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.

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:
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)


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 .


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)
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

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


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.


I believe that this lab helped me learn how to research and experiment
with scientific data more so than I did before. The results