CHRONIC BENZODIAZEPINES--BEHAVIOR AND NEUROCHEMISTRY

苯二氮卓类药物是最常用的精神药物 在美国和国际上的药物。这些药物的临床应用 药物的发展受到耐受性和体能的限制 依赖。此外，有证据表明， 苯二氮类药物的滥用和依赖可能会导致这种滥用。这个 苯二氮类药物耐受和依赖的机制仍然存在 不确定。在本提案的前一阶段，我们制定了一个 苯二氮类药物耐受和戒断小鼠模型 描述了GABAA受体复合体的详细变化 这个型号。简而言之，苯二氮卓类激动剂的给药是 与行为耐受和受体下调有关； 停药与短暂性行为戒断有关 与受体上调相一致的综合征。慢性拮抗剂和 反向激动剂的应用也与受体有关 上调。慢性拮抗剂和反向激动剂给药 也与受体上调有关。此外，我们还有 建立了一种评估苯二氮卓类药物作用的体外系统 培养的皮质神经元。结果大体上与所获得的结果相似 在活体内。本提案是这些模式的延伸 在两个主要领域：1。分子生物学方法；和2。 限制耐受性和依赖性的药物干预。这个 最近克隆的多个GABAA受体亚基开启分子 耐受性和退缩的研究方法及模型 我们以前的研究中所描述的特征可以很容易地扩展到这些 方法：研究方法。事实上，我们的初步研究表明， 苯二氮类药物延长后几种GABAA受体亚单位的mRNA表达 行政管理。这一发现已经被另一个人证实 实验室，应该扩展到GABAA受体的其他亚单位。 此外，其他苯二氮卓类药物将在慢性疾病期间进行评估 管理和停用后，包括原地 应用杂交技术评估解剖定位和核游程 停止研究以评估对转录的影响。还有，抗体 受体亚基的特异性将被用来评估 亚基蛋白的表达，并将这些结果与mRNA进行关联 数据。第二个主要研究领域涉及药理学。 已提出的限制苯二氮类药物耐受性的干预措施 和依赖。我们开发的小鼠模型非常适合于 评估剂量递减、拮抗剂和抗惊厥药物的使用， 和部分激动剂治疗。拟议的研究将提供一个 慢性苯二氮卓类药物在分子水平的影响 以及对具有直接影响的干预措施的评价 与预防苯二氮类药物戒断的相关性。

Benzodiazepines are the most frequently prescribed psychotropic medications in the U.S. and internationally. Clinical use of these drugs is limited by the development of tolerance and physical dependence. In addition, there is evidence for substantial benzodiazepine abuse, and dependence may contribute to this abuse. The mechanisms underlying benzodiazepine tolerance and dependence remain uncertain. Over the prior phase of this proposal, we have developed a model of benzodiazepine tolerance and withdrawal in the mouse, and have characterized in detail alterations at the GABAA receptor complex in this model. In brief, benzodiazepine agonist administration is associated with behavioral tolerance and receptor downregulation; discontinuation is associated with a transient behavioral withdrawal syndrome coincident with receptor upregulation. Chronic antagonist and inverse agonist administration also are associated with receptor upregulation. Chronic antagonist and inverse agonist administration also are associated with receptor upregulation. In addition, we have developed an in vitro system to assess benzodiazepine effects on cultured cortical neurons. Results in general parallel those obtained in vivo. The present proposal represents an extension of these models in two major areas: 1. Molecular biological methods; and 2. Pharmacological interventions to limit tolerance and dependence. The recent cloning of numerous GABAA receptor subunits opens molecular approaches to studies of tolerance and withdrawal, and the models characterized in our prior studies can be readily extended to these methods. Indeed, our preliminary studies indicate striking decreases in mRNA for several GABAa receptor subunits after prolonged benzodiazepine administration. This finding, which has been confirmed by another laboratory, should be extended to other subunits of the GABAa receptor. In addition, other benzodiazepines will be evaluated during chronic administration and after discontinuation, including in situ hybridization techniques to assess anatomic localization and nuclear run off studies to evaluate effects on transcription. Also, antibodies specific for receptor subunits will be used to assess alterations in subunit protein expression, and to correlate these results with mRNA data. The second major area of study involves pharmacologic interventions which have been proposed to limit benzodiazepine tolerance and dependence. The mouse model we have developed is well-suited to assessing dose-tapering, antagonist and anticonvulsant administration, and partial agonist treatment. The proposed studies will provide a broad picture of effects of chronic benzodiazepines at the molecular level, together with evaluation of interventions that have direct relevance to prevention of benzodiazepine withdrawal.