Leukotrienit

Leukotrienes are a group of biologically active lipids that are released from cell membranes by the action of enzymes. They are synthesized from arachidonic acid, a fatty acid found in cell membranes. Leukotrienes play a significant role in inflammatory and allergic responses.

The primary cells involved in the synthesis and release of leukotrienes are mast cells, eosinophils, basophils, and macrophages. Upon stimulation, these cells activate enzymes like 5-lipoxygenase, which initiates the cascade leading to leukotriene production. There are several types of leukotrienes, with the cysteinyl leukotrienes (LTC4, LTD4, and LTE4) being the most well-studied and pharmacologically important.

Cysteinyl leukotrienes exert their effects by binding to specific G protein-coupled receptors on target cells, including smooth muscle cells, endothelial cells, and inflammatory cells. This binding leads to a variety of physiological responses. In the airways, they cause bronchoconstriction, increased mucus production, and airway edema, contributing to the symptoms of asthma. In the context of allergic reactions, they promote vascular permeability and the recruitment of inflammatory cells to the site of inflammation.

Leukotrienes are also implicated in other inflammatory conditions such as inflammatory bowel disease and psoriasis. The understanding of leukotriene pathways has led to the development of leukotriene receptor antagonists and 5-lipoxygenase inhibitors as therapeutic agents for conditions like asthma and allergic rhinitis. These medications work by blocking the action or synthesis of leukotrienes, thereby reducing inflammation and its associated symptoms.