The Effects of Caffeine and Nicotine on the Pulsation Rate of Lumbriculus variegatus

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Date: 3/10/2015

Introduction

Caffeine and nicotine are household drugs that have physiological consequences. Caffeine is a stimulant while nicotine is a depressant. One physiological consequence of the intake of caffeine or nicotine is the increase or decrease of pulsation rate. Pulsation, or heart rate, is the speed of the heartbeat measured by number of poundings of the heart per unit time. To test the effects of caffeine and nicotine, the organism Lumbriculus variegatus, or black worm, will be used. Black worms are an ideal organism for the measurement of heartbeats because they are translucent and substances can penetrate their skin easily (Fillafer 2013). We thought that if we increase the concentration of caffeine, then the pulsation rate of Lumbriculus variegatus will increase. Also, if we increase the concentration of nicotine, then the pulsation rate of Lumbriculus variegatus will decrease. Similarly, if we were to use extractions of these household drugs, we would achieve equal results. If we increase the concentration of tea and coffee, which both contain caffeine, then the pulsation rate of Lumbriculus variegatus will increase. However, if we were to increase the concentration of decaf, which contains no caffeine, we should see no difference in the pulsation rate of Lumbriculus variegatus. If we increase the concentration of chewing tobacco and cigar tobacco, which both contain nicotine, then the pulsation rate of Lumbriculus variegatus will decrease.

Our justification for the hypothesis that caffeine and its exacts will increase pulsation rate is because caffeine is a stimulant (Lesiuk 1999). This means that when taken, caffeine will increase metabolism, which requires an increased heart rate. Meanwhile, nicotine should decrease pulsation rate because it is a depressant (Lesiuk 1999). Thus, nicotine decreases metabolism and will require a lower heart rate.















Results

This experiment was done in two parts. The first, part 1, focuses on the drugs caffeine and nicotine. Part 2 focuses on the extracts, tea, coffee, decaf, chewing tobacco, cigar tobacco. A total of 6 Lumbriculus variegatus used for each treatment. These worms were labeled A-F.

Part 1 Table- Pulsation rates before and after subjecting black worms to 1 mM nicotine
Rate before
Treatment(#beats/min) Rate after
Treatment(#beats/min) Change in rate
(#beats/min)
Worm A 17.33 13.33 -4.00
Worm B 17.66 14 -3.66
Worm C 18.33 12.66 -5.67

Part 2 Table- the change in the mean pulsation rate of black worms subjected to caffeine and drug extractions.

Change in mean pulsation rate (# beats per minute
Tea Coffee Cigar tobacco Chewing Tobacco Decaf 1mM
Caffeine 10 mM
Caffeine Control .5 mM
nicotine
A 4.00 3.00 -3.00 2.00 0.67 21.70 3.67 -3.67 -6.33
B 2.30 3.30 -4.33 3.00 23.33 9.00 5.33 -1.00 -5.70
C 12.30 1.30 -3.00 0.30 2.34 14.70 4.66 1.33 -4.40
D 14.00 13.33 -5.34 1.33 3.00 0.64 3.30 .33 -11.00
E 15.67 12.00 -5.33 2.00 0.00 8.40 15.03 -1.33 -3.67
F 21.33 10.00 -6.00 4.00 4.00 3.34 1.00 -1.33 -3.67
To analyze our data, we graphed our change in pulsation rates and standard deviations for the class data.

Figure 1- Column graph of our part 1 and part 2 tables. The column graph shows the means of each treatment for all 6 sample worms as well as the standard deviations.