Amine Autacoids - Histamine Flashcards
What is the biosynthesis of histamine
From amino acid histidine by decarboxylation
What is methylation
Large amount of histamine can cause what
Shock
Explain the distribution of histamine
The concentration of histamine is particularly high in where
What synthesizes and stores histamine
Mast cells and basophils
What are other cells that can release histamine
What is the main release of histamine due to
Allergic reaction (antigen-antibody)
Due to what is histamine released directly ?
What are the types of histamine receptors
H1
H2
H3
H4
Where is H1 present and what is its main function
Smooth muscle, endothelial cells, CNS - post synaptic only
Function - acute allergic reactions
Where is H2 present and what is its main function
Gastric parietal cells, cardiac muscle, mast cells, CNS - post-synaptic only
Function - gastric acid secretion
What are the H2 receptors in mast cells responsible for
Feedback Inhibition of histamine release from mast cells
Where is H3 present and what is its main function
CNS - pre and post synaptic
Neurotransmitter modulations
Where is H4 present and what is its main function
Cells of hematopoietic origin - eosinophils, mast cells, monocytes, basophils and T cells
Function - immunomodulator
What are the allergic symptoms due to histamine
Explain the regulation of gastric acid secretion as a physiological role of histamine
What is the result of blocking H2 receptor
Explain the physiological role of histamine in CNS
Explain H1 in CNS
Explain H2 receptors in CNS
Explain the physiological roles of histamine in CVS
