ANTIDEPRESSANTS AND SIGNAL TRANSDUCTION IN BRAIN

抗抑郁药和大脑信号转导

• 批准号: 2415933
• 负责人: RONALD S. DUMAN
• 金额: $ 16.99万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2415933
• 关键词: MAO inhibitors; antidepressants; antisense nucleic acid; beta adrenergic receptor; biological signal transduction; cAMP response element binding protein; cyclic AMP; cyclic AMP receptors; drug administration rate /duration; electroconvulsive therapy; enzyme activity; frontal lobe /cortex; gene expression; growth factor receptors; in situ hybridization; laboratory rat; neuropharmacology; neurotrophic factors; northern blottings; protein kinase A; psychotropic drugs; receptor expression; serotonin inhibitor; serotonin receptor; stress; western blottings

Major depressive illness is alleviated by chronic, but not acute, administration of antidepressant drugs and electroconvulsive seizures (ECS). While the mechanism of action of these widely used treatments is not clearly understood, the delay in therapeutic efficacy has led to the hypothesis that some adaptive alteration in neuronal function must occur over the course of treatment. Preclinical and clinical studies support the hypothesis that the norepinephrine (NE) and serotonin (5-HT) neurotransmitter systems are involved in the therapeutic action of antidepressant treatments, but regulation of neurotransmitter levels and/or receptors cannot fully account for such actions. This is not surprising, since different types of antidepressants exert different effects on NE and 5-HT neurotransmitter systems. An updated hypothesis is that the actions of antidepressant treatments are mediated by adaptations of postreceptor, intracellular sites and regulation of gene expression. Our preliminary studies demonstrate that chronic, but not acute, administration of antidepressants increases levels of cAMP- dependent protein kinase (PKA) enzyme activity in particulate fractions, and levels of cAMP response element binding protein (CREB) immunoreactivity in rat frontal cortex. We have also found that antidepressant treatments increase levels of brain derived neurotrophic factor (BDNF) mRNA and its receptor, trkB, in frontal cortex and hippocampus, and that induction of BDNF is blocked by local infusion of CREB antisense, but not sense, oligonucleotides, providing a functional link between the PKA-CREB cascade and expression of BDNF. Based on these results, we hypothesize that antidepressant treatments activate the PKA- CREB cascade and increase expression of BDNF. To test this hypothesis, we will determine the influence of different types of antidepressant treatments, including electroconvulsive seizure, monoamine oxidase inhibitors, selective NE and 5-HT re-uptake inhibitors, and several atypical antidepressants on levels of PKA and CREB and expression of BDNF and trkB mRNA in rat limbic brain regions. The relevance and significance of these postreceptor adaptations will be verified by several criteria, including analysis of pharmacological specificity, determined by examination of nonantidepressant psychotropic drug treatments (haloperidol, cocaine, diazepam, and morphine), selective dose responses, time course, and regional specificity. PKA will be analyzed by standard enzyme assays and Western blot analysis, CREB immunoreactivity, both phosphorylated and dephosphorylated forms, will be determined by Western blot, CREB function will be determined by CRE gel shift analysis, and BDNF and trkB mRNA will be determined by RNase protection, northern blot, and in situ hybridization. Activation of the PKA-CREB cascade and induction of BDNF could mediate long-term adaptations of neuronal function in response to antidepressant treatments.

重度抑郁症可通过慢性而非急性缓解， 服用抗抑郁药物和电惊厥发作 （ECS）。虽然这些广泛使用的治疗方法的作用机制是 尚不清楚，治疗效果的延迟导致了 假设神经元功能必须发生一些适应性改变 在治疗过程中。临床前和临床研究支持 去甲肾上腺素 (NE) 和血清素 (5-HT) 的假设 神经递质系统参与治疗作用 抗抑郁治疗，但调节神经递质水平 和/或受体不能完全解释此类行为。这不是 令人惊讶的是，不同类型的抗抑郁药发挥不同的作用 对 NE 和 5-HT 神经递质系统的影响。更新的假设 抗抑郁治疗的作用是由 受体后、细胞内位点的适应和基因调控 表达。我们的初步研究表明，慢性但非 急性时，服用抗抑郁药会增加 cAMP- 的水平 颗粒部分中的依赖性蛋白激酶（PKA）酶活性， 和 cAMP 反应元件结合蛋白 (CREB) 的水平 大鼠额叶皮层的免疫反应性。我们还发现 抗抑郁治疗可增加脑源性神经营养物质的水平 BDNF 因子 mRNA 及其受体 trkB，位于额叶皮层和 海马体，并且 BDNF 的诱导被局部输注阻断 CREB ​​反义寡核苷酸，但不是有义寡核苷酸，提供功能性 PKA-CREB ​​级联与 BDNF 表达之间的联系。基于这些 结果，我们假设抗抑郁治疗激活 PKA- CREB ​​级联并增加 BDNF 的表达。为了检验这个假设， 我们将确定不同类型抗抑郁药的影响 治疗，包括电惊厥发作、单胺氧化酶 抑制剂、选择性 NE 和 5-HT 再摄取抑制剂以及多种 非典型抗抑郁药对 PKA 和 CREB ​​水平以及 BDNF 表达的影响 和 trkB mRNA 在大鼠边缘脑区域。相关性和意义 这些受体后适应将通过几个标准进行验证， 包括药理特异性分析，由 非抗抑郁精神药物治疗的检查 （氟哌啶醇、可卡因、地西泮和吗啡），选择性剂量反应， 时间进程和区域特殊性。 PKA将按标准进行分析 酶测定和蛋白质印迹分析、CREB ​​免疫反应性，两者 磷酸化和去磷酸化形式，将由 Western 测定 印迹，CREB功能将通过CRE凝胶位移分析确定，并且 BDNF 和 trkB mRNA 将通过 RNase 保护、Northern 印迹、 和原位杂交。 PKA-CREB ​​级联的激活和 BDNF 的诱导可以介导神经元的长期适应 功能对抗抑郁治疗作出反应。