Mittelstadt S W, Hemenway C L, Craig M P, Hove J R
Abbott Laboratories, Dept. R46R, Abbott Park, IL 60064, United States.
J Pharmacol Toxicol Methods. 2008 Mar-Apr;57(2):100-5. doi: 10.1016/j.vascn.2007.10.004. Epub 2007 Dec 23.
It has been proposed that the analysis of heart rate in zebrafish embryos can be used to assess the potential effects of compounds on hERG. The purpose of this study was to investigate the effect of compounds on the heart rate and atrioventricular dissociation in zebrafish. The compounds investigated were chosen based on the association or lack of association with QTc prolongation in the clinic.
Three-day-old embryos were incubated in buffered embryo medium. On the day of the study, fish were placed in a petri dish containing 5.0 mL of embryo medium and 125 mg/L MS-222 anesthetic. Drugs to be tested were added to the medium from a stock solution to achieve the desired target concentration. Ten fish were incubated in each concentration of drug for 80 min. Beat rates of the atrium and ventricle were recorded after the incubation by counting beats of the respective chambers using standard brightfield stereomicroscopy.
All of the compounds associated with QT prolongation induced dissociation between the atrium and ventricular rates except D,L-sotalol and procainamide. The concentrations that induced dissociation tended to be higher than the hERG IC50. None of the negative control compounds caused atrioventricular dissociation at clinically efficacious concentrations.
In conclusion, the present data demonstrate that zebrafish can be utilized to assess the effects of chemicals on hERG. However, the practical use of this assay may be difficult because of the high concentrations that must be reached to see those pharmacological effects.
有人提出，对斑马鱼胚胎心率的分析可用于评估化合物对人乙醚 - 去极化相关基因（hERG）的潜在影响。本研究的目的是调查化合物对斑马鱼心率和房室分离的影响。所研究的化合物是根据其在临床中与QTc延长的相关性或缺乏相关性来选择的。
将3天大的胚胎置于缓冲胚胎培养基中培养。在研究当天，将鱼放入含有5.0 mL胚胎培养基和125 mg/L MS - 222麻醉剂的培养皿中。将待测药物从储备溶液加入培养基中以达到所需的目标浓度。每种药物浓度下孵育10条鱼，共80分钟。孵育后，通过使用标准明场立体显微镜计数各个腔室的搏动来记录心房和心室的搏动率。
除了D，L - 索他洛尔和普鲁卡因酰胺外，所有与QT延长相关的化合物均诱导心房和心室率之间的分离。诱导分离的浓度往往高于hERG IC50。在临床有效浓度下，阴性对照化合物均未引起房室分离。
总之，目前的数据表明斑马鱼可用于评估化学物质对hERG的影响。然而，由于必须达到较高浓度才能观察到这些药理作用，该检测方法的实际应用可能会很困难。
