Nasty Nicotine: Recognizing the Fluctuating Effect Nicotine has on the Heart Rate of Daphnia magna Over Time

Abstract

Nicotine is a highly addictive drug that can influence the heart rate of those exposed to it by increasing the number of action potentials. Daphnia magna are comparable test models to that of humans to observe the drug’s cardiac effects, because they have myogenic hearts that are similar to that of a human’s heart. We believed that if the Daphnia magna was exposed to a nicotine solution over time, then the heart rate would peak at a certain time point before the parasympathetic nervous system would activate to decrease it. In this investigation, we observed the heart rate of Daphnia magna as it was submerged in a 10 nM nicotine solution for 20 minutes. For this experiment, we conducted five trials of measuring theDaphnia magna heart rate pre- and post- nicotine exposure every four minutes. Since nicotine is considered a stimulant in high doses, we thought it would peak at the 12-minute mark because the nicotine would be given enough time to influence action potential activation; however, our results showed that only three out of the five trials had the greatest heart rate at the 12-minute mark. After averaging our results at each time point, we found that the average line followed the general trend that heart rate increased until peaking at 12 minutes before gradually decreasing for the rest of the experiment.