The Effects of Caffeine On the 4Day Old Chicken Embryonic
Heart Rate
Mazin Albert
Introduction
Chicken Heart Development
 Heart forms from precardiac
mesodermal tubes
 4 distinct regions
 2 chambers

Chicken Heart Development
Figure 1- 33-Hour
Chick Embryo
Figure 2- 48-Hour
Chick Embryo
Figure 3- 72-Hour
Chick Embryo
http://www.lv.psu.edu/jxm57/chicklab/outline.html
Caffeine
The most commonly used
pharmacologic substance.
 Caffeine increases heart rate during
sleep (Bonnet, et. al. 2005)
 Caffeine increases blood pressure,
stroke volume, and cardiac output
(Hartley, et. al. 2004).

Why Does Caffeine Do This?
Caffeine blocks adenosine on the
surface of the heart causing higher
HR.
 Adenosine is an antiarrythmic agent.
 Caffeine also inhibits enzymes that
play a role in “turning off”
stimulatory signals.

Purpose

To determine the effects of various
concentrations of exogenously
added caffeine on the 4-day in vitro
chicken embryo heart.
Hypothesis

The effects of exogenously added
caffeine at various concentrations to
the in vitro 4-day chicken embryo
heart will greatly increase the heart
rate (bpm).
Figure 4- Chicken Embryo
Methods

Prepared a stock 2% caffeine
solution. Then serial diluted the
solution with chick saline to yield
concentrations of 0.02, 0.002,
0.0002.
Methods
Windowed a 4-day chick embryo
according to the methods of Cruz,
et. al., 1993.
 Determined the in vivo heart rate.
 Explanted the 4-day chick embryo
according to the methods of Cruz,
et. al., 1993.

http://www.lv.psu.edu/jxm57/biol240.htm
l#labsyl
Figure 5- Windowed Egg
Methods

Application of Caffeine
Administered 3 mL of each dilution to
the in vitro chick embryo using the
least concentration first.
 Determined the in vitro heart rate of
the chick embryo.
 Repeated these steps in the order of
increasing concentration.


Repeated these methods on at least
six embryos.
Control

The in vivo and in
vitro heart rates of
a 4-day chick
embryos before
caffeine is
exogenously
applied.
Figure 6- In Vitro Chicken
Embryo
Results
In Vivo Heart Rates (bpm)
180
Beats Per Minute
160
140
120
100
Trial 1
80
Trial 2
60
Trial 3
40
20
0
Embryo 1 Embryo 2 Embryo 3 Embryo 4 Embryo 5 Embryo 6 Embryo 7
Embryo Number
Average
Results
In Vitro Heart Rates w/o Caffeine
140
Beats Per Minute
120
100
80
Trial 1
60
Trial 2
40
Trial 3
20
0
Embryo 1 Embryo 2 Embryo 3 Embryo 4 Embryo 5 Embryo 6 Embryo 7
Embryo Number
Average
Results
In Vitro Heart Rates - .0002
200
180
Beats Per Minute
160
140
120
Trial 1
100
Trial 2
80
Trial 3
60
40
20
0
Embryo 1 Embryo 2 Embryo 3 Embryo 4 Embryo 5 Embryo 6 Embryo 7
Embryo Number
Average
Results
In Vitro Heart Rates - 0.002
160
Beats Per Minute
140
120
100
Trial 1
80
Trial 2
60
Trial 3
40
20
0
Embryo 1 Embryo 2 Embryo 3 Embryo 4 Embryo 5 Embryo 6 Embryo 7
Embryo Number
Average
Results
In Vitro Heart Rates - 0.02
180
Beats Per Minute
160
140
120
100
Trial 1
80
Trial 2
60
Trial 3
40
20
0
Embryo 1 Embryo 2 Embryo 3 Embryo 4 Embryo 5 Embryo 6 Embryo 7
Embryo Number
Average
Results
Average Heart Rate (bpm)
Beats Per Minute
140
120
100
80
60
40
20
0
Average
In Vivo
In Vitro w/o
Caffeine
In Vitro 0.0002
In Vitro 0.002
In Vitro - 0.02
124
82
106
89
62
Caffeine Concentration
Data Interpretation




In vivo heart rate is higher than the in
vitro heart rate.
5 out of 7 embryos had an increase in
heart rate between in vitro w/o solution
to in vitro with 0.0002.
3 out of 7 embryos had an increase in
heart rate between in vitro with 0.0002
and in vitro with 0.002.
Arrhythmias were noted, mostly
tachycardia and atrial flutter.
Conclusion
Data did not support the hypothesis.
 Although the initial concentration
caused an increase in heart rate,
higher concentrations of caffeine did
not always result in a higher heart
rate.
 Overall trend showed a decrease in
heart rate.

Siamese Twins
Figure 7- Siamese Twins Chick Embryo
Future Experiments

After applying caffeine, incubate
embryo, until it has fully developed
to see if there were any adverse
effects on the overall development
of the chicken.
Questions


Thank you for
listening to my
presentation.
Are there any
questions?
Figure 8- Caffeine
Molecule
References






“Adenosine”. 2006. Wikipedia Foundation Inc. 22 March 2006.
<http://en.wikipedia.org/wiki/Adenosine#Action_on_the_heart.>
Bonnet, Michael, Ph.D., Manuel Tancer, M.D., Thomas Uhde, M.D., Vikram
K. Yeragani, M.D. “Effects of caffeine on heart rate and QT variability
during sleep.” Depression and Anxiety. 2005. Vol. 22, Issue 3. pgs 150155.
Cruz, Y.P. 1993. Laboratory exercises in developmental biology.
Academic Press, San Diego, California, 241 pages. [ISBN 0-12-198390-0]
[book]
Hartley, Terry, Lovallo, Wiliam, Whitsett, Thomas. “Cardiovascular Effects
of Caffeine in Men and Women.” The American Journal of Cardiology.
2004. Vol. 93. pgs. 1022-1026.
Hebert, Terry. “Re: How, and why does caffeine affect the rate of a
daphnia’s heart rate?”. 1999. MadSci Network. 22 March 2006.
<http://www.madsci.org/posts/archives/jul99/931925101.Zo.r.html.>
McLaughlin, Jacqueline and McCain, Elizabeth. Development and
Physiological Aspects of the Chicken Embryonic Heart. 1996. 12 Feb.
2005. <http://www.lv.psu.edu/jxm57/chicklab/outline.html>