Understanding the Role of Adrenaline in the Fight or Flight Response

Adrenaline or epinephrine hormones

Adrenaline, also known as epinephrine, is a hormone and neurotransmitter produced by the adrenal glands. It plays an important role in the body's fight or flight response to stress or danger.

When a person perceives a threat, whether real or imagined, the body responds by releasing adrenaline into the bloodstream. This triggers a number of physiological changes, including increased heart rate, blood pressure, and respiration. These changes prepare the body for action, allowing it to respond quickly and effectively to the perceived threat.

Adrenaline also has other effects on the body, including the dilation of the pupils, increased blood flow to the muscles, and the release of glucose from the liver, providing the body with the energy it needs to respond to the perceived danger.

While adrenaline can be helpful in emergency situations, it can also have negative effects on the body over time if it is released too frequently or in response to non-threatening situations. Chronic stress and anxiety can lead to an overactive fight or flight response, resulting in increased levels of adrenaline in the body that can contribute to a range of health problems, including cardiovascular disease and high blood pressure.

Adrenaline belongs to the sympathomimetics class of drugs. primarily given for the treatment of cardiac arrest, hypotension due to shock, and life-threatening allergic reactions. 

Adrenaline should be taken as advised by a doctor. It is available in the form of injection. Adrenaline is also known as epinephrine. It is a life-saving drug.  Adrenaline is widely used in abnormal heart function, blood pressure, and eye preparations. It is used for, cardiac arrest. hypotension due to shock, and life-threatening allergic reactions.

Effects to the body of adrenaline or epinephrine 

Adrenaline or epinephrine has several effects on the body, which can be both helpful and harmful, depending on the situation. While adrenaline can be helpful in emergency situations, chronic stress or anxiety can lead to an overactive fight or flight response, resulting in excessive release of adrenaline, which can contribute to health problems such as high blood pressure, cardiovascular disease, and anxiety disorders.
some of the effects of adrenaline:
Increased heart rate: Adrenaline stimulates the heart, causing it to beat faster and harder. This increases blood flow to the muscles and organs, preparing the body for action.
Elevated blood pressure: Adrenaline causes the blood vessels to constrict, increasing blood pressure.
Dilated pupils: Adrenaline causes the pupils to dilate, allowing more light into the eyes and improving vision.
Increased respiration: Adrenaline stimulates the respiratory system, causing the person to breathe faster and more deeply.
Increased glucose production: Adrenaline stimulates the liver to produce glucose, providing the body with the energy it needs to respond to a perceived threat.
Suppressed digestion: Adrenaline suppresses digestion, diverting blood flow away from the digestive system and towards the muscles and organs.
Increased sweating: Adrenaline stimulates the sweat glands, causing the person to sweat more, which can help cool the body down during physical activity.
Increased blood clotting: Adrenaline stimulates blood clotting, which can be helpful in the event of an injury, but can also increase the risk of blood clots and stroke over time.

On the heart

Adrenaline increases heart rate, the force of contraction, and cardiac output. Adrenaline increases blood pressure, due to its direct effect on the heart and vasoconstriction of blood vessels. 

Due to its direct effect on the heart and vasoconstriction of blood vessels, adrenaline relaxes the bronchial smooth muscles and produces bronchodilation. Adrenaline reduces GIT motility

On Eyes

Adrenaline produces dilation of pupils i. e, mydriasis

Side effects of adrenaline

• Severe hypertension
• Palpitation
• Cardiac arrhythmia
• Acute pulmonary edema
• Fear, 
• Anxiety 
• Restlessness
• Headaches, 
• Tremors.

Uses of adrenaline 

• Adnerline uses in bronchial asthma
• Allergy reaction
•  Cardiac arrest
• Control the hemorrhage
• Added with local anesthetic drugs.

Should not treat by adrenalin Contraindications

• Hypertension
• Thyrotoxicosis
• Arteriosclerosis
• Spinal anesthesia.

What is dale vasomotor reversal?

Adrenaline îs a mixed agonist that produces an increase in systolic but decreases in diastolic blood pressure.

A secondary fall occurs when the concentration of adrenaline decreases.

The drugs like ergotoxine reverse the actions of adrenaline which is called " Dale's vasomotor reversal"

the vasoconstrictor action of adrenaline is blocked by ergot alkaloid. this may lead to stimulation of both

receptors by adrenaline and thus causing a fall in blood pressure.

The high dose of adrenaline with ergot extract also blocks the effects of adrenaline.