THE%20EFFECTS%20OF%20EPHEDRINE%20ON%20THE%20HEART%20RATE%20OF%20THE%20120%20HOUR%20EXPLANTED%20CHICK%20EMBRYO - PowerPoint PPT Presentation

Title: THE%20EFFECTS%20OF%20EPHEDRINE%20ON%20THE%20HEART%20RATE%20OF%20THE%20120%20HOUR%20EXPLANTED%20CHICK%20EMBRYO


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

• By
• Alana Gutierrez, Scott Radio,
• and Dr. Jacqueline McLaughlin

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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
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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.

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Norepinephrine
HO HO CH2-CH2-NH2 HO_o _at__at_,
I_ _at__at_ CH2-CH2-NH2 z_at_-I,

• 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.

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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

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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.

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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
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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
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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
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Embryos In Vivo Heart Rate
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Embryos In Vitro Heart Rate
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0.002 Solution
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0.02 Solution
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0.2 Solution
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Side Study- Embryo 1 with Alcohol Solution

• Embryo 1

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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
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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.

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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
lthttp//members.tripod.com/JPE_Sprotsscience/gt
Figure 7. Chick Embryo