Histamine Flashcards
Histamine has what 2 compounds?
Amine
Imidazole
Mast cells
major histamine container,
Color change:BluetoRed
Two types of Mast Cell Categories
Connective tissue
Mucosal tissue
Mucosal tissue mast cells are stimulated by:
Interleukins
In the blood, where is most histamine found
Basophilic Leukocytes
What is slow turnover histamine release?
Mast cell histamine is slowly released
What is rapid release histamine?
Found in neurons,
vascular endothelium,
endocrine-like cells (stomach).
These are resistant to histamine releasing Rx.
What mediates or inhibits histamine release?
Macrophages,
Platelets.
Histamine made from what molecule & what is known to “induce” histamine?
L-histidine,
L-histidine decarboxylase,
histamine
What two pathways breakdown histamine?
Oxidation
Methylation
What is Skin Triple response
small red spot from dilation,
large flare from vasodilation of nerves,
wheal from edema.
What therapeutic uses for histamine?
NONE
Effects(receptor) of Histamine on Man?
Vasodilation H1, Gastric acid H2, Bronchospasm H1, Vomit/Diarrhea H1, /HR H2.
What use is H3?
Sleep,
Dementia,
Obesity.
What use is H4?
Anti-inflammatory
Non-immunological reaction & examples
Narcotics, contrast, NMB.
Does not require Ca or energy to produce histamine release and reaction.
Immunological reactions & examples
Histamine released by IgE cells binding to mast cells. They must see the antigen twice for the second time reaction.
Steps to “specific” immunologic release of histamine
be sensitized by first exposure,
second exposure activates IgEs,
release of Ca,
much more than just histamine is released by mast cells so the effects of activation is more than just from histamine
