnerability to ethanol abuse, characteristic of such conditions.

描述（由申请人提供）：最近，有人提出，乙醇的某些作用可以通过增加大脑中神经活性类固醇（例如 3a,5a-THP）的水平来介导，3a,5a-THP 能够在纳摩尔浓度下增强 GABAA 受体功能。乙醇引起的神经活性类固醇浓度增加似乎是由于刺激下丘脑-垂体-肾上腺（HPA）轴，并且至少部分是由于直接刺激大脑欧洲类固醇生成。社会隔离是一种长期轻度压力的模型，已被证明与实验动物的显着行为改变有关，例如运动活动增加、焦虑、抑郁和攻击性。社会隔离会导致大脑和血浆中神经活性类固醇的浓度降低，并伴有对急性应激刺激的异常反应以及急性服用乙醇引起的神经类固醇生成作用的增加。我们打算使用 C57BL/6J 小鼠品系的社会隔离作为长期轻度应激的模型，进一步研究神经类固醇在乙醇对海马和杏仁核 GABAA 受体功能的急性和慢性作用中的作用以及与应激的相互作用。在社会隔离的小鼠中，我们将在以下实验条件下测量乙醇的影响：i）急性给药后； ii) 通过蒸气吸入长期暴露后，以及 iii) 在自由选择饮酒模式中，以确定这种情况是否会增加乙醇消耗量。脑组织中的神经类固醇水平将通过 RIA 进行评估。通过 RNase 保护测定和免疫组织化学检测 GABAA 受体基因表达。 GABAA 受体功能将通过脑切片中的传统全细胞膜片钳记录进行检查。该项目如果成功，通过利用社会隔离压力，将有助于进一步了解神经类固醇作为乙醇某些药理作用的内源性介质的作用，以及压力引起的神经元可塑性适应性变化的分子机制以及与乙醇消耗的相互作用。鉴于许多压力和病理生理状况，如经前综合症、抑郁和焦虑，可能与血浆和大脑中神经类固醇浓度的显着波动有关，这项研究的结果将为了解乙醇滥用的脆弱性（此类状况的特征）提供更多见解。