The project that I chose to research was the effect of Ibuprofen on the heart rate of the
daphnia. The reason that I chose to do this was because many people in society use over
the counter pain killers without really understanding any of the long term effects of
this medicine other than clearing their aches pains, and swelling. One of the leading
drugs on the market today is Ibuprofen which you may know as Motrin or Advil. Both drugs
are identical except for quantity and price, and even there it might be the same. The
organism I chose to work with is a crustacean called the Daphnia. Later in this report I
will attempt to explain the significance of that organism and why I chose to conduct
tests on it.
I then, with the information at my disposal, conjured a hypothesis which I would test.
Using the materials at hand I, to the best of my ability tested my hypothesis. In
conducting the tests I created graphs and tables of my work.
At the conclusion of my experiment I came up with an answer that was almost unpredictable
with the information that I was using. Although this was a crude experiment, I believe
that I did gain a lot from it.
Introduction
The drug that I chose, Ibuprofen, is an anti-inflammatory analgesic. It is propionic
acid that is white and powdery, and soluble in water, and organic solvents such as
ethanol and acetone. (1) Its structural formula is:
(CH3)2CHCH2 CH(CH3)COOH
Its role of action as a drug is not completely clear to the sciences, but that with time
will change. One thing we do know is that people who have allergies to Aspirin should
not take this medicine. (2)
As of now we know that it may play a role in prostaglandin synthesis inhibition. (1)
Prostaglandin are hormonal like substances that form in animal tissue from polly
unsaturated fatty-acids. (3) They do affect several body systems including the central
nervous, gastrointestinal, urinary, and endocrine systems. It has been shown to have
very minor effects on smooth muscle contraction and the clotting ability of blood which
we are concerned with.(4) Excesses of these substances may cause pain, inflammation, and
fever.
It is also an analgesic which is used to reduce or eliminate pain without causing a loss
of consciousness. (4) Another name for these substances which we all know of is a
painkiller.
A water flea or Daphnia, is a member of the subclass Brachiopod, in the order Cladocera.
They are found in the plankton of open water. (5) What I was concerned with the Daphnia
was the fact that they are transparent organisms. Observing their inner organs is done
with ease and what I mainly focused on was the heart.
The almost colorless blood of the Daphnia flows anteriorly from the heart to the
hemocoeland inner wall of the carpous where gaseous exchanges occur. In a non-oxygenated
environment the organisms appear to be orange due to the changing color of their
hemoglobin. (6)
Hypothesis
Although Ibuprofen has been shown to have a very slight effect on the heart rate of
human beings this occurrence was very rare and unlikely according to research done. (2)
I hypothesized that Ibuprofen would have absolutely no effect on the heart rate of the
daphnia .
Procedure
To go about testing the hypothesis I first obtained a control using ten Daphnia. I
counted their heart rates and averaged them all out to have a 246 beat per minute
heartbeat. Here is a chart of my control:
Heart-rate of Daphnia (Control)
TRIAL # I II III IV V
1 240 240 248 242 248
2 259 244 243 251 242
BEATS 3 243 237 241 235 251
4 253 246 241 248 243
5 242 247 247 252 249
PER 6 260 241 246 241 241
7 251 248 243 240 239
8 239 240 249 248 246
MINUTE 9 259 243 245 249 252
10 246 249 249 245 237
AVG. 249 243 245 245 247
OVERALL AVG. 246
After having gained a control from which I would base my experiment on I created
Ibuprofen solutions of varying concentrations using the water from the environment of the
Daphnia as to avoid creating another variable which might affect the heart rate. I
created the different concentrations by means of "Serial Dilution".
I did this progressively until I reached a 5% concentration. After having created the
dilution's I subjected 5 Daphnia to each solution and observed their heartbeats as shown
below:
Heart Rate with Ibuprofen Solutions...
CONCENTRATIONS 90% 45% 22% 11% 5%
1 240 240 248 242 248
2 259 244 243 251 242
BEATS 3 243 237 241 235 251
4 253 246 241 248 243
5 242 247 247 252 249
PER 6 260 241 246 241 241
7 251 248 243 240 239
8 239 240 249 248 246
MINUTE 9 259 243 245 249 252
10 246 249 249 245 237
TIME(MIN.) 7 9 13 18 23
SPONTANEOUS HEART-
RATE INCREASE ...
SPONTANEOUS HEART
FAILURE
Results
At first my results showed no change in the heart rate of the Daphnia. Within a certain
time, according to each solution, there was a spontaneous increase in heart rate and then
a spontaneous heart failure. This occurred in all solutions progressively from 90% in
7min. To 5% in 23min.
Discussion
I believe that this lab helped me learn how to research and experiment with scientific
data more so than I did before. The results negate my hypothesis yet I still believe
that they did not negate them 100%.
Conclusion
In conclusion the heart rate was effected by the Ibuprofen, however, I do not believe
this effect to be a direct effect on the heart, instead I believe that the Ibuprofen
indirectly effected it by causing something else to go wrong in the organism.
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