If used properly, it can save lives; if used improperly, it can be fatal. What exactly is "adrenaline"?

When the human body is frightened, feels threatened, or performs strenuous exercise, it often produces some "amazing abilities", such as being injured in a fight without knowing it, bursting out with amazing physical strength in a fire, or soldiers on the battlefield running fast with their injured comrades on their backs.

At this time, the person's body will also produce some changes that are different from the past, such as increased heart rate, faster breathing, higher blood pressure, spurting blood, sweating, etc. In fact, the key factor that affects this series of body reactions is a hormone called "adrenaline".

When the human body is frightened, adrenaline rises

Source: Screenshots from TV series and movies

1

The discovery of adrenaline

In 1893, British physician George Oliver, in an experiment, found that subjects who took goat adrenal extract had a measurable constriction of their radial arteries. He asked physiology professor Edward Albert Sharpey-Schafer about this strange phenomenon.

Professor Chapeshar was also very excited after hearing Oliver's description. After unremitting efforts and research, the two finally found that the extract from animal adrenal glands has strong physiological activity. This substance has a strong excitatory effect on the blood vessels, heart and skeletal muscles of living animals.

Chapexar Source: Wikipedia

In 1894, Professor Chapeshar and Dr. Oliver jointly published an article explaining a substance extracted from the adrenal glands. Injecting this substance into animals can significantly increase blood pressure, speed up heartbeat, and constrict blood vessels.

Subsequently, the scientific community continued to study this mysterious substance. A year later, Polish physiologist Napoleon Cybulski extracted substances from the adrenal glands; American ophthalmologist William H. Bates discovered the use of adrenaline in ophthalmic surgery in 1896. In 1897, German scientist Sigmund Fränkel also extracted active substances from the adrenal glands based on the research of Schappeshar and Oliver, and named it "Spygmogenin".

Gao Fengrangji Source: Wikipedia

In 1901, Japanese scientist Takamine Jokichi first completed the world's first crystallization of adrenaline and officially named it adrenaline. Later in 1904, Friedrich Stoltz and Henry Lesdale Darkin independently synthesized the hormone in the laboratory.

2

Mechanism of action of adrenaline

After years of unremitting efforts and research by scientists, we now understand the true appearance and function of adrenaline. So how does it induce the body's stress response?

Epinephrine molecular formula

Source: Photo provided by the author

When the adrenal glands receive input from the nervous system, they release adrenaline into the bloodstream. For example, when the body is experiencing stress, adrenaline is released, which causes a state of alertness or energy and prepares the body for action, including increasing blood sugar levels and widening air passages.

The mechanism of action of adrenaline NA is sodium ion

Source: Internet

Adrenaline can induce increased contraction of vascular smooth muscle, contraction of pupil dilator muscle and contraction of intestinal sphincter. It can also trigger a series of metabolic changes in the body, stimulate glycolysis and inhibit insulin-mediated glycolysis in muscle.

At the same time, adrenaline can also trigger the secretion of glucagon, increase the secretion of adrenocorticotropic hormone in the pituitary gland, and increase lipolysis in adipose tissue. The direct effect caused by the above effects is the increase of blood sugar and fatty acids in the body, which provides substrates for energy production in cells throughout the body.

3

Adrenaline use

By understanding the mechanism of action of adrenaline in the body, we can use its principles to transform adrenaline to serve our health.

First, adrenaline can be used as a drug to treat a range of health conditions, especially anaphylactic shock and cardiac arrest. It can rapidly dilate the bronchi, producing a rapid, strong, short-term excitation effect; it can increase the heart rate and enhance myocardial contractility, thereby increasing myocardial oxygen consumption; it can dilate blood vessels and reduce peripheral vascular resistance, causing bronchial smooth muscle to relax and relieve bronchospasm.

Epinephrine for acute illness

Source: omicsonline.org

Then, adrenaline can be used as an immediate treatment method and can also be used to treat other acute diseases such as asthma, etc. It can inhibit the release of allergic substances from mast cells, shrink bronchial mucosal blood vessels, reduce capillary permeability, and thus eliminate bronchial mucosal edema.

Finally, adrenaline has a good hemostatic effect in pediatric strabismus correction and fracture internal fixation, can shorten the operation time, and is beneficial to the patient's postoperative recovery; in addition, adrenaline has a certain effect on lowering intraocular pressure and can be used to treat glaucoma.

Epinephrine for glaucoma

Source: iiiff.com

4

Side Effects of Epinephrine

Although the increased secretion of adrenaline is very helpful to our body in emergencies, improper use of medical adrenaline can cause palpitations, headaches, dizziness, vomiting, cold limbs, high blood pressure, etc. In severe cases, it can even lead to death from ventricular fibrillation. Edema, inflammation, and congestion can occur locally, and subcutaneous injection into blood vessels or excessive use can cause cerebral hemorrhage.

From the above, we can see that when we are frightened, the external manifestation of the body is caused by a series of complex biochemical reactions caused by the increase of adrenaline in the body. On the other hand, the rational use of adrenaline in medicine is of great help in saving lives and restoring health.

Audit expert: Wu Xinsheng

Deputy Chief Physician, Department of Gastroenterology, PLA 371 Hospital

Source: Digital Beijing Science Center