Topic: Inflammation and repair, disturbances of growth and cancer
Question: Enumerate chemical mediators of acute inflammation. Give their mechanisms of action.
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Acute inflammation is a complex process that involves the release of various chemical mediators from damaged cells, immune cells, and blood vessels. These mediators help to initiate and propagate the inflammatory response. Here are some of the key chemical mediators of acute inflammation and their mechanisms of action:
- Histamine: Histamine is a vasoactive amine that is stored in mast cells and basophils. It is released in response to tissue injury or allergic reactions. Histamine causes vasodilation, increased vascular permeability, and recruitment of immune cells to the site of injury.
- Bradykinin: Bradykinin is a peptide that is generated from plasma proteins by the action of enzymes called kinins. It causes vasodilation, increased vascular permeability, and activation of pain receptors.
- Prostaglandins: Prostaglandins are lipid mediators that are synthesized from arachidonic acid by the action of cyclooxygenase enzymes. They cause vasodilation, increased vascular permeability, and activation of pain receptors.
- Leukotrienes: Leukotrienes are lipid mediators that are synthesized from arachidonic acid by the action of lipoxygenase enzymes. They cause vasodilation, increased vascular permeability, and recruitment of immune cells to the site of injury.
- Cytokines: Cytokines are a group of signaling proteins that are released by immune cells and other cells in response to tissue injury or infection. They include interleukins, tumor necrosis factor, and interferons. Cytokines help to coordinate the immune response and promote inflammation.
- Chemokines: Chemokines are a group of signaling proteins that are released by immune cells and other cells in response to tissue injury or infection. They help to recruit immune cells to the site of injury and promote inflammation.
- Complement proteins: Complement proteins are a group of plasma proteins that are activated in response to tissue injury or infection. They help to promote inflammation, recruit immune cells, and destroy pathogens.
The mechanisms of action of these chemical mediators involve binding to specific receptors on target cells, such as endothelial cells, immune cells, and smooth muscle cells. This binding triggers a cascade of intracellular signaling events that lead to changes in gene expression, cell activation, and the release of additional mediators. The overall effect is to promote inflammation, recruit immune cells, and facilitate tissue repair.
