COCAINE, HEROIN & OPIOID METABOLISM BY CARBOXYLESTERASES

本项目的总体目标是了解生物化学基础。 酶对可卡因失活的调节作用 对非活性代谢物的水解以及对其形成的调节 活性代谢物苯甲酰ecGonine乙酯或乙基可卡因，其 是由酒精和可卡因形成的。持续时间和刺激作用 可卡因的主要限制是它的水解率 苯甲酰ecGonine和ecGonine甲酯。这些主要代谢物是 热的药理活性作为精神运动兴奋剂。两种不同的 已在肝脏中发现了催化水解酶的酯酶 可卡因分别转化为苯甲酰ecGonine和ecGonine甲酯。这个 这一应用的研究将集中在这两种物质的提纯上。 柱层析分离酯酶及其性质的研究 分子性质，即。分子量、亚基结构和 部分氨基酸序列。底物和抑制剂的特异性 这些酶将通过稳态和停流动力学进行检测。 分析。 可卡因的一种活性代谢物乙基可卡因已在 同时饮酒和吸食可卡因的人。在大鼠肝脏和 大脑中，乙基可卡因浓度达到可卡因水平的18%-30% 在注射酒精和可卡因后。事实证明， 乙基可卡因在调节致命性方面比可卡因更有效，而且 可卡因和乙醇的共同滥用导致肝脏毒性增加，因为 而不是只吸可卡因。肝酯酶能将可卡因分解成 苯甲酰ecGonine还将催化可卡因的酯交换反应 乙醇存在下的乙基可卡因。乙基可卡因的动力学研究 队形由。将对纯化的酯酶进行检测。抗体将会是 制备纯化的可卡因酯酶和乙基转移酶，及其 将通过免疫印迹法检测其在人体组织中的分布。 酒精和可卡因共同滥用的原因和性质 这种药物组合与任何一种药物相比有哪些有益的效果 独自一人还不得而知。老鼠现在已经被证明是自我管理的。 乙基可卡因颅内注射至内侧前额叶皮质，类似于 可卡因。强化效果和潜在的滥用责任 将通过确定下列条件来评估乙基可卡因 大鼠将通过静脉和脑内自我注射乙基可卡因 与可卡因相比。乙醇对静脉注射可卡因的影响 自我管理也将被审查。这些研究应该提供 洞察这些药物联合使用的高发病率和 这种做法的潜在健康风险。

The overall goal of this project is to understand the biochemical basis for the regulation of the inactivation of cocaine by its enzyme-mediated hydrolysis to inactive metabolites, and the regulation of formation of the active metabolite benzoylecgonine ethyl ester or ethylcocaine, which is formed from alcohol and cocaine. The duration and stimulant effects of cocaine are limited principally by its rate of hydrolysis to benzoylecgonine and ecgonine methyl ester. These major metabolites are hot pharmacologically active as psychomotor stimulants. Two different esterases have been identified in liver that catalyze the hydrolysis of cocaine to benzoylecgonine and ecgonine methyl ester, respectively. The studies in this application will focus on the purification of these two esterases by column chromatography and the characterization of their molecular properties, viz. molecular weight, subunit structure and partial amino acid sequence. The substrate and inhibitor specificity of these enzymes will be examined by steady-state and stopped flow kinetic analysis. An active metabolite of cocaine, ethylcocaine, has been identified in individuals taking alcohol and cocaine concurrently. In rat liver and brain, the ethylcocaine concentration reaches 18-30% of the cocaine level after injection of alcohol and cocaine. It has been shown that ethylcocaine is more potent than cocaine in mediating lethality, and that coabuse of cocaine and ethanol leads to increased hepatotoxicity as compared to cocaine alone. The liver esterase that hydrolyzes cocaine to benzoylecgonine will also catalyze the transesterification of cocaine to ethylcocaine in the presence of ethanol. The kinetics of ethylcocaine formation by. the purified esterase will be examined. Antibodies will be prepared to purified cocaine esterases and ethyltransferases, and their distribution in human tissues will be examined by immunoblotting. The reasons for the common coabuse of alcohol and cocaine, and the nature of the rewarding effects of this combination of drugs versus either drug alone is not known. Rats have now been shown to self-administer ethylcocaine intracranially to the medial prefrontal cortex, similar to that of cocaine. The reinforcing effects and potential abuse liability of ethylcocaine will be assessed by determining conditions under which rats will intravenously and intracranially selfadminister ethylcocaine compared with cocaine. The effects of ethanol on intravenous cocaine self-administration will also be examined. These studies should provide insight into the high incidence of the combined use of these drugs and potential health risk of this practice.