Epinephrine

Epinephrine

Epinephrine, also known as adrenaline, is a potent hormone and neurotransmitter produced primarily by the adrenal glands. It plays a crucial role in the body's acute stress response, commonly referred to as the "fight or flight" reaction. Epinephrine prepares the body to confront or flee from perceived threats by increasing heart rate, dilating airways, and mobilizing energy stores.

Overview

Structural formula of Epinephrine.

Epinephrine is synthesized in the medulla of the adrenal glands from the amino acid tyrosine. Its release is stimulated by various factors, including stress, fear, exercise, and low blood glucose levels. Once in the bloodstream, epinephrine binds to adrenergic receptors on target cells, initiating a series of physiological changes designed to enhance the body's ability to respond to a crisis.

Production and Secretion

Production of epinephrine begins with the amino acid tyrosine, which is converted through several steps into dopamine and then further converted into norepinephrine. Within the adrenal medulla, norepinephrine is converted into epinephrine. The release of epinephrine into the bloodstream is controlled by the sympathetic nervous system, responding rapidly to stress signals.

Mechanism of Action

Upon release, epinephrine binds to alpha and beta-adrenergic receptors throughout the body, leading to:

• Increased heart rate and force of heart contractions
• Dilation of airways to improve oxygen intake
• Breakdown of glycogen to glucose in the liver for increased energy availability
• Redistribution of blood flow from non-essential to essential organs during acute stress

Clinical Uses

Epinephrine has several important clinical applications, including:

• Treatment of anaphylaxis, a severe allergic reaction, through the administration of epinephrine auto-injectors (e.g., EpiPen)
• As a medication to prolong the effects of local anesthetics
• Management of cardiac arrest to stimulate heart activity

Significance

Understanding the role and function of epinephrine is crucial for medical and physiological research. It is a key hormone in managing the body's response to stress and has significant implications for treating various conditions, including life-threatening allergic reactions and heart conditions.

See Also

• Adrenal glands
• Stress response
• Anaphylaxis
• Cardiac arrest

References

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External Links

• [Placeholder for link to detailed information on Epinephrine from the National Institutes of Health]
• [Placeholder for link to an article on the clinical uses of Epinephrine]

Other names

Also called adrenaline

Epinephrine Resources
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