NOVEL NEUROSTEROIDS FOR ALCOHOL-RELATED CONDITIONS

酒精中毒和酒精滥用在美国和世界各地造成严重的健康问题。 大量的努力已经被导向开发疗法，但成功有限，复发是常见的。 即使在长期戒断后，戒断症状和/或强烈的渴望也常常促使复发。 因此，同时神经调节戒断症状和酒精寻求行为可能是治疗性的。 内源性神经活性类固醇，包括3 α-羟基-5 α-胆甾烷-20-酮（3 α，5 α-THP或epiallopregnanolone），对压力，焦虑，酒精和药物寻求行为有深远的影响。 一些证据表明，3 α，5 α-THP通过大脑区域中的GABA能机制参与这些行动，这些机制在酒精戒断、渴望和奖励的调节中很重要。我们实验室的初步结果表明，3 α，5 α-THP及其氨基类似物（NPI-113）刺激GABA受体介导的C1-摄取，防止荷包牡丹碱诱导的癫痫发作，并减少酒精偏好大鼠的饮酒。其他研究人员已经证明，3 α，5 α-THP可以减少焦虑和攻击性，这些症状可能会促进饮酒行为。 总的来说，这些观察结果表明，3 α，5 α-THP在调节与酒精寻求行为和戒断管理相关的大脑机制中起着至关重要的作用。 然而，由于代谢降解，这些天然存在的神经类固醇是超短效的（20-30分钟）。 该项目的目标是开发神经甾体药物开发模型，包括合成新化合物，体外和体内筛选，药代动力学和毒理学评价以及最有前途的化合物的初步临床试验。 我们最近测试了特定的氨基和氰基类似物的3 α，5 α-THP含有化学部分，阻止代谢位点。 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，并且在减少饮酒行为方面具有较长的作用持续时间（4-6小时）。 这些性质应该提供治疗益处，并且对于开发具有GABAA调节和抗渴望活性的新型药剂具有理论上的有用性。 具体地说，我们计划（1）利用我们以前研究中获得的结构信息合成3 α，5 α-THP的新型氨基和氰基类似物，（2）利用大鼠大脑皮层亚细胞突触神经体制备物中的C1-摄取测定在体外表征GABAA受体激动剂/拮抗剂活性，（3）在偏爱酒精的P和HAD大鼠中减少酒精消耗和在猴子中逆转酒精强化的试验，（4）在大鼠中逆转酒精戒断症状和癫痫发作的试验，（5）建立最具活性的类似物的毒性、耐受性和药代动力学特征，和（6）进行中试规模的双盲安慰剂对照临床试验，以确定最具活性的类似物在人类受试者的酒精寻求行为中的功效。 我们预测，这一全面的药物开发计划将建立一个综合的筛选系统，用于发现和开发治疗性神经类固醇，以管理问题饮酒和戒断。

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.