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Biology of Drugs

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Biology of Drugs Powered By Docstoc
					Amanda Plaksin

Drunken Daphnia:

The Effects of Aspirin and Alcohol on the Nervous System and Heart Rate

Introduction: Imagine that you are a normal person, going about your daily routine. All of a sudden, you begin to develop a splitting headache. Your first reaction to this is pain, and your second reaction is to find relief for the pain; you reach for your aspirin. Then, while reading on the back of the bottle the proper dosage, a few bolded words catch your eye: ‘DO NOT TAKE WITH ALCOHOL’. A few questions pop into your head, which is still throbbing painfully; why? What affect would taking both alcohol and aspirin at the same time have on your body? It does not say on the bottle, so you shrug it off, take two aspirins with some water, and shortly continue on your daily routine, pain-free. Well, those questions you asked are the same ones that we did. Instead of shrugging it off, though, we wanted to find out just what would happen to a person’s nervous system and heart rate by testing the effects of the two drugs on a small crustacean named Daphnia. Since most drugs affect the nervous system of animals the same way they do humans, we know that heart rate is a reliable measure of a change in nerve activity.

Hypothesis: If aspirin and alcohol are taken together, then Daphnia in a combined aspirin/alcohol solution will have average heart rates lower than the Control, and lower than either Daphnia in alcohol alone or aspirin alone. Alcohol is a depressant, reducing the effect of glutamate which stimulates the heart. Aspirin is also a depressant and pain killer. The combination of both should have a double effect on the Daphnia’s heart rate. If Daphnia in a combined aspirin/alcohol solution had an average heart rate that was faster or similar to the Control and more like that of Daphnia in alcohol alone or aspirin alone, then our hypothesis would be refuted.

Materials: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Daphnia Petroleum jelly (Vaseline) Microscope slides Small rubber washers Cover slips Compound microscope Clock with second hand Medicine dropper for collecting Daphnia Ringer’s Solution 5ml medicine cup Data table Alcohol Solution Aspirin Solution (aspirin dissolved in water)

Procedure: A. Setup 1. Create a place to observe the Daphnia by rubbing a small amount of Vaseline onto one of the flat sides of a rubber washer. Place the washer, Vaseline side down onto a glass microscope slide. Press down, and then add 2 drops of Ringer’s Solution into the center of the rubber washer. 2. Collect one Daphnia from the stock culture using a medicine dropper. It may be difficult at first, but keep trying. 3. Once a Daphnia is in your dropper, wait until the Daphnia swims to the bottom, and then squeeze the dropper so that the Daphnia falls into the chamber. 4. Add a cover slip. 5. Place the slide on the microscope, turn it on, and observe under low power to avoid cooking the Daphnia. 6. Add a few drops of Ringer’s Solution to the 5ml medicine cup, and place it near the microscope. B. Collecting Control Data 1. Count the Daphnia’s heart beats for 10 seconds. Record this number under Trial 1 on your data table. 2. Turn off the microscope light and wait 20 seconds. 3. Record the counts for Trials 2 and 3. 4. Make notes of the Daphnia’s activity. 5. When finished, use the dropper to suck up the daphnia from the observation chamber and transfer it into the 5ml medicine cup full of Ringer’s Solution. Keep the Daphnia in the solution for 2 minutes and then transfer it back into the stock culture.

C. Testing With Aspirin and Alcohol 1. Repeat the setup steps. 2. Add one drop of aspirin solution to the chamber. Wait for 1 minute, then observe the Daphnia for a second minute and record its behaviors. 3. Collect the heart rate data like you did in steps 1-3 for Part B. 4. When finished, repeat step 5 of Part B. 5. Clean the slide and rubber washer with soap and water thoroughly. 6. Prepare your alcohol chamber by repeating the setup steps and adding one drop of alcohol solution to the chamber. 7. Repeat steps 3-5 in Part C. Record all data on the data table.

Results and Analysis: 10-Second HR 3 Trials Calculations Avg. 10 Sec Avg. 60 Sec Change HR HR In Heart Rate 31.6 189.6 N/A % Difference Observed in Behavior Heart Rate Swimming N/A around, calm Swimming in 73.73% circles, frantic, spazzing Sat there, 37.97% not moving, twitching every once in a while Stopped 179.1% moving. Heart beat racing, hard to count

Solution

Control

Aspirin

Trial 1: 30 Trial 2: 34 Trial 3: 31 Trial 1: 24 Trial 2: 24 Trial 3: 22 Trial 1: 15 Trial 2: 12 Trial 3: 9

23.3

139.8

49.8

Alcohol

12

72

117.6

Aspirin and Alcohol

Trial 1: Trial 2: Trial 3:

56.6

339.6

150

Heart Beats

400 350 300 250 200 150 100 50 0

Average 60 Second Heart Rate

Control

Aspirin

Alcohol Aspirin and Alcohol

This graph shows the increase in average heart beats per 60 seconds for Control, Aspirin, Alcohol, and Aspirin/Alcohol tests on Daphnia. It displays the decline from the Control, and then the skyrocketing jump of the Daphnia’s heart beats once aspirin and alcohol were combined.

Conclusion: Our hypothesis was that if aspirin and alcohol are taken together, then Daphnia in a combined aspirin/alcohol solution will have average heart rates lower than the Control, and lower than either Daphnia in alcohol alone or aspirin alone. Though, based on the data we collected, we must conclude that our hypothesis was refuted. This is because the Daphnia’s Aspirin/Alcohol average heart rate was much faster than the Control, Aspirin, and Alcohol heart rates, at a difference of 179.1%. When doing this experiment, we expected the Daphnia to die once we combined alcohol and aspirin in its chamber due to the fact that both drugs are depressants and reduce nervous system activity, therefore reducing heart rate. We thought that the combination would have a deadly effect on the small Daphnia, even though we knew it wouldn’t necessarily have the same killing effect on humans. Our curious results lead us to more questions, because we cannot come up with a direct answer as to why taking alcohol with aspirin would speed up the heart. Also, it makes us ask what exactly would happen to a human if both were taken at the same time. If more time was given, we could go back and retime our trials, paying more attention to the Daphnia’s behavior and first reaction to the drug to try and get an even better idea of how the drugs work on the nervous system. Also, it’s interesting to see how wild Daphnia would compare to the lab-raised Daphnia we used in our tests. Perhaps living in wild rivers and lakes would make them more susceptible to different things like chemicals and dirt, and therefore in testing make them less vulnerable to a drug’s effects because they are already used to other things being around them. Although it would be interesting to work more with the Daphnia, the idea and point of this experiment truly stemmed from your headache and the unexplained warning label on the back of the bottle.


				
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posted:11/10/2009
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