Carbamathione A Novel Disulfiram Metabolite for Cocaine Dependence

描述（由申请人提供）：双硫仑是一种用于治疗酒精滥用的药物，已有50多年的历史，已被证明可以减少可卡因依赖患者的可卡因使用。这种影响与酒精的使用无关。双硫仑减少可卡因使用的机制尚不清楚。双硫仑是一种前药，由细胞色素P450系统代谢为许多化学中间体。抑制肝脏线粒体醛脱氢酶（ALDH2）是其用于酒精中毒治疗的药理学基础，是由于s -甲基N， N-二乙基硫代氨基甲酸酯亚砜（DETC-MeSO）。研究表明DETC-MeSO代谢为S-(N, Ndiethylcarbamoyl)谷胱甘肽（carbamathione）。在体内，卡马硫酮对ALDH2无影响，但抑制脑浆液突触膜上谷氨酸的结合。因此，双硫仑可能有两种药理作用，一种是作为ALDH2抑制剂的外周作用，另一种是对谷氨酸系统的中枢作用。在这项探索性和发展性研究拨款申请中，将进行一系列研究，以获得所需的初步数据，作为调查卡马硫酮作用机制的更广泛研究的基础。分析和药效学研究将是本应用的重点。质谱法测定卡马硫酮的方法已经建立。本研究将发展质谱法和荧光法测定DETC-MeSO、卡马硫酮、多巴胺、谷氨酸和GABA。在药理学研究中，将对大鼠进行手术准备，并将探针植入伏隔核和腔静脉，使用双探针技术同时测定DETC-MeSO和卡马硫酮的脑透析液和血液浓度。大鼠将接受双硫仑、DETC-MeSO和卡马硫酮治疗，并使用微透析技术确定DETC-MeSO和卡马硫酮是否可在脑透析液和血液中发现。同时测定脑卡马硫酮、多巴胺、谷氨酸和GABA的含量。同时对血液和大脑进行DETC-MeSO和卡马硫酮的分析将提供卡马硫酮是在外周还是在大脑中形成的信息。在双硫仑和DETCMeSO政府将后脑透析液中发现卡马硫酮，为进一步研究卡马硫酮对可卡因动物模型的影响提供了支持。本研究的意义在于，卡马硫酮可以作为一种药理学工具，更好地描述双硫仑对可卡因依赖的作用机制，并可能设计出更好、更具选择性的药物。在临床上，卡马硫酮可能是比双硫仑更好的治疗可卡因依赖的候选药物，因为卡马硫酮不依赖于细胞色素P450酶，因此可以提供比双硫仑更有效、更特异性和更一致的治疗效果。

DESCRIPTION (provided by applicant): Disulfiram, a drug used for the treatment of alcohol abuse for more than 50 years has been shown to reduce cocaine use in cocaine-dependent patients. This effect is independent of alcohol use. The mechanism by which disulfiram reduces cocaine use is unknown. Disulfiram is a prodrug and is metabolized by the cytochrome P450 system to a number of chemical intermediates. Inhibition of liver mitochondrial aldehyde dehydrogenase (ALDH2), the pharmacological basis for its use in alcoholism treatment, is due to S-methyl N, N-diethylthiolcarbamate sulfoxide (DETC-MeSO). Studies suggest that DETC-MeSO is metabolized to S-(N, Ndiethylcarbamoyl) glutathione (carbamathione). In vivo, carbamathione has no effect on ALDH2, but inhibits glutamate binding in synaptic membranes of brain homogenate. Thus, disulfiram may have two pharmacological effects, a peripheral action as an ALDH2 inhibitor and a central effect on the glutamatergic system. In this exploratory and developmental research grant application a series of studies will be carried out to obtain the preliminary data needed as the basis for more extensive studies investigating carbamathione's mechanism of action. Analytical and pharmacodynamic studies will be the focus of this application. Determination of carbamathione by mass spectrometry has already been developed. The present studies will develop the mass spectrometric and fluorometric methods for determining DETC-MeSO, carbamathione, and dopamine, glutamate, and GABA. In the pharmacodynamic studies, rats will be surgically prepared and a probe implanted into the nucleus accumbens and in the vena cava for determining brain dialysate and blood concentrations of DETC-MeSO and carbamathione simultaneously using a two-probe technique. Rats will be treated with disulfiram, DETC-MeSO, and carbamathione, and using microdialysis techniques, determine if DETC-MeSO and carbamathione can be found in brain dialysate and blood. The simultaneous determination of brain carbamathione, and dopamine, glutamate and GABA also will be carried out. Simultaneous analysis of blood and brain for DETC-MeSO and carbamathione would provide information as to whether carbamathione is formed peripherally or in the brain. Finding carbamathione in brain dialysate after disulfiram and DETCMeSO administration would provide support for future studies on the effect of carbamathione in a cocaine animal model. The significance of this research is that carbamathione can be used as a pharmacological tool to better delineate the mechanism of action of disulfiram in cocaine dependence and perhaps design better and more selective agents. Clinically, carbamathione may be a better drug candidate than disulfiram for treating cocaine dependence since carbamathione is not dependent upon the cytochrome P450 enzymes, and hence can provide a more potent, specific, and consistent therapeutic effect than disulfiram.