What is leukotriens?

Leukotrienes are a group of biologically active compounds that play an important role in the body's immune response. They are produced by white blood cells called basophils and mast cells, and are involved in a variety of processes, including inflammation, allergy, and asthma. Leukotrienes are also involved in the regulation of blood flow, blood pressure, and airway constriction.

There are four main types of leukotrienes:

- Leukotriene B4 (LTB4): LTB4 is a potent inflammatory mediator that is involved in the recruitment of neutrophils, eosinophils, and other immune cells to sites of inflammation. It is also a chemoattractant for monocytes, macrophages, and dendritic cells.

- Leukotriene C4 (LTC4): LTC4 is a bronchoconstrictor that causes the narrowing of airways in the lungs. It is also a potent inflammatory mediator that is involved in the development of asthma, allergic rhinitis, and other allergic conditions.

- Leukotriene D4 (LTD4): LTD4 is a bronchoconstrictor that is also involved in the development of asthma, allergic rhinitis, and other allergic conditions. It is also a potent inflammatory mediator that is involved in the recruitment of eosinophils and other immune cells to sites of inflammation.

- Leukotriene E4 (LTE4): LTE4 is a weak bronchoconstrictor that is also involved in the development of asthma, allergic rhinitis, and other allergic conditions. It is also a potent inflammatory mediator that is involved in the recruitment of eosinophils and other immune cells to sites of inflammation.

Leukotrienes are produced in response to a variety of stimuli, including allergens, cytokines, and bacterial and viral infections. They can also be produced by non-immune cells, such as endothelial cells and epithelial cells.

The effects of leukotrienes are mediated by a variety of receptors, including the cysteinyl leukotriene receptors (CysLT1 and CysLT2) and the lipoxin A4 receptor (ALX). CysLT1 and CysLT2 receptors are expressed on a variety of immune cells, including eosinophils, basophils, mast cells, and dendritic cells. ALX receptors are expressed on monocytes, macrophages, and endothelial cells.

The activation of CysLT1 and CysLT2 receptors by leukotrienes leads to a variety of cellular responses, including:

- Bronchoconstriction

- Increased vascular permeability

- Eosinophil and neutrophil recruitment

- Release of inflammatory mediators

- Activation of mast cells and basophils

The activation of ALX receptors by leukotrienes leads to a variety of cellular responses, including:

- Inhibition of inflammation

- Reduction of vascular permeability

- Eosinophil and neutrophil apoptosis

- Release of anti-inflammatory mediators

Leukotrienes play an important role in the body's immune response, but their overproduction can lead to a variety of diseases, including asthma, allergic rhinitis, and other allergic conditions. Leukotriene inhibitors are a class of drugs that are used to treat these diseases by blocking the effects of leukotrienes.