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The C3a, C4a and C5a components are referred to as anaphylatoxins: [4] [5] they cause smooth muscle contraction, vasodilation, histamine release from mast cells, and enhanced vascular permeability. [5] They also mediate chemotaxis, inflammation, and generation of cytotoxic oxygen radicals. [5]
Platelets release other proinflammatory factors like serotonin, bradykinin, prostaglandins, prostacyclins, thromboxane, and histamine, [3] which serve several purposes, including increasing cell proliferation and migration to the area and causing blood vessels to become dilated and porous.
Another important site of histamine storage and release is the enterochromaffin-like (ECL) cell of the stomach. The most important pathophysiologic mechanism of mast cell and basophil histamine release is immunologic. These cells, if sensitized by IgE antibodies attached to their membranes, degranulate when exposed to the appropriate antigen.
With multiple sclerosis, inflammation settles in the central nervous system after immune cells attack the coating on nerves; lupus can cause inflammation in the heart, brain, kidney, and other organs.
The triple response of Lewis is due to the release of histamine. Histamine, or 2-(imidazol-4-yl)ethanamine, is a dibasic vasoactive amine that is located in most body tissues but is highly concentrated in the lungs, skin, and gastrointestinal tract. Histamine is a small molecule, stored in granules of mast cells and basophils. Mast cells and ...
The Fc region of immunoglobulin E (IgE) becomes bound to mast cells and basophils, and when IgE's paratopes bind to an antigen, it causes the cells to release histamine and other inflammatory mediators. [6] These similarities have led many to speculate that mast cells are basophils that have "homed in" on tissues.
Histamine is a weak base (a compound able to react with a hydrogen ion to form an acid) that can link with acid groups within the granules of the mast cells. [8] The mechanism of the displacement theory. The crux of this theory lies in the assumption that histamine liberators release histamine by displacing it from cells.
Histamine can cause bladder inflammation and contribute to the symptoms of such bladder diseases as cystitis (inflammation of the bladder) or painful bladder disease. Histamine binds to H 2 receptors in the bladder smooth muscle, leading to relaxation [contradictory] of the bladder muscle and promotion of urine storage. Histamine does not seem ...