The Effects of Caffeine On the 4-Day Old Chicken Embryonic Heart Rate

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The Effects of Caffeine On the 4-Day Old Chicken
Embryonic Heart Rate

• Mazin Albert

2
Introduction

• Chicken Heart Development
• Heart forms from precardiac mesodermal tubes
• 4 distinct regions
• 2 chambers

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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
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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).

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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.

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Purpose

• To determine the effects of various
  concentrations of exogenously added caffeine on
  the 4-day in vitro chicken embryo heart.

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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
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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.

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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.htmllabsyl
Figure 5- Windowed Egg
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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.

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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
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Results
13
Results
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Results
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Results
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Results
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Results
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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.

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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.

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Siamese Twins
Figure 7- Siamese Twins Chick Embryo
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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.

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Questions

• Thank you for listening to my presentation.
• Are there any questions?

Figure 8- Caffeine Molecule
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References

• Adenosine. 2006. Wikipedia Foundation Inc. 22
  March 2006. lthttp//en.wikipedia.org/wiki/Adenosin
  eAction_on_the_heart.gt
• 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 150-155.
• 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 daphnias heart rate?.
  1999. MadSci Network. 22 March 2006.
  lthttp//www.madsci.org/posts/archives/jul99/931925
  101.Zo.r.html.gt
• McLaughlin, Jacqueline and McCain, Elizabeth.
  Development and Physiological Aspects of the
  Chicken Embryonic Heart. 1996. 12 Feb. 2005.
  lthttp//www.lv.psu.edu/jxm57/chicklab/outline.html
  gt