Molecular basis Histamine is one of best-known Dilates blood vessels and increases permeability Mechanism of production Three peptides(c3a, C4a, and C5a; anaphylotoxins) produced by activation of complement system Stimulate release of histamine from mast cells BIOL 533 Lecture 5
BIOL 533 12 Lecture 5 Molecular Basis • Histamine is one of best-known – Dilates blood vessels and increases permeability – Mechanism of production • Three peptides (C3a, C4a, and C5a; anaphylotoxins) produced by activation of complement system • Stimulate release of histamine from mast cells
Molecular basis Kinin-small basic peptides Alter vascular tone Increase permeability May initiate or potentiate release of other chemical mediators from leukocytes Bradykinin is best-known BIOL 533 Lecture 5
BIOL 533 13 Lecture 5 Molecular Basis • Kinin—small basic peptides – Alter vascular tone – Increase permeability – May initiate or potentiate release of other chemical mediators from leukocytes • Bradykinin is best-known
Molecular basis Production of kinins Hageman factor activated during inflammation (one of substances that can activate is LPS Induces production of kinins Also plays important role in blood coagulation Cleavage of precursor kininogens activated by enzymes( kallikreins) produced during clotting cascade or release from granulocytes BIOL 533 Lecture 5
BIOL 533 14 Lecture 5 Molecular Basis • Production of kinins – Hageman factor activated during inflammation (one of substances that can activate is LPS) • Induces production of kinins • Also plays important role in blood coagulation – Cleavage of precursor kininogens activated by enzymes (kallikreins) produced during clotting cascade or release from granulocytes
Molecular basis Leukotrienes and prostaglandins Act on motility and metabolism of wbc Two plus certain phospholipids cause aggregation of blood platelets(important to stop bleeding) Prostaglandins synthesized in hypothalamus act on temperature regulatory centers of brain and cause fever BIOL 533 Lecture 5
BIOL 533 15 Lecture 5 Molecular Basis • Leukotrienes and prostaglandins – Act on motility and metabolism of wbc – Two plus certain phospholipids cause aggregation of blood platelets (important to stop bleeding) – Prostaglandins synthesized in hypothalamus act on temperature regulatory centers of brain and cause fever