What are the function of vasosctive smines.

Histamine and Serotonin are two major vasoactive amines. They are so called because they have important actions on blood vessels.
They are stored as preformed molecule in mast cell, basophils, platelets and on activation these cell release vasoactive amines.

Functions of vasoactive amines:
 Histamine:

• Principal mediators of the immediate transient phase of increased vascular permeability. (Increased vascular permeability)
• Histamine causes dilation of arterioles and increases the permeability of venules. (Vasodilation) 
• Endothelial activation.
• Contraction of some smooth muscles.

Serotonin: 

•  Neurotransmitter in the gastrointestinal tract.
• Vasoconstrictor.