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

The Effects of Caffeine On the 4-Day 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.

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

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  1. 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

  3. 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

  4. 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).

  5. 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.

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

  7. 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

  8. 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.

  9. 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.html#labsyl Figure 5- Windowed Egg

  10. 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.

  11. 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

  12. Results

  13. Results

  14. Results

  15. Results

  16. Results

  17. Results

  18. 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.

  19. 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.

  20. Siamese Twins Figure 7- Siamese Twins Chick Embryo

  21. 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.

  22. Questions • Thank you for listening to my presentation. • Are there any questions? Figure 8- Caffeine Molecule

  23. 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 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 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>

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