Mackowiak Bryan, Haggerty David L, Lehner Taylor, Lin Yu-Hong, Fu Yaojie, Lu Hongkun, Pawlosky Robert J, Ren Tianyi, Seo Wonhyo, Feng Dechun, Zhang Li, Lovinger David M, Gao Bin
Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
bioRxiv. 2025 Jan 13:2025.01.09.632203. doi: 10.1101/2025.01.09.632203.
Ethanol metabolism is intimately linked with the physiological and behavioral aspects of ethanol consumption. Ethanol is mainly oxidized by alcohol dehydrogenase (ADH) to acetaldehyde and further to acetate via aldehyde dehydrogenases (ALDHs). Understanding how ethanol and its metabolites work together to initiate and drive continued ethanol consumption is crucial for identifying interventions for alcohol use disorder (AUD). Therefore, the goal of our study was to determine how ADH1, which is mainly peripherally-expressed and metabolizes >90% of ingested ethanol, modulates ethanol metabolite distribution and downstream behaviors.
Ethanol consumption in drinking-in-the-dark (DID) and two-bottle choice (2BC) drinking paradigms, ethanol metabolite concentrations, and lickometry were assessed after ADH1 inhibition and/or in -knockout ( KO) mice.
We found that KO mice of both sexes exhibited decreased ethanol consumption and preference compared to wild-type (WT) mice in DID and 2BC. ADH1 inhibitor fomepizole (4-MP) also significantly decreased normal and sweetened ethanol consumption in DID studies. Measurement of ethanol and its metabolites revealed that ethanol was increased at 1h but not 15 min, peripheral acetaldehyde was slightly decreased at both time points, and ethanol-induced increases in acetate were abolished after ethanol administration in KO mice compared to controls. Similarly, ethanol accumulation as a function of consumption was 2-fold higher in KO or 4-MP treated mice compared to controls. We then used lickometry to determine how this perturbation in ethanol metabolism affects drinking microstructure. KO mice consume most of their ethanol in the first 30 min like WT mice but display altered temporal shifts in drinking behaviors and do not form normal bout structures, resulting in lower ethanol consumption.
Our study demonstrates that ADH1-mediated ethanol metabolism is a key determinant of ethanol consumption, highlighting a fundamental knowledge gap around how ethanol and its metabolites drive ethanol consumption.
乙醇代谢与乙醇摄入的生理和行为方面密切相关。乙醇主要通过乙醇脱氢酶（ADH）氧化为乙醛，并通过乙醛脱氢酶（ALDH）进一步氧化为乙酸盐。了解乙醇及其代谢产物如何共同作用以启动和推动持续的乙醇摄入，对于确定酒精使用障碍（AUD）的干预措施至关重要。因此，我们研究的目的是确定主要在周边表达且代谢超过90%摄入乙醇的ADH1如何调节乙醇代谢产物分布和下游行为。
在ADH1抑制和/或基因敲除（KO）小鼠中，评估黑暗中饮酒（DID）和双瓶选择（2BC）饮酒模式下乙醇的摄入量、乙醇代谢产物浓度以及舔舐行为测定。
我们发现，与野生型（WT）小鼠相比，两种性别的KO小鼠在DID和2BC实验中乙醇摄入量和偏好均降低。ADH1抑制剂4-甲基吡唑（4-MP）在DID研究中也显著降低了正常和加糖乙醇的摄入量。乙醇及其代谢产物的测量结果显示，乙醇在1小时时增加，但在15分钟时未增加，周边乙醛在两个时间点均略有下降，与对照组相比，乙醇给药后KO小鼠中乙醇诱导的乙酸盐增加被消除。同样，与对照组相比，KO或4-MP处理小鼠中乙醇积累与摄入量的函数关系高出2倍。然后，我们使用舔舐行为测定来确定乙醇代谢的这种扰动如何影响饮酒微观结构。KO小鼠像WT小鼠一样在最初30分钟内消耗大部分乙醇，但显示出饮酒行为的时间变化改变，且未形成正常的饮酒发作结构，导致乙醇摄入量降低。
我们的研究表明，ADH1介导的乙醇代谢是乙醇摄入的关键决定因素，凸显了围绕乙醇及其代谢产物如何驱动乙醇摄入的一个基本知识空白。
