NOVEL NEUROSTEROIDS FOR ALCOHOL-RELATED CONDITIONS

酗酒和酗酒在美国和世界各地都造成了严重的健康问题。人们花了大量的精力来开发治疗方法，但成功有限，复发也很常见。戒断症状和/或强烈的渴望往往会导致复发，即使在长期戒断之后也是如此。因此，同时对戒断症状和寻酒行为进行神经调节可能是有疗效的。内源性神经活性类固醇，包括3α-羟基-5α-孕激素-20-酮(3α，5α-THP或表烯丙孕酮)，对应激、焦虑、酒精和药物寻找行为有深远的影响。几条证据表明，3Alpha，5Alpha-THP通过大脑区域的GABA能机制参与这些活动，这些区域在酒精戒断、渴望和奖励的调节中起重要作用。我们实验室的初步结果表明，3α，5αTHP及其氨基类似物(NPI-113)可刺激GABA受体介导的C1摄取，对荷包牡丹碱诱导的癫痫发作具有保护作用，并可减少酒精偏爱大鼠的饮酒。其他研究人员已经证明，3Alpha，5Alpha-THP可以减少焦虑和攻击性，这些症状可能会促进饮酒行为。总而言之，这些观察表明，3Alpha，5Alpha-THP在大脑机制的调节中发挥了关键作用，这些机制与酒精寻求行为和戒断的管理相关。然而，这些自然产生的神经类固醇是超短效的(20-30分钟)，因为代谢降解。该项目的目标是开发一种神经类固醇药物开发模型，包括新化合物的合成、体外和体内筛选、药代动力学和毒理学评价，以及最有希望的化合物的试点临床试验。我们最近测试了3α，5α-THP的特定氨基和氰基类似物，其中含有阻断代谢部位的化学部分。这些化合物具有调节GABAA受体介导的C1-通量的部分激动剂活性，并在减少饮酒行为方面具有更长的作用时间(4-6小时)。这些性质将为开发具有GABAA调节和抗渴求活性的新型药物提供治疗益处和理论上的有用。具体地说，我们计划(1)利用我们以前的研究中获得的结构信息合成新的氨基和氰基类似物3α，5α-THP，(2)利用大鼠大脑皮层亚细胞突触神经元的C1摄取实验来表征GABAA受体激动剂/拮抗剂的体外活性，(3)降低P和HAD大鼠的酒精消耗量和逆转猴子的酒精强化，(4)逆转大鼠的酒精戒断症状和癫痫发作，(5)建立最有效的类似物的毒性、耐受性和药代动力学曲线，以及(6)进行一项中试规模的双盲安慰剂对照临床试验，以确定最活跃的类似物在人类受试者寻求酒精行为中的有效性。我们预测，这一全面的药物开发计划将为发现和开发治疗饮酒和戒酒问题的治疗神经类固醇建立一个综合的筛查系统。

Alcoholism and alcohol abuse pose serious health problems in the United States and around the world. A great deal of effort has been directed toward developing therapies, but success has been limited and relapse is common. Relapse is often precipitated by withdrawal symptoms and/or intense craving, even after prolonged abstinence. Therefore, simultaneous neuromodulation of withdrawal symptoms and alcohol seeking behavior could be therapeutic. The endogenous neuroactive steroids, including 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha,5alpha-THP or epiallopregnanolone), have profound effects on stress, anxiety, alcohol and drug seeking behavior. Several lines of evidence suggest that 3alpha,5alpha-THP participates in these actions through GABAergic mechanisms in brain areas that are important in the regulation of alcohol withdrawal, craving and reward. Preliminary results from our laboratories demonstrate that 3alpha, 5alpha-THP and its amino-analog (NPI-113) stimulate GABA receptor-mediated C1- uptake, protect against bicuculline-induced seizures and reduce alcohol drinking in alcohol preferring rats. Other researchers have demonstrated that 3alpha,5alpha-THP reduces anxiety and aggression, symptoms that may promote alcohol-drinking behavior. Collectively, these observations suggest a crucial role for 3alpha,5alpha-THP in the regulation of brain mechanisms that are relevant to the management of alcohol-seeking behavior and withdrawal. However, these naturally occurring neurosteroids are ultra short acting (20-30 minutes) because of metabolic degradation. The objective of this project is to develop a model for neurosteroid medication development that includes synthesis of novel compounds, in vitro and in vivo screening, pharmacokinetic and toxicological evaluation and a pilot clinical trial of the most promising compound. We have recently tested specific amino- and cyano-analogs of 3alpha,5alpha-THP containing chemical moieties that block metabolic sites. These compounds have partial agonist activity modulating GABAA receptor-mediated C1- flux and a longer duration of action (4-6 hrs) in the reduction of alcohol drinking behavior. These properties should provide therapeutic benefits and have theoretical usefulness for development of novel agents with GABAA modulating and anti-craving activity. Specifically, we plan to (1) synthesize novel amino- and cyano-analogs of 3alpha,5alpha-THP using structural information derived from our previous studies, (2) characterize GABAA receptor agonist/antagonist activities in vitro using a C1- uptake assay in subcellular synaptoneurosome preparations from rat cerebral cortices, (3) test for reduction of alcohol consumption in alcohol preferring P and HAD rats and reversal of alcohol reinforcement in monkeys, (4) test for reversal of alcohol withdrawal symptoms and seizures in rats, (5) establish toxicity, tolerance, and pharmacokinetic profiles of the most active analogs, and (6) conduct a pilot scale double-blind placebo- controlled clinical trial to determine the efficacy of the most active analog in alcohol-seeking behavior in human subjects. We predict that this comprehensive medication development program will establish an integrated screening system for the discovery and development of therapeutic neurosteroids for the management of problem alcohol drinking and withdrawal.