Daphnia Magna Experiment

Introduction

The use of model organisms in pre clinical trial is relied upon for the collection of safety and efficacy data prior to first in human clinical studies. The crustacean Daphnia magna is one model organism, whose heart rate is reported to react similarly to the human heart rate, when exposed to identical compounds (3).

In human studies, caffeine and nicotine have been reported to increase the heart rate of human beings (2).

The purpose of this study is to determine the effect of varying concentration of alcohol, caffeine and nicotine on the heart rate of a daphnia magna and confirm any similarities between the affect of the chemical compound on the heart rate of daphnia magna and human beings.

Material and Method

The crustacean Daphnia magna, maintained in water at room temperature, was obtained. The chemical compound used are five (5) fold dilution of one (1) molar aqueous nicotine, five (5) fold dilution of one (1) molar aqueous caffeine, 10 fold dilution of one (1) molar aqueous nicotine, five (5) fold dilution of one (1) molar aqueous caffeine, water and 100% alcohol.

Daphnia magna was collected via pipette and placed on a petri dish for viewing under the microscope.

The heartbeat per minute was calculated after exposure of Daphnia magna to one of the five chemical compounds listed above.

A total of twelve Daphnia magna were used for this experiment; two Daphnia magna were exposed simultaneously to each of the five chemical

compounds.

Result
The compounds diluted by five (5) folds of aqueous solution caused an average of 126.65% increase in heart rate while the compounds diluted by ten (10) folds aqueous solution caused an average of 80% increase in heart rate. Alcohol decreases the heart rate of the daphnia magna by 73%.

Table 1: Heart beats per minute of Daphnia magna after exposure to chemical compound
Chemical Compound Concentration n(sample size) Beats Per Minute Percentage Change
Nicotine 5 Fold Dilution 2 350 133.3
Caffeine 5 Fold Dilution 2 330 120
Caffeine 10 Fold Dilution 2 300 100
Nicotine 10 Fold Dilution 2 240 60
Water (Control/Baseline) Pure 2 150 0
Alcohol Pure 2 40 -73

Figure 1: Graph showing the effect of chemical compounds on the heart beat of the Daphnia magna
Conclusion and Discussion
Per the results, caffeine and nicotine have identical effects on the heart rate of Daphnia magna (Table 1). The percentage change of heart rate across all compounds is dependent on the dose strength (2).

Heart rate of human beings behaves similarly when exposed to the chemical compounds; the human heart rate increases after exposure to caffeine (1) and to nicotine (2).

Pre-clinical research with organism such as Daphnia magna can be used to obtain preliminary information on how a chemical compound can affect the cardiovascular nature of human beings (3). This information is important prior to the start of a phase I clinical trial; it can also be crucial in the labeling of the potential drug.