THE EFFECTS OF EPHEDRINE ON THE HEART RATE OF THE 120 HOUR EXPLANTED CHICK EMBRYO

1. THE EFFECTS OF EPHEDRINE ON THE HEART RATE OF THE 120 HOUR EXPLANTED CHICK EMBRYO By: Alana Gutierrez, Scott Radio, and Dr. Jacqueline McLaughlin

2. The Electrical and Mechanical Sequence of a Heartbeat • Controlled by the sinoatrial node, or the pacemaker of the heart. In the chicken heart the cardiac rhythm is kept by the sinus venoeous. • Sets the rate and timing of the heart through electrical impulses. • Change in the rate and output of the heart is affected by the changes in the autonomic nervous system. Figure 1. The Human Heart

3. Ephedrine • Alkaloid extract from the Ma Haung plant which is a smooth muscle dilator used as a treatment for respiratory disorders such as asthma and bronchitis. • Used as an herbal dietary supplement due to its thermogenic qualities, which increases caloric expenditure to promote weight loss. • Figure 2. Chemical make-up of Ephedrine alkaloid.

4. HO HO CH2-CH2-NH2 HO_o :@@, I_ @@ CH2-CH2-NH2 z@-I, Norepinephrine • Is a biogenic amine, a neurotransmitter of the sympathetic nervous system produced from the amino acid tyrosine, and commonly known as noradreline • Is an amplifier of the sympathic nervous system that effectuates the “fight or flight” response of the body. • Often affect processes within the postsynaptic cell by binding to receptors on their membranes which, in turn, affects the activities of specific enzymes of the effector cell. • Causes widespread vasoconstriction of blood vessels which results in increased arterial blood pressure • Binding to Alpha1 receptors, it effectively increases the amount of free calcium, which leads increased heart rate and cardiac muscle contraction.

5. How Ephedrine Works • A stimulant that acts on the sympathetic nervous system via the phrenic nerve. It induces pre-synaptic terminals norepinephrine (noradrenaline-NA) into the synaptic space. • Secondary effect of increasing circulating adrenaline throughout the body. • Binds directly to beta-receptors, in place of norepinephrine, on the surface of adipocytes. • Results in the increased production of cyclic AMP within the effector cell. • Figure 3. Effects of ephedrine in the production of cyclic AMP

6. How Ephedrine Works • The increase in cyclic AMP increases the inflow of calcium into the cardiac muscle cells. • The calcium influx leads to an increase in heart rate and in cardiac muscle contraction. • The vasodilatation of coronary arteries results in increased cardiac blood flow as well.

7. Purpose • To study the effects of various ephedrine solutions on the heart rate (bpm) of the 120-hour chicken heart in vitro. • Furthermore, to investigate any heart irregularities which may occur following the exposure of ephedrine to the 120- hour chicken heart in vitro. Figure 4 56-hour Chick Embryo

8. Methods • Three ephedrine solutions in chick saline were prepared from a 20% ephedrine stock, with concentrations of 0.002%, 0.02%, and 0.2%. • An egg of 120-hours was obtained from an incubator and placed into a cotton filled glass beaker at the lab station. • The egg shell was then cut with a scissors to produce a “window” which was used to both visualize and explant the 120-hour chick embryo according to the methods of Cruz (1995). • An in vivo heart rate was taken immediately and repeated five times, in order to establish a control for the remainder of the experiment. Figure 5 Explanting the heart

9. Methods continued… • Following the methods of Cruz (1993), the embryo was then explanted from the shell and placed into a chick saline solution. • A paper doughnut is used to frame the embryo and the membranes encasing the border of the doughnut are excised. • The embryo is then removed from its shell and placed into a Syracuse dish that contains a warmed chick saline solution. • The gooseneck lamp is used to heat embryo to a temperature that is close to being in the incubator. • The ephedrine concentration being tested, 0.002% is placed into the Syracuse dish containing the embryo via a pipette and the effects of this solution are recorded. Figure 6 Donut Method Figure 7 Embryo In Vitro

10. Embryo’s In Vivo Heart Rate

11. Embryo’s In Vitro Heart Rate

12. 0.002% Solution

13. 0.02% Solution

14. 0.2% Solution

15. Side Study- Embryo 1 with Alcohol Solution • Embryo 1

16. Overview Data Interpretation • The heart rate of the chick embryo is indeed stimulated when the ephedrine concentration is added. • The experiment supported the hypothesis that this increase will lead to observed heart irregularities, such as arrhythmia's, which ultimately lead to cardiac arrest. Figure 6. Chick Embryo

17. Conclusion • The heart irregularities that were observed lead us to believe that ephedrine is not a satisfactory option for those looking for a dietary supplement. While it has been effective in treating those with respiratory disorders, it must be medically regulated to ensure its safe use.

18. References Cruz, Y.P. 1993. Laboratory Exercises In Development Biology. Academic Press, San Diego, California, 241 pages. Colker, C.I., et al. Journal of American College Nutrition. Pages 16(5): al 16, 1997. Davis, Ronald M., MD. “AMA Assists in Effort to Ban Ephedra.” February 21, 2003. McLaughlin, Jacqueline and Elizabeth McCain (1991). “Development and Physiological Aspects of the Chicken Embryonic Heart.” Campbell, Neil and Jane Reese (2002). Biology. Benjamin/Cummings: CA. Sixth Ed. Prevost, M. (2003). “Ephedrine, Caffeine, and Aspirin” <http://members.tripod.com/JPE_Sprotsscience/> Figure 7. Chick Embryo