Adrenaline or epinephrine, ready for action

Adrenaline or epinephrine, ready for action

Adrenaline, also called epinephrine, is a substance produced naturally by our body and that has various functions. It is a hormone, since it travels through the bloodstream and acts in organs away from the place where it is produced, with different effects throughout the body, and is also a neurotransmitter, that is, a substance released by neurons in synaptic spaces to communicate chemically with other neurons and cause a certain effect.


  • 1 What is the function of adrenaline?
  • 2 Adrenaline and stress
  • 3 Medical applications

What is the function of adrenaline?

Adrenaline is synthesized in the Kidney glands, which are small capsules located above the kidneys, and in some neurons of the central nervous system.

Adrenaline is the substance responsible for the fight or flight reaction, which allows us to prepare to face an attack, a danger or a threat to survival. Faced with a stress situation, the body quickly releases adrenaline into the blood, so that it sends impulses to different organs to respond to that situation.

Increase heart rate

When adrenaline is released in the heart, it begins to beat faster, and in this way more blood reaches the muscles to provide oxygen and nutrients necessary for the physical effort.

Increase breathing

Adrenaline causes a relaxation of the musculature of the respiratory tract, to allow an increase in the oxygen supply necessary to maintain a faster activity.

Increase glucose metabolism

The adrenaline hormone acts on the liver cells and muscles, causing an increase in glycogen metabolism, which is the way in which energy is stored. When the glycogen breaks down, glucose is generated, which will be available for provide extra fuel necessary to give an answer to the stress situation.

Dilata the pupils

When the pupils dilate, the vision becomes clearer and we are more aware of what is happening around us, and so we can see the danger better.

Stops bowel movement

By slowing the intestinal rhythm, it allows you to better distribute energy at times of action, to provide more energy wherever it is most needed.

Decrease pain

By acting on the mechanisms of pain, adrenaline or epinephrine allows us to flee or fight despite the possible harm we may suffer.

Psychological effects of adrenaline

One of the consequences of adrenaline discharge is that it allows us to be more attentive, with a higher level of both physical and intellectual or psychological hyperactivity. East euphoria state it is the one that reproduces when we practice extreme sports, for example, and can be addictive.

Adrenaline and stress

The response triggered by adrenaline has a special evolutionary sense, since it was especially important when man lived in the middle of nature and had to face multiple dangers that lurked. Today, this immediate, effective and rapid response to the environment does not make much sense, except on special occasions, such as a traffic accident, and is much more common than what causes us to increase adrenaline levels Be it an emotional stress, whether for work or personal reasons. In this case, it can produce dizziness, tachycardia and vision changes. In addition, releasing glucose in a situation where an extra supply of energy is not necessary, irritability and agitation occur. In situations of continued or chronic stress, it can occur insomnia, headaches, nausea, feeling restless and nervous and even heart damage.

How to regulate excess adrenaline

To regulate excess adrenaline release it is vital to reduce physical and emotional stress. For this, it is necessary to analyze the situations that stress us and try to find solutions that allow us to live better.

Medical applications

Adrenaline or epinephrine, in addition to occurring naturally in the body, also can be synthesized in the laboratory, and is used as a drug to treat different situations taking advantage of its mechanism of action.

Cardiorespiratory arrest

Epinephrine is used as a medicine to treat cardiac arrest, which can be caused by myocardial infarction, or some arrhythmias.


Thanks to its dilatory effect of the respiratory tract, epinephrine is used to treat severe allergic reactions that cause anaphylactic shock, as well as septicemia (serious blood infections).


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Carpenter, M.B. (1994). Neuroanatomy Fundamentals Buenos Aires: Panamerican Editorial.

From April, A .; Ambrose, E .; De Blas, M.R .; Caminero, A .; From Pablo, J.M. i Sandoval, E. (eds) (1999). Biological basis of behavior. Madrid: Sanz and Torres.