Effect of dopamine, caffeine and ethanol on the heart rate of Daphnia

Heart rates (beats per minute) was initially counted without any treatment (controls). Subsequently, changes in the heart rate was monitored after the addition of selected agents.

心率（单位：次/分钟）最初在未施加任何处理的对照组（controls）中进行计数。随后，在加入选定的试剂后，对心率的变化进行监测。