Mediators Flashcards
Plasma derived mediators
Kinins
Complements
Coagulation system
Plasminolysis system
Locally produced mediators
Histamine Serotonin / 5HT Platelet activating factor (PAF) Prostaglandins Leukotrienes Nitric oxide
it is generated from the membrane phospholipids of neutrophils, monocytes, basophils, endothelium, and platelets (and other cells)by the action of phospholipase A2.
Platelet activating factor (PAF)
: are polypeptide products of many cell types (but principally activated lymphocytes and macrophages) that modulate the function of other cell types
Cytokines
platelet stimulation, vasoconstriction and vasodilation, increased vascular permeability and bronchoconstriction, enhances leukocyte adhesion, chemotaxis, leukocyte degranulation, and the oxidative burst
PAF
augmented by a number of stimuli including: bacterial endotoxin, immune complex formation, C3a, bradykinin & IL-1
cyclooxygenase pathway
**major sources in the acute inflammatory response include monocytes, macrophages, endothelial cells and platelets
Products of this pathway include prostaglandin (PGE2), PGD2, PGF2a, PGI2 (prostacyclin), and thromboxane A2 (TXA2)
cyclooxygenase pathway
may be released from endothelial cells upon stimulation by acetylcholine and bradykinin where it acts as a potent vasodilator and inhibitor of platelet aggregation
NO
synthesized and stored in mast cells, platelets and basophils
Histamine
promote pain, fever, vasodilation and increased vascular permeability
cyclooxygenase pathway
Products of this pathway include prostaglandin (PGE2), PGD2, PGF2a, PGI2 (prostacyclin), and thromboxane A2 (TXA2)
synthesized and released from neutrophils, basophils and mast cells
lipoxygenase pathway
diffuses rapidly through the blood stream
-promotes vasodilation, and increased vascular permeability
Histamine
LTA4 can be taken up by…….and converted to LTB4 and LTC4
Platelets,RBCs and endothelial cells
group of serine proteases
Kinins
Vasoconstriction
PAF,LT
neutrophil activation and chemotaxis and adhesion
LTB4
recognized by specific receptors (H1, H2 and H3)
Histamine
The functions of the complement system are mediated by
by breakdown products of C3 and other complement proteins, & by the membrane attack complex (MAC).
may also be released from macrophages upon stimulation with IFN-g and TNF-a
NO
stored in platelets, mast cells and enterochromaffin cells of the GI tract
-has vasoactive properties
Serotonin
Protein cell products that act as a message to other cells, telling them how to behave & modulate their function
Products of many cell types (principally activated lymphocytes & macrophages)
Produced during immune and inflammatory responses
Cytokines
IL-1, TNF-a and -B, IFN-y are especially important in inflammation.
Induce the systemic acute-phase responses, these include fever, lethargy, hepatic synthesis of various proteins, metabolic wasting (cachexia), neutrophil release into the circulation, and release of adrenocorticotropic hormone (inducing corticosteroid synthesis and release)
Cytokines
Thrombin
Enhancing leukocyte adhesion, vascular permeability and chemotactic
activates the complement pathway
Plasmin
