Carbamathione A Novel Disulfiram Metabolite for Cocaine Dependence

描述(申请人提供)：双硫兰，一种用于治疗酒精滥用超过50年的药物，已被证明可减少可卡因依赖患者的可卡因使用。这种影响与饮酒无关。双硫兰减少可卡因使用的机制尚不清楚。双硫兰是一种前体药物，由细胞色素P450系统代谢成一些化学中间体。肝线粒体醛脱氢酶的抑制是其治疗酒精中毒的药理学基础，其抑制作用是由于S-N，N-二乙基硫代氨基甲酸亚砜(DETC-MESO)所致。研究表明，DETC-Meso被代谢为S-(N，N-二乙基氨基甲酰基)谷胱甘肽(氨基甲硫酮)。在体内，氨甲硫酮对ALDH2没有影响，但抑制了脑匀浆突触膜上谷氨酸的结合。因此，双硫兰可能有两种药理作用，一种是作为ALDH2抑制剂的外周作用，另一种是对谷氨酸能系统的中枢作用。在这项探索性和发展性研究补助金申请中，将进行一系列研究，以获得所需的初步数据，为更广泛地研究氨基甲硫酮的作用机制奠定基础。分析和药效学研究将是这一应用的重点。已建立了用质谱仪测定氨基硫酮的方法。本研究将开发测定DETC-Meso、氨基甲硫酮、多巴胺、谷氨酸和GABA的质谱学和荧光法。在药效学研究中，将通过手术准备大鼠，并将探针植入伏隔核和下腔静脉，使用双探针技术同时测定脑透析液和DETC-Meso和氨甲硫酮的血液浓度。大鼠将接受二硫仑、DETC-Meso和氨甲硫酮的治疗，并使用微透析技术，确定在脑透析液和血液中是否可以发现DETC-Meso和氨甲硫酮。同时还将进行脑氨甲硫酮、多巴胺、谷氨酸和GABA的测定。同时分析血液和大脑中的DETC-Meso和氨甲硫酮将提供氨甲硫酮是在外周还是在大脑中形成的信息。在双硫兰和DETCMeSO给药后，在脑透析液中发现氨甲硫酮，将为未来在可卡因动物模型中研究氨甲硫酮的效果提供支持。本研究的意义在于，氨甲硫酮可以作为一种药理工具，更好地阐明双硫仑在可卡因依赖中的作用机制，并可能设计出更好、更具选择性的药物。在临床上，氨甲硫酮可能是治疗可卡因依赖的更好的候选药物，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兰更有效、更特异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.