ANTIDEPRESSANTS AND SIGNAL TRANSDUCTION IN BRAIN

严重的抑郁症可以通过慢性而非急性的， 抗抑郁药物和电惊厥发作的管理 （ECS）。虽然这些广泛使用的治疗的作用机制是 由于人们尚未清楚地了解，治疗效果的延迟导致了 神经元功能的某些适应性改变必然发生的假说 在治疗过程中。临床前和临床研究支持 去甲肾上腺素（NE）和5-羟色胺（5-HT） 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这种行为。这不是 令人惊讶的是，由于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 受体后适应、胞内位点适应和基因调控 表情我们的初步研究表明，慢性，但不是 急性，抗抑郁药的管理增加cAMP的水平， 颗粒级分中的依赖性蛋白激酶（PKA）酶活性， cAMP反应元件结合蛋白（CREB） 免疫反应性。我们还发现 抗抑郁治疗增加脑源性神经营养素水平 在额叶皮层和海马区， 海马，BDNF诱导被局部输注 CREB反义而非正义寡核苷酸，提供功能性的 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级联和增加BDNF表达。为了验证这个假设， 我们将确定不同类型的抗抑郁药 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，以及几种 非典型抗抑郁药对PKA和CREB水平及BDNF表达的影响 和trkB mRNA。相关性和重要性 这些后受体适应将通过几个标准来验证， 包括药理学特异性分析，通过 非抗抑郁精神药物治疗检查 （氟哌啶醇、可卡因、地西泮和吗啡），选择性剂量反应， 时间进程和区域特性。将通过标准品分析PKA 酶分析和蛋白质印迹分析，CREB免疫反应， 磷酸化和去磷酸化形式，将通过Western印迹法测定。 通过CRE凝胶位移分析确定CREB功能， BDNF和trkB mRNA将通过RNA酶保护，北方印迹， 和原位杂交。PKA-CREB级联的激活和 BDNF诱导可介导神经元的长期适应 对抗抑郁治疗的反应。

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.