AUTACOIDS
AUTACOIDS GENERAL INFORMATION •Autos = self Akos = healing substance - inflammatory and immunological reactions - transmitters in nervous system. Types - • Amines –histamine, serotonin • Lipids –PG ,LT, PAF • Peptides –bradykinins, angiotensin • Others –TNFα ,Gastrin,somatostatin ,intestinal peptide HISTAMINE TISSUE AMINE •Mast cells –storage Ex --Skin lungs liver gastric mucosa placenta • Nonmast cell – 1) brain epidermis gastric mucosa and growing regions 2) blood ,most body secretions,venoms and pathological fluids . • Synthesis – amino acid histidine locally * Histamine liberation Venoms (insect/reptile bites) Food products (crabs, lobsters, fish) Trauma due to cold, chemical, thermal, radiant energy Antigen antibody reactions Drugs: d-tubocurarine,morphine, pethidine, amphetamine HISTAMINE RECEPTORS G Protein coupled -- H1 , H2 • H3 - only in brain • H4 • By convention antihistaminic drugs = H1 blockers .. • competitively block h