Flashcards in Eicosanoids Deck (13)
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1
Enzyme that catalyzes the formation of histamine
Histidine-decarboxylase catalyzes the formation of histamine from L-histidine
2
Where is histamine-decarboxylase located
• Mast cells, basophils, cells of the epidermis, cells in the gastric mucosa, neurons, cells of rapidly growing tissues (especially certain tumors)
3
H1 receptor acts via
Gq: increases IP3 and DAG
4
H2 receptor acts via
Gs: increases cAMP
5
H3 receptor acts via
Gi: decreases cAMP
6
H4 receptor acts via
Gi: decreases cAMP
7
H1 receptor is predominantly found in _______ where it ____
1. blood vessels
2.
➢ vasodilation: decreases BP (via NO release)
➢ Bronchoconstriction (features of anaphylaxis)
8
H2 receptor is predominantly found in _______ where it ____
stomach
2. stimulates gastric secretion
9
H3 receptor is predominantly found in _______
presynaptic: brain, myenteric plexus, other neurons
10
H4 receptor is predominantly found in _______
Eosinophils. neutrophils, CD4 T-cells
11
Histamine Release Inhibitors
• Beta2-adrenoceptor agonists
• Theophylline
• Cromolyn sodium and nedocromil
• Glucocorticoids (IgE-dependent release)
12
physiologic antagonists
Epinephrine (hence used in anaphylactic shock)
13
