ANTIDEPRESSANTS AND SIGNAL TRANSDUCTION IN BRAIN

严重的抑郁症可以通过慢性而不是急性缓解， 抗抑郁药物的使用和电惊厥发作 (ECS)。虽然这些广泛使用的治疗方法的作用机制是 目前尚不清楚，治疗效果的延迟导致了 假设神经功能必须发生某种适应性改变 在治疗过程中。临床前和临床研究支持 去甲肾上腺素和5-羟色胺的假说 神经递质系统参与血管内皮细胞瘤的治疗 抗抑郁治疗，但对神经递质水平的调节 和/或受体不能完全解释这种行为。这不是 令人惊讶的是，因为不同类型的抗抑郁药发挥不同的作用 对去甲肾上腺素和5-羟色胺神经递质系统的影响一个最新的假说 抗抑郁治疗的作用是由 受体后、细胞内部位的适应与基因调控 表情。我们的初步研究表明，慢性，但不是 急性，服用抗抑郁药会增加cAMP水平- 颗粒组分中的依赖蛋白激酶(PKA)酶活性， 和cAMP反应元件结合蛋白(CREB)水平 大鼠额叶皮质的免疫反应。我们还发现， 抗抑郁药物治疗增加脑源性神经营养水平 额叶皮质中脑源性神经营养因子(BDNF)mRNA及其受体TrkB的表达 脑源性神经营养因子的诱导可被局部注射阻断。 CREB反义，但不是正义的寡核苷酸，提供了一种功能 PKA-CREB级联反应与BDNF表达之间的联系。基于这些 结果，我们假设抗抑郁药物治疗激活了PKA- CREB级联反应增强BDNF的表达。为了检验这一假设， 我们将确定不同类型的抗抑郁剂的影响 治疗，包括电惊厥、单胺氧化酶 抑制剂，选择性去甲肾上腺素和5-羟色胺再摄取抑制剂，以及几种 非典型抗抑郁药对PKA、CREB水平及BDNF表达的影响 和TrkB基因在大鼠边缘脑区的表达。它的相关性和意义 这些受体后适应将通过几个标准进行验证， 包括药理专一性的分析，由 非抗抑郁药物精神药物治疗的现状与展望 (氟哌啶醇、可卡因、安定和吗啡)，选择性剂量反应， 时间进程和区域特异性。PKA将按标准进行分析 酶分析和Western印迹分析，CREB免疫反应性 磷酸化和去磷酸化形式，将由WESTERN确定 印迹、CREB功能将通过Cre凝胶位移分析来确定，以及 通过核糖核酸酶保护、Northern印迹、 和原位杂交。PKA-CREB级联的激活和 脑源性神经营养因子的诱导可介导神经元的长期适应 对抗抑郁药物治疗的反应。

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.