Adrenalin or Epinephrine: A Useful Guide with Questions and Answers

Learn all about Adrenalin (epinephrine): What it is and what does it do, characteristics, functions, effects, release, what happens when we have an excess, its medical uses, side effects, etc. We will solve all your doubts and answer all your questions. Continue reading this complete guide to adrenalin.

Adrenalin or Epinephrine
Adrenalin or Epinephrine

We’ve all heard of adrenalin. There are many activities or extreme sports that make us release large doses of adrenaline. We know that we generate this substance by experiencing strong emotions or experiencing extreme situations. An adrenaline rush speeds up our heart rate and breathing. When our body releases adrenaline we can feel our strength and energy increase, we feel euphoric, invincible. However, leaving aside when we release it, what do we really know about adrenaline? Here we answer all your questions:

What is Adrenalin?- Definition

Adrenalin also called epinephrine in its synthetic substitute, it is a molecule that we release in tense or stressful situations, or when we perceive that we are facing a threat. This substance allows triggering of different body processes that make us react to a potential danger. The effects of adrenaline or epinephrine have a specific purpose: to provide energy so that our muscles and our body can respond to a potential threat or a dangerous situation.

This substance triggers different body processes that make us react to a potential danger. The effects of adrenalin or epinephrine have a specific purpose: to provide energy so that our muscles and our body can respond to a potential threat or a dangerous situation.

Adrenalin or epinephrine predisposes us to act and react quickly, it prepares our organism so that we have the maximum response. That is why we say that this substance triggers our survival mechanisms, prepares us to face those situations where it is important that we react quickly.

Adrenalin or epinephrine has several body functions: When it is released into the bloodstream it acts as a hormone, and when adrenaline is released into the synaptic space (between two neurons) it acts as a neurotransmitter.

  • Adrenalin as a hormone: It travels through blood circulation helping it reach different cells and areas of our body, where it initiates multiple reactions.
  • Adrenalin as a neurotransmitter: Acts as a chemical messenger by sending signals from the nervous system. This substance is responsible for transmitting information from one neuron to the next. Its effect is closely related to attention, alertness and the brain reward system.

When we face a stressful, dangerous or risky situation, the adrenergic response is activated (a type of molecular receptor in the body’s cells, which receives signals of adrenalin, noradrenaline, and dopamine). Adrenaline is channeled through the blood and acts in different organs and parts of our body where it will cause specific effects in body activation: Opens the airways to increase the entrance of oxygen in the organism, constriction of the blood vessels, increased heart rate, etc.

This substance usually happens in stressful situations, excitement or nervousness. It is usually associated with extreme sports or activities that involve some risk, but we also release adrenalin in everyday situations. For example: when we face a test, or when we have an unexpected encounter with someone, an important meeting, or even your wedding day. Adrenaline or epinephrine also allows us, for example, to be able to study all night the day before an exam.


Origen of the word Adrenalin

This term comes from the Latin ad (which can be translated as “next to”) and renes (meaning “kidney”). So adrenalin can literally mean “next to the kidney”.  In the 1900s a Japanese chemist, Jokichi Takamine discovered, along with his assistant Keizo Uenaka, adrenalin. It was not until 1904 when adrenalin was synthesized in a laboratory independently (epinephrine), and this action was carried out by Friedrich Stolz and Henry Drysdale Dakin. The term epinephrine is often abbreviated to epi in medical jargon.

Are Adrenalin and Epinephrine the same?

Adrenalin is a substance that produces our own body naturally, specifically it is generated in the adrenal glands that are located just above our kidneys. However, this substance can also be synthesized in laboratories, is when it acquires the name of epinephrine (synthetic adrenalin) used in drugs or medicine. These two terms are used to refer to the hormone generated in the adrenal glands in stressful situations independently. This means that they are virtually synonymous terms.

Adrenalin Function: Activation Mechanisms

What is it for? Discover how this substance acts and its action mechanisms! The most important processes that trigger adrenalin upon being released in relatively high amounts are as follows.

1-Adrenalin’s effects on the lungs

Adrenaline or epinephrine is a bronchodilator. It allows the bronchi and muscles of the lungs to relax and dilate, and increase the rate at which we breathe in and out. Our respiratory capacity is multiplied, increasing the level of oxygen we process and receive our cells. Oxygenating more blood allows us to perform better physically.

2-Adrenalin’s effect on the heart and blood pressure

Adrenalin or epinephrine acts on our heart’s receptors, causing an increase in the force of contraction and increasing the heart rate and blood pressure. When our heart pumps more blood, our muscles receive more oxygen and can make more efforts: Run faster, jump higher, hit harder, etc.

3-Adrenalin’s effect on eyesight

Adrenaline or epinephrine dilates our pupils, allowing more light to enter. This can improve our ability to see and perceive. Helping us become more aware of everything that happens around us.

4-Adrenalin activates glycogen (energy reserve of muscles and liver)

Epinephrine activates the energy reserve present in the glycogen molecules. When the body or cells require an emergency energy supply, as in cases of tension, alert or imminent danger, glycogen is degraded to glucose, which is available for energy metabolism.

5- Adrenalin inhibits intestinal functioning

Our intestine spends a significant amount of energy in the process of nutrition and digestion. However, in moments of emergency in which we are facing a danger, this action is not decisive, so epinephrine or adrenalin is responsible for inhibiting this process so that it does not waste energy that we need to react efficiently to the danger.

6- Adrenalin activates metabolic changes in the body

When epinephrine is synthesized in with the receptors of our organism a series of metabolic changes originate. The binding of epinephrine to our adrenergic receptors can inhibit the release of insulin into the pancreas, stimulate glycogenolysis (glycogen degradation to glucose) in the liver and muscle. It promotes the secretion of glucagon in the pancreas to raise the glucose level in our blood, it also increases the secretion of adrenocorticotropic hormone (ACTH) in the pituitary and increases lipolysis in adipose tissue to meet energy needs.

All these effects promote the increase of the glycemia and concentration of fatty acids in our blood. This increases the production of energy inside our body cells.

Can we release adrenalin voluntarily? Ways to have an “adrenaline rush”

One way to produce adrenalin voluntarily without having to perform extreme sports or be in stressful situations is to force yourself to leave your comfort zone. Try new activities, go out with people with who you have never gone before, go to an unknown place, etc. These activities can help you generate a burst of additional energy.

Another way to get an adrenalin rush is by exposing yourself to frightening stimuli (watching scary movies, going to a haunted house, riding a roller coaster) or doing certain physical activities. However, you must be careful in searching this rush because you should never face anything that can cause you.

In the case of risky sports or roller coasters, a feeling of vertigo in the brain leads to a new alert situation, causing the release of adrenaline. When we step on the ground, we feel euphoric and excited.

Why do people need the adrenalin rush? Many people who experience anxiety symptoms or stress are looking for new ways to release more adrenaline. One of the explanations is that the release of this substance produces a (momentary) state of euphoria, maximizes energy and action capacity. Then the person feels a pleasant sensation of relaxation.

Adrenalin Rollercoaster
Adrenalin Rollercoaster

What happens when we release an excess of adrenalin?

This substance is necessary to act in times of danger or tension. Some people love the feeling of euphoria they feel after an adrenalin rush. It’s okay to search for it either by playing extreme sports, going to an amusement park or watching a scary movie.

However, people who are exposed to continuous or chronic stress, release this substance continuously which can harm and deteriorate your health.

Excessive adrenaline sometimes causes different pathologies, such as hypertension, headaches, migraines, nausea and even sleeping problems. For this reason, we have to be aware of the signals that our body sends us in the form of fatigue and sleep.

Another associated pathology is related to people who constantly experience very strong emotions (especially negatives). They are more likely to suffer cardiovascular accidents and obesity.

Along with cortisol, adrenalin causes more fat and sugars to be deposited in the abdomen. When a person becomes accustomed to the adrenaline discharges he ends up with similar symptoms to those of an addiction (asthenia, fear, nervousness, need to take stimulants).

In extreme cases, the immune system may begin to fail, leading to chronic diseases. Doctors have determined that sustained release of adrenaline may be contributing factors in the onset of diseases such as chronic fatigue or fibromyalgia.

In summary, high adrenalin symptoms are:

  • Increase in heart rate
  • Dilation of pupils
  • Increased respiration (oxygen gets to all organs faster)
  • Increased blood pressure
  • Control and retention of bowel transit.

Medical Uses of Adrenalin (Epinephrine)

Epinephrine (synthetic adrenaline) has saved many lives since it was developed. It has many medical uses, it allows to treat many emergency conditions that endanger our life such as cardiac arrest, anaphylactic shock (immunological reaction to food, insect bites, medications, etc.), bleeding, asthma attack, acute circulatory failure, bronchospasm, etc.

  • As for cardiac arrest: adrenalin is used to increase peripheral resistance through vasoconstriction.
  • Anaphylaxis (severe allergic reaction): adrenaline acts on this reaction due to its immunological properties.
  • It is included in some injectable local anesthetics (bupivacaine and lidocaine): The presence of adrenaline causes the absorption to be delayed due to its action as a vasoconstrictor and thus prolong the anesthetic action.

This type of medicine should only be used in emergencies, since it can have important side effects. It should not be used in case of allergies or in patients with heart failure, cerebral atherosclerosis, glaucoma or pheochromocytoma.

Side effects of Adrenalin

An injection of adrenalin may cause severe side effects such as: hypertension, tachycardia or palpitations (rapid or irregular heartbeat), peripheral vasoconstriction, cerebral hemorrhage, pulmonary edema, arrhythmia, angina pectoris, redness of the skin, inflammation, heat or sensitivity at the site of injection, difficulty breathing, nausea, vomiting, sweating, dizziness, anxiety, nervousness, restlessness, pale skin, weakness, headache, tremors, etc.

How does adrenalin work? Where is adrenalin produced

The organ in charge of releasing adrenaline from the adrenal glands is the hypothalamus (located in the brain). Faced with a dangerous situation, both strength and speed increase and the ability to feel pain decreases.

Adrenalin is synthesized in the adrenal gland that converts the amino acid tyrosine into a series of intermediates and eventually becomes adrenalin. It belongs to the group of catecholamines, which are a group of hormones related to stress response.

The process is as follows: tyrosine is oxidized first and levodopa is obtained. It is then decarboxylated to reach dopamine. This oxidation provides norepinephrine that is methylated and synthesized into epinephrine or adrenalin.

Why does it get released? The main causes are physical threats, intense emotions or high temperature. These stimuli are processed in the nervous system.

We hope you enjoyed this article and feel free to leave a comment or question below.

This article is originally in Spanish written by Sara Morales Alonso, translated by Alejandra Salazar.

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