Anaphylaxis: Mechanism and Role of Hormones

Anaphylaxis: Mechanism and Role of Hormones

Anaphylaxis is a severe and life-threatening allergic reaction that occurs when the body encounters an allergen it is sensitive to.

The mechanism of anaphylaxis is linked to hormones:

• Histamine: Histamine is a hormone released from mast cells in the body upon contact with an allergen. It plays a crucial role in triggering anaphylactic symptoms, such as:

• Vasodilation: Histamine dilates blood vessels, leading to a drop in blood pressure.

• Increased vascular permeability: Histamine increases the permeability of blood vessel walls, causing edema and swelling.

• Prostaglandins: This group of hormones has similar effects to histamine:

• Vasodilation

• Increased vascular permeability

The role of histamine in drug-induced anaphylaxis – hypersensitivity reaction:

• When a drug is injected, the body may have a hypersensitivity reaction to its components, leading to the release of histamine.

• Histamine causes vasodilation and increased vascular permeability, leading to symptoms such as:

• Decreased blood pressure

• Anaphylactic shock

• Edema

How do corticosteroid anti-inflammatory drugs work?

• Corticosteroids are potent anti-inflammatory drugs that act on the enzyme phospholipase.

• Phospholipase is an enzyme involved in the breakdown of phospholipids within cell membranes, producing precursors for prostaglandins and leukotrienes.

• By inhibiting phospholipase, corticosteroids suppress the synthesis of prostaglandins and leukotrienes, reducing inflammation and swelling.

Materials for eicosanoid synthesis:

• Eicosanoids are a group of hormones that include prostaglandins, leukotrienes, thromboxanes, and prostacyclins.

• The raw materials for eicosanoid synthesis are unsaturated fatty acids, which are broken down from cell membranes.

Leukotrienes:

• Leukotrienes are a type of eicosanoid that have a stronger effect than histamine in increasing vascular permeability.

• They contribute to the development of allergic and inflammatory reactions.

Origin from the eicosanoid family:

• In addition to prostaglandins and leukotrienes, the eicosanoid family also includes:

• Prostacyclin: Has vasodilating and anti-platelet aggregation effects.

• Thromboxane A2: Has vasoconstricting effects and promotes platelet aggregation.

Locally produced hormones:

• Locally produced hormones are those produced and act at the site of their production.

• Many locally produced hormones are polypeptides in nature.

• Examples include histamine, prostaglandins, and leukotrienes.

Hormones that stimulate fluid secretion:

• Secretin is a hormone secreted by the duodenum, which stimulates the pancreas to secrete pancreatic juice and the liver to secrete bile.

• Secretin plays a role in regulating digestion and secretion.

Antagonistic digestive hormones:

• Bombesin and VIP are two antagonistic digestive hormones.

• Bombesin stimulates gastric smooth muscle contraction and increases gastric acid secretion.

• VIP inhibits gastric smooth muscle contraction and reduces gastric acid secretion.

Note: This article provides basic information about the mechanism of anaphylaxis and the role of hormones. For a deeper understanding of this topic, it is recommended to consult specialized literature.