Carbamathione, A Novel Disulfiram Metabolite for Cocaine Dependence

描述（由申请方提供）：双硫仑是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。这种影响与酒精使用无关。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，通过细胞色素P450系统代谢为许多化学中间体。抑制肝线粒体醛脱氢酶（ALDH 2），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，N二乙基氨基甲酰基）谷胱甘肽（氨基甲酰）。在体内，氨基甲酸乙酯对ALDH 2没有影响，但抑制脑匀浆突触膜中的谷氨酸结合。因此，双硫仑可能具有两种药理学作用，作为ALDH 2抑制剂的外周作用和对多巴胺能系统的中枢作用。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，作为调查卡巴氨酯作用机制的更广泛研究的基础。分析和药效学研究将是本申请的重点。已经开发了通过质谱法测定氨基甲酸乙酯的方法。本研究将开发质谱和荧光法测定DETC-MeSO，氨基甲酸乙酯，多巴胺，谷氨酸和GABA。在药效学研究中，将对大鼠进行手术准备，并将探针植入丘脑核和腔静脉中，以使用双探针技术同时测定脑透析液和DETC-MeSO和卡巴氨酰胺的血液浓度。大鼠将接受双硫仑、DETC-MeSO和氨基甲酸乙酯处理，并使用微透析技术确定脑透析液和血液中是否存在DETC-MeSO和氨基甲酸乙酯。同时测定脑内氨基甲酸乙酯、多巴胺、谷氨酸和γ-氨基丁酸。同时分析血液和大脑中的DETC-MeSO和氨基甲酸乙酯将提供关于氨基甲酸乙酯是在外周还是在大脑中形成的信息。在双硫仑和DETCMeSO给药后发现脑透析液中的卡巴氨肽将为未来研究卡巴氨肽在可卡因动物模型中的作用提供支持。本研究的意义在于，卡巴氨可作为一种药理学工具，更好地描述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，卡巴氨替尼可能是比双硫仑更好的治疗可卡因依赖的候选药物，因为卡巴氨替尼不依赖于细胞色素P450酶，因此可以提供比双硫仑更有效、特异和一致的治疗效果。

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.